diff --git a/Makefile b/Makefile
index 87f5e00..c43c028 100644
--- a/Makefile
+++ b/Makefile
@@ -8,7 +8,7 @@ endif
 
 CC      = gcc
 TARGET  = jzboot
-SOURCES = debug.c devmgr.c ingenic.c main.c shell_lex.c usbdev.c shell.c config.c spl_cmdset.c usbboot_cmdset.c
+SOURCES = debug.c devmgr.c ingenic.c main.c shell_lex.c usbdev.c shell.c shell_builtins.c config.c spl_cmdset.c usbboot_cmdset.c
 CFLAGS  = --std=gnu99 -Wall -Werror -O2 $(shell pkg-config libusb-1.0 --cflags)
 LIBS    += $(shell pkg-config libusb-1.0 --libs)
 
diff --git a/main.c b/main.c
index 663ab08..e94aa93 100644
--- a/main.c
+++ b/main.c
@@ -146,7 +146,9 @@ int main(int argc, char *argv[]) {
 		goto exit_usb;
 	}
 
-	if(shell_init(ingenic) == -1) {
+	shell_context_t *shell = shell_init(ingenic);
+
+	if(shell == NULL) {
 		perror("shell_init");
 
 		ret = 1;
@@ -155,7 +157,7 @@ int main(int argc, char *argv[]) {
 	}
 
 	if(config)
-		if(shell_source(config) == -1) {
+		if(shell_source(shell, config) == -1) {
 			perror("shell_source");
 
 			ret = 1;
@@ -164,23 +166,23 @@ int main(int argc, char *argv[]) {
 		}
 
 	if(cmd != NULL) {
-		if(shell_execute(cmd) == -1) {
+		if(shell_execute(shell, cmd) == -1) {
 			perror("shell_execute");
 
 			ret = 1;
 		}
 
 	} else if(script != NULL) {
-		if(shell_source(script) == -1) {
+		if(shell_source(shell, script) == -1) {
 			perror("shell_source");
 
 			ret = 1;
 		}
 	} else
-		shell_interactive();
+		shell_interactive(shell);
 
 exit_shell:
-	shell_fini();
+	shell_fini(shell);
 
 exit_ingenic:
 	ingenic_close(ingenic);
diff --git a/shell.c b/shell.c
index 913e6e3..32e1d64 100644
--- a/shell.c
+++ b/shell.c
@@ -27,42 +27,9 @@
 #include <unistd.h>
 #include <errno.h>
 
-#include "shell.h"
+#include "shell_internal.h"
 #include "debug.h"
 #include "ingenic.h"
-#include "config.h"
-
-static void *device = NULL;
-static char linebuf[512];
-char *strval = NULL, *line = NULL;
-
-int yylex();
-void yyrestart(FILE *new_file);
-
-static int builtin_help(int argc, char *argv[]);
-static int builtin_exit(int argc, char *argv[]);
-static int builtin_source(int argc, char *argv[]);
-static int builtin_echo(int argc, char *argv[]);
-static int builtin_sleep(int argc, char *argv[]);
-static int builtin_redetect(int argc, char *argv[]);
-static int builtin_rebuildcfg(int argc, char *argv[]);
-static int builtin_set(int argc, char *argv[]);
-static int builtin_safe(int argc, char *argv[]);
-
-static const shell_command_t commands[] = {
-	{ "help", "- Display this message", builtin_help },
-	{ "exit", "- Batch: stop current script, interactive: end session", builtin_exit },
-	{ "source", "<FILENAME> - run specified script", builtin_source },
-	{ "echo", "<STRING> - output specified string", builtin_echo },
-	{ "sleep", "<MILLISECONDS> - sleep a specified amount of time", builtin_sleep },
-	{ "set", "[VARIABLE] [VALUE] - print or set configuraton variables", builtin_set },
-	{ "safe", "<COMMAND> [ARG]... - run command ignoring errors", builtin_safe },
-
-	{ "redetect", " - Redetect CPU", builtin_redetect },
-	{ "rebuildcfg", " - Rebuild firmware configuration data", builtin_rebuildcfg },
-
-	{ NULL, NULL, NULL }
-};
 
 static void shell_update_cmdset(void *arg);
 
@@ -70,64 +37,106 @@ static const ingenic_callbacks_t shell_callbacks = {
 	shell_update_cmdset,
 };
 
-static const shell_command_t *set_cmds = NULL;
-static int shell_exit = 0;
+static const struct {
+	int set;
+	const char *name;
+	const shell_command_t *commands;
+} cmdsets[] = {
+	{ CMDSET_SPL,     "SPL",     spl_cmdset },
+	{ CMDSET_USBBOOT, "USBBoot", usbboot_cmdset },
+	{ 0,          NULL,  NULL }
+};
 
-int shell_init(void *ingenic) {
+shell_context_t *shell_init(void *ingenic) {
 #ifdef WITH_READLINE
 	rl_initialize();
 #endif
 
 	debug(LEVEL_DEBUG, "Initializing shell\n");
 
-	device = ingenic;
+	shell_context_t *ctx = malloc(sizeof(shell_context_t));
+	memset(ctx, 0, sizeof(shell_context_t));
+	ctx->device = ingenic;
 
-	ingenic_set_callbacks(ingenic, &shell_callbacks, NULL);
+	ingenic_set_callbacks(ingenic, &shell_callbacks, ctx);
 
-	shell_update_cmdset(NULL);
+	shell_update_cmdset(ctx);
+
+	return ctx;
+}
+
+int shell_enumerate_commands(shell_context_t *ctx, int (*callback)(shell_context_t *ctx, const shell_command_t *cmd, void *arg), void *arg) {
+	for(int i = 0; builtin_cmdset[i].cmd != NULL; i++) {
+		int ret = callback(ctx, builtin_cmdset + i, arg);
+
+		if(ret != 0)
+			return ret;
+	}
+
+	if(ctx->set_cmds)
+		for(int i = 0; ctx->set_cmds[i].cmd != NULL; i++) {
+			int ret = callback(ctx, ctx->set_cmds + i, arg);
+
+			if(ret != 0)
+				return ret;
+		}
 
 	return 0;
 }
 
-#define STATE_WANTSTR	0
-#define STATE_WANTSPACE	1
+static int shell_run_function(shell_context_t *ctx, const shell_command_t *cmd, void *arg) {
+	shell_run_data_t *data = arg;
 
-int shell_run(int argc, char *argv[]) {
-	for(int i = 0; commands[i].cmd != NULL; i++)
-		if(strcmp(commands[i].cmd, argv[0]) == 0)
-			return commands[i].handler(argc, argv);
+	if(strcmp(cmd->cmd, data->argv[0]) == 0) {
+		int ret = cmd->handler(ctx, data->argc, data->argv);
 
-	if(set_cmds) {
-		for(int i = 0; set_cmds[i].cmd != NULL; i++)
-			if(strcmp(set_cmds[i].cmd, argv[0]) == 0)
-				return set_cmds[i].handler(argc, argv);
-	}
-
-	debug(LEVEL_ERROR, "Bad command '%s'\n", argv[0]);
-
-	errno = EINVAL;
-	return -1;
+		if(ret == 0)
+			return 1;
+		else
+			return ret;
+	} else
+		return 0;
 }
 
-int shell_execute(const char *cmd) {
-	line = strdup(cmd);
-	char *ptr = line;
+int shell_run(shell_context_t *ctx, int argc, char *argv[]) {
+	shell_run_data_t data = { argc, argv };
+
+	int ret = shell_enumerate_commands(ctx, shell_run_function, &data);
+
+	if(ret != 0) {
+		debug(LEVEL_ERROR, "Bad command '%s'\n", argv[0]);
+
+		errno = EINVAL;
+		return -1;
+
+	} else if(ret == 1) {
+		return 0;
+	} else
+		return ret;
+}
+
+int shell_execute(shell_context_t *ctx, const char *cmd) {
+	yyscan_t scanner;
+	if(yylex_init_extra(ctx, &scanner) == -1)
+		return -1;
+
+	ctx->line = strdup(cmd);
+	char *ptr = ctx->line;
 
 	int token;
 	int state = STATE_WANTSTR;
 	int argc = 0;
 	char **argv = NULL;
-
-	yyrestart(NULL);
+	int fret = -1;
 
 	do {
 		int noway = 0;
 
-		token = yylex();
+		token = yylex(&scanner);
 
 		if((token == TOK_SEPARATOR || token == TOK_COMMENT || token == 0)) {
 			if(argc > 0) {
-				int ret = shell_run(argc, argv);
+				int ret = shell_run(ctx, argc, argv);
 
 				for(int i = 0; i < argc; i++) {
 					free(argv[i]);
@@ -139,9 +148,9 @@ int shell_execute(const char *cmd) {
 				argc = 0;
 
 				if(ret == -1) {
-					free(ptr);
+					fret = -1;
 
-					return -1;
+					break;
 				}
 			}
 
@@ -156,7 +165,7 @@ int shell_execute(const char *cmd) {
 
 					argv = realloc(argv, sizeof(char *) * argc);
 
-					argv[oargc] = strval;
+					argv[oargc] = ctx->strval;
 
 					state = STATE_WANTSPACE;
 				} else {
@@ -167,7 +176,7 @@ int shell_execute(const char *cmd) {
 
 			case STATE_WANTSPACE:
 				if(token == TOK_STRING) {
-					free(strval);
+					free(ctx->strval);
 
 					noway = 1;
 				} else if(token == TOK_SPACE) {
@@ -183,9 +192,10 @@ int shell_execute(const char *cmd) {
 					free(argv[i]);
 
 				free(argv);
-				free(ptr);
 
-				return -1;
+				fret = -1;
+
+				break;
 			}
 		}
 
@@ -193,28 +203,30 @@ int shell_execute(const char *cmd) {
 
 	free(ptr);
 
-	return 0;
+	yylex_destroy(&scanner);
+
+	return fret;
 }
 
-int shell_pull(char *buf, int maxlen) {
-	size_t len = strlen(line);
+int shell_pull(shell_context_t *ctx, char *buf, int maxlen) {
+	size_t len = strlen(ctx->line);
 
 	if(len < maxlen)
 		maxlen = len;
 
-	memcpy(buf, line, maxlen);
+	memcpy(buf, ctx->line, maxlen);
 
-	line += maxlen;
+	ctx->line += maxlen;
 
 	return maxlen;
 }
 
-void shell_fini() {
-	device = NULL;
+void shell_fini(shell_context_t *ctx) {
+	free(ctx);
 }
 
-int shell_source(const char *filename) {
-	shell_exit = 0;
+int shell_source(shell_context_t *ctx, const char *filename) {
+	ctx->shell_exit = 0;
 
 	FILE *file = fopen(filename, "r");
 
@@ -224,8 +236,8 @@ int shell_source(const char *filename) {
 
 	char *line;
 
-	while((line = fgets(linebuf, sizeof(linebuf), file)) && !shell_exit) {
-		if(shell_execute(line) == -1) {
+	while((line = fgets(ctx->linebuf, sizeof(ctx->linebuf), file)) && !ctx->shell_exit) {
+		if(shell_execute(ctx, line) == -1) {
 			fclose(file);
 
 			return -1;
@@ -237,38 +249,37 @@ int shell_source(const char *filename) {
 	return 0;
 }
 
-void shell_interactive() {
-	shell_exit = 0;
+void shell_interactive(shell_context_t *ctx) {
+	ctx->shell_exit = 0;
 
 #ifndef WITH_READLINE
 	char *line;
 
-	while(!shell_exit) {
+	while(!ctx->shell_exit) {
 		fputs("jzboot> ", stdout);
 		fflush(stdout);
 
-		line = fgets(linebuf, sizeof(linebuf), stdin);
+		line = fgets(ctx->linebuf, sizeof(ctx->linebuf), stdin);
 
 		if(line == NULL)
 			break;
 
-		shell_execute(line);
+		shell_execute(ctx, line);
 	}
 #else
 
 	rl_set_signals();
 
-	while(!shell_exit) {
+	while(!ctx->shell_exit) {
 		char *line = readline("jzboot> ");
 
 		if(line == NULL) {
-			printf("line null, EOP\n");
 			break;
 		}
 
 		add_history(line);
 
-		shell_execute(line);
+		shell_execute(ctx, line);
 
 		free(line);
 	}
@@ -277,153 +288,18 @@ void shell_interactive() {
 #endif
 }
 
-static int builtin_help(int argc, char *argv[]) {
-	for(int i = 0; commands[i].cmd != NULL; i++) {
-		printf("%s %s\n", commands[i].cmd, commands[i].description);
-	}
-
-	if(set_cmds) {
-		for(int i = 0; set_cmds[i].cmd != NULL; i++)
-			printf("%s %s\n", set_cmds[i].cmd, set_cmds[i].description);
-	}
-
-	return 0;
-}
-
-static int builtin_exit(int argc, char *argv[]) {
-	shell_exit = 1;
-
-	return 0;
-}
-
-static int builtin_source(int argc, char *argv[]) {
-	if(argc != 2) {
-		printf("Usage: %s <FILENAME>\n", argv[0]);
-
-		return -1;
-	}
-
-	int ret = shell_source(argv[1]);
-
-	if(ret == -1) {
-		fprintf(stderr, "Error while sourcing file %s: %s\n", argv[1], strerror(errno));
-	}
-
-	shell_exit = 0;
-
-	return ret;
-}
-
-static int builtin_echo(int argc, char *argv[]) {
-	if(argc < 2) {
-		printf("Usage: %s <STRING>\n", argv[0]);
-
-		return -1;
-	}
-
-	for(int i = 1; i < argc; i++) {
-		fputs(argv[i], stdout);
-
-		putchar((i < argc - 1) ? ' ' : '\n');
-	}
-
-	return 0;
-}
-
-static int builtin_sleep(int argc, char *argv[]) {
-	if(argc != 2) {
-		printf("Usage: %s <MILLISECONDS>\n", argv[0]);
-
-		return -1;
-	}
-
-	uint32_t ms = atoi(argv[1]);
-
-	usleep(ms * 1000);
-
-	return 0;
-}
-
-static int builtin_redetect(int argc, char *argv[]) {
-	if(argc != 1) {
-		printf("Usage: %s\n", argv[0]);
-
-		return -1;
-	}
-
-	if(ingenic_redetect(device) == -1) {
-		perror("ingenic_redetect");
-
-		return -1;
-	} else
-		return 0;
-}
-
-
-static int builtin_set(int argc, char *argv[]) {
-	if(argc == 1 && cfg_environ) {
-		for(int i = 0; cfg_environ[i] != NULL; i++)
-			printf("%s\n", cfg_environ[i]);
-
-	} else if(argc == 2) {
-		cfg_unsetenv(argv[1]);
-
-	} else if(argc == 3) {
-		cfg_setenv(argv[1], argv[2]);
-
-	} else {
-		printf("Usage: %s [VARIABLE] [VALUE]\n", argv[0]);
-
-		return -1;
-	}
-
-	return 0;
-}
-
-
-static int builtin_rebuildcfg(int argc, char *argv[]) {
-	if(argc != 1) {
-		printf("Usage: %s\n", argv[0]);
-
-		return -1;
-	}
-
-	return ingenic_rebuild(device);
-}
-
-static int builtin_safe(int argc, char *argv[]) {
-	if(argc < 2) {
-		printf("Usage: %s <COMMAND> [ARG]...\n", argv[0]);
-
-		return -1;
-	}
-
-	if(shell_run(argc - 1, argv + 1) == -1)
-		perror("shell_run");
-
-	return 0;
-}
-
-static const struct {
-	int set;
-	const char *name;
-	const shell_command_t *commands;
-} cmdsets[] = {
-	{ CMDSET_SPL,     "SPL",     spl_cmdset },
-	{ CMDSET_USBBOOT, "USBBoot", usbboot_cmdset },
-	{ 0,          NULL,  NULL }
-};
-
 static void shell_update_cmdset(void *arg) {
-	set_cmds = NULL;
+	shell_context_t *ctx = arg;
 
-	int set = ingenic_cmdset(device);
+	ctx->set_cmds = NULL;
+
+	int set = ingenic_cmdset(ctx->device);
 
 	for(int i = 0; cmdsets[i].name != NULL; i++) {
 		if(cmdsets[i].set == set) {
-			printf("Shell: using command set '%s', run 'help' for command list. CPU: %04X\n", cmdsets[i].name, ingenic_type(device));
+			printf("Shell: using command set '%s', run 'help' for command list. CPU: %04X\n", cmdsets[i].name, ingenic_type(ctx->device));
 
-			set_cmds = cmdsets[i].commands;
+			ctx->set_cmds = cmdsets[i].commands;
 
 			return;
 		}
@@ -432,6 +308,11 @@ static void shell_update_cmdset(void *arg) {
 	debug(LEVEL_ERROR, "Shell: unknown cmdset %d\n", set);
 }
 
-void *shell_device() {
-	return device;
+void *shell_device(shell_context_t *ctx) {
+	return ctx->device;
 }
+
+void shell_exit(shell_context_t *ctx, int val) {
+	ctx->shell_exit = val;
+}
+
diff --git a/shell.h b/shell.h
index 0f11518..8a77369 100644
--- a/shell.h
+++ b/shell.h
@@ -19,32 +19,30 @@
 #ifndef __SHELL__H__
 #define __SHELL__H__
 
-typedef struct {
+#ifndef SHELL_INTERNALS
+typedef void shell_context_t;
+#endif
+
+typedef struct shell_command {
 	const char *cmd;
 	const char *description;
-	int (*handler)(int argc, char *argv[]);
+	int (*handler)(shell_context_t *ctx, int argc, char *argv[]);
 } shell_command_t;
 
-int shell_init(void *ingenic);
-void shell_fini();
+shell_context_t *shell_init(void *ingenic);
+void shell_fini(shell_context_t *context);
 
-void shell_interactive();
-int shell_source(const char *filename);
-int shell_execute(const char *input);
+void shell_interactive(shell_context_t *ctx);
+int shell_source(shell_context_t *ctx, const char *filename);
+int shell_execute(shell_context_t *ctx, const char *input);
+void *shell_device(shell_context_t *ctx);
+int shell_run(shell_context_t *ctx, int argc, char *argv[]);
 
-void *shell_device();
-
-// lexer interface
-extern char *strval;
-
-#define TOK_SEPARATOR	1
-#define TOK_STRING	2
-#define TOK_SPACE	3
-#define TOK_COMMENT	4
-
-int shell_pull(char *buf, int maxlen);
+void shell_exit(shell_context_t *ctx, int val);
+int shell_enumerate_commands(shell_context_t *ctx, int (*callback)(shell_context_t *ctx, const shell_command_t *cmd, void *arg), void *arg);
 
 extern const shell_command_t spl_cmdset[];
 extern const shell_command_t usbboot_cmdset[];
+extern const shell_command_t builtin_cmdset[];
 
 #endif
diff --git a/shell_builtins.c b/shell_builtins.c
new file mode 100644
index 0000000..675da32
--- /dev/null
+++ b/shell_builtins.c
@@ -0,0 +1,181 @@
+/*
+ * JzBoot: an USB bootloader for JZ series of Ingenic(R) microprocessors.
+ * Copyright (C) 2010  Sergey Gridassov <grindars@gmail.com>,
+ *                     Peter Zotov <whitequark@whitequark.org>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <errno.h>
+
+#include "shell.h"
+#include "config.h"
+#include "ingenic.h"
+
+static int builtin_help(shell_context_t *ctx, int argc, char *argv[]);
+static int builtin_exit(shell_context_t *ctx, int argc, char *argv[]);
+static int builtin_source(shell_context_t *ctx, int argc, char *argv[]);
+static int builtin_echo(shell_context_t *ctx, int argc, char *argv[]);
+static int builtin_sleep(shell_context_t *ctx, int argc, char *argv[]);
+static int builtin_redetect(shell_context_t *ctx, int argc, char *argv[]);
+static int builtin_rebuildcfg(shell_context_t *ctx, int argc, char *argv[]);
+static int builtin_set(shell_context_t *ctx, int argc, char *argv[]);
+static int builtin_safe(shell_context_t *ctx, int argc, char *argv[]);
+
+const shell_command_t builtin_cmdset[] = {
+	{ "help", "- Display this message", builtin_help },
+	{ "exit", "- Batch: stop current script, interactive: end session", builtin_exit },
+	{ "source", "<FILENAME> - run specified script", builtin_source },
+	{ "echo", "<STRING> - output specified string", builtin_echo },
+	{ "sleep", "<MILLISECONDS> - sleep a specified amount of time", builtin_sleep },
+	{ "set", "[VARIABLE] [VALUE] - print or set configuraton variables", builtin_set },
+	{ "safe", "<COMMAND> [ARG]... - run command ignoring errors", builtin_safe },
+
+	{ "redetect", " - Redetect CPU", builtin_redetect },
+	{ "rebuildcfg", " - Rebuild firmware configuration data", builtin_rebuildcfg },
+
+	{ NULL, NULL, NULL }
+};
+
+static int builtin_help(shell_context_t *ctx, int argc, char *argv[]) {
+/*	for(int i = 0; commands[i].cmd != NULL; i++) {
+		printf("%s %s\n", commands[i].cmd, commands[i].description);
+	}
+
+	if(set_cmds) {
+		for(int i = 0; set_cmds[i].cmd != NULL; i++)
+			printf("%s %s\n", set_cmds[i].cmd, set_cmds[i].description);
+	}*/
+
+	return 0;
+}
+
+static int builtin_exit(shell_context_t *ctx, int argc, char *argv[]) {
+	shell_exit(ctx, 1);
+
+	return 0;
+}
+
+static int builtin_source(shell_context_t *ctx, int argc, char *argv[]) {
+	if(argc != 2) {
+		printf("Usage: %s <FILENAME>\n", argv[0]);
+
+		return -1;
+	}
+
+	int ret = shell_source(ctx, argv[1]);
+
+	if(ret == -1) {
+		fprintf(stderr, "Error while sourcing file %s: %s\n", argv[1], strerror(errno));
+	}
+
+	shell_exit(ctx, 0);
+
+	return ret;
+}
+
+static int builtin_echo(shell_context_t *ctx, int argc, char *argv[]) {
+	if(argc < 2) {
+		printf("Usage: %s <STRING>\n", argv[0]);
+
+		return -1;
+	}
+
+	for(int i = 1; i < argc; i++) {
+		fputs(argv[i], stdout);
+
+		putchar((i < argc - 1) ? ' ' : '\n');
+	}
+
+	return 0;
+}
+
+static int builtin_sleep(shell_context_t *ctx, int argc, char *argv[]) {
+	if(argc != 2) {
+		printf("Usage: %s <MILLISECONDS>\n", argv[0]);
+
+		return -1;
+	}
+
+	uint32_t ms = atoi(argv[1]);
+
+	usleep(ms * 1000);
+
+	return 0;
+}
+
+static int builtin_redetect(shell_context_t *ctx, int argc, char *argv[]) {
+	if(argc != 1) {
+		printf("Usage: %s\n", argv[0]);
+
+		return -1;
+	}
+
+	if(ingenic_redetect(shell_device(ctx)) == -1) {
+		perror("ingenic_redetect");
+
+		return -1;
+	} else
+		return 0;
+}
+
+
+static int builtin_set(shell_context_t *ctx, int argc, char *argv[]) {
+	if(argc == 1 && cfg_environ) {
+		for(int i = 0; cfg_environ[i] != NULL; i++)
+			printf("%s\n", cfg_environ[i]);
+
+	} else if(argc == 2) {
+		cfg_unsetenv(argv[1]);
+
+	} else if(argc == 3) {
+		cfg_setenv(argv[1], argv[2]);
+
+	} else {
+		printf("Usage: %s [VARIABLE] [VALUE]\n", argv[0]);
+
+		return -1;
+	}
+
+	return 0;
+}
+
+
+static int builtin_rebuildcfg(shell_context_t *ctx, int argc, char *argv[]) {
+	if(argc != 1) {
+		printf("Usage: %s\n", argv[0]);
+
+		return -1;
+	}
+
+	return ingenic_rebuild(shell_device(ctx));
+}
+
+static int builtin_safe(shell_context_t *ctx, int argc, char *argv[]) {
+	if(argc < 2) {
+		printf("Usage: %s <COMMAND> [ARG]...\n", argv[0]);
+
+		return -1;
+	}
+
+	if(shell_run(ctx, argc - 1, argv + 1) == -1)
+		perror("shell_run");
+
+	return 0;
+}
+
diff --git a/shell_internal.h b/shell_internal.h
new file mode 100644
index 0000000..e416c20
--- /dev/null
+++ b/shell_internal.h
@@ -0,0 +1,62 @@
+/*
+ * JzBoot: an USB bootloader for JZ series of Ingenic(R) microprocessors.
+ * Copyright (C) 2010  Sergey Gridassov <grindars@gmail.com>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef __SHELL_INTERNAL__H__
+#define __SHELL_INTERNAL__H__
+
+#define SHELL_INTERNALS
+#define STATE_WANTSTR	0
+#define STATE_WANTSPACE	1
+
+#define TOK_SEPARATOR	1
+#define TOK_STRING	2
+#define TOK_SPACE	3
+#define TOK_COMMENT	4
+
+typedef struct {
+	void *device;
+	char linebuf[512];
+	char *strval;
+	char *line;
+	const struct shell_command *set_cmds;
+	int shell_exit;
+} shell_context_t;
+
+
+typedef struct {
+	int argc;
+	char **argv;
+} shell_run_data_t;
+
+int shell_pull(shell_context_t *ctx, char *buf, int maxlen);
+
+#ifndef FLEX_SCANNER
+typedef void *yyscan_t;
+int yylex_init(yyscan_t *ptr_yy_globals);
+int yylex_init_extra(shell_context_t *user_defined, yyscan_t *ptr_yy_globals);
+int yylex(yyscan_t yyscanner) ;
+int yylex_destroy (yyscan_t yyscanner) ;
+#else
+#define YY_EXTRA_TYPE shell_context_t *
+#define YY_INPUT(buf, result, max_size) result = shell_pull(yyextra, buf, max_size);
+#endif
+
+#include "shell.h"
+
+#endif
+
diff --git a/shell_lex.c b/shell_lex.c
index eea7de3..c32427d 100644
--- a/shell_lex.c
+++ b/shell_lex.c
@@ -119,24 +119,41 @@ typedef unsigned int flex_uint32_t;
  */
 #define YY_SC_TO_UI(c) ((unsigned int) (unsigned char) c)
 
+/* An opaque pointer. */
+#ifndef YY_TYPEDEF_YY_SCANNER_T
+#define YY_TYPEDEF_YY_SCANNER_T
+typedef void* yyscan_t;
+#endif
+
+/* For convenience, these vars (plus the bison vars far below)
+   are macros in the reentrant scanner. */
+#define yyin yyg->yyin_r
+#define yyout yyg->yyout_r
+#define yyextra yyg->yyextra_r
+#define yyleng yyg->yyleng_r
+#define yytext yyg->yytext_r
+#define yylineno (YY_CURRENT_BUFFER_LVALUE->yy_bs_lineno)
+#define yycolumn (YY_CURRENT_BUFFER_LVALUE->yy_bs_column)
+#define yy_flex_debug yyg->yy_flex_debug_r
+
 /* Enter a start condition.  This macro really ought to take a parameter,
  * but we do it the disgusting crufty way forced on us by the ()-less
  * definition of BEGIN.
  */
-#define BEGIN (yy_start) = 1 + 2 *
+#define BEGIN yyg->yy_start = 1 + 2 *
 
 /* Translate the current start state into a value that can be later handed
  * to BEGIN to return to the state.  The YYSTATE alias is for lex
  * compatibility.
  */
-#define YY_START (((yy_start) - 1) / 2)
+#define YY_START ((yyg->yy_start - 1) / 2)
 #define YYSTATE YY_START
 
 /* Action number for EOF rule of a given start state. */
 #define YY_STATE_EOF(state) (YY_END_OF_BUFFER + state + 1)
 
 /* Special action meaning "start processing a new file". */
-#define YY_NEW_FILE yyrestart(yyin  )
+#define YY_NEW_FILE yyrestart(yyin ,yyscanner )
 
 #define YY_END_OF_BUFFER_CHAR 0
 
@@ -162,10 +179,6 @@ typedef unsigned int flex_uint32_t;
 typedef struct yy_buffer_state *YY_BUFFER_STATE;
 #endif
 
-extern int yyleng;
-
-extern FILE *yyin, *yyout;
-
 #define EOB_ACT_CONTINUE_SCAN 0
 #define EOB_ACT_END_OF_FILE 1
 #define EOB_ACT_LAST_MATCH 2
@@ -179,14 +192,14 @@ extern FILE *yyin, *yyout;
 		/* Undo effects of setting up yytext. */ \
         int yyless_macro_arg = (n); \
         YY_LESS_LINENO(yyless_macro_arg);\
-		*yy_cp = (yy_hold_char); \
+		*yy_cp = yyg->yy_hold_char; \
 		YY_RESTORE_YY_MORE_OFFSET \
-		(yy_c_buf_p) = yy_cp = yy_bp + yyless_macro_arg - YY_MORE_ADJ; \
+		yyg->yy_c_buf_p = yy_cp = yy_bp + yyless_macro_arg - YY_MORE_ADJ; \
 		YY_DO_BEFORE_ACTION; /* set up yytext again */ \
 		} \
 	while ( 0 )
 
-#define unput(c) yyunput( c, (yytext_ptr)  )
+#define unput(c) yyunput( c, yyg->yytext_ptr , yyscanner )
 
 #ifndef YY_TYPEDEF_YY_SIZE_T
 #define YY_TYPEDEF_YY_SIZE_T
@@ -258,71 +271,51 @@ struct yy_buffer_state
 	};
 #endif /* !YY_STRUCT_YY_BUFFER_STATE */
 
-/* Stack of input buffers. */
-static size_t yy_buffer_stack_top = 0; /**< index of top of stack. */
-static size_t yy_buffer_stack_max = 0; /**< capacity of stack. */
-static YY_BUFFER_STATE * yy_buffer_stack = 0; /**< Stack as an array. */
-
 /* We provide macros for accessing buffer states in case in the
  * future we want to put the buffer states in a more general
  * "scanner state".
  *
  * Returns the top of the stack, or NULL.
  */
-#define YY_CURRENT_BUFFER ( (yy_buffer_stack) \
-                          ? (yy_buffer_stack)[(yy_buffer_stack_top)] \
+#define YY_CURRENT_BUFFER ( yyg->yy_buffer_stack \
+                          ? yyg->yy_buffer_stack[yyg->yy_buffer_stack_top] \
                           : NULL)
 
 /* Same as previous macro, but useful when we know that the buffer stack is not
  * NULL or when we need an lvalue. For internal use only.
  */
-#define YY_CURRENT_BUFFER_LVALUE (yy_buffer_stack)[(yy_buffer_stack_top)]
+#define YY_CURRENT_BUFFER_LVALUE yyg->yy_buffer_stack[yyg->yy_buffer_stack_top]
 
-/* yy_hold_char holds the character lost when yytext is formed. */
-static char yy_hold_char;
-static int yy_n_chars;		/* number of characters read into yy_ch_buf */
-int yyleng;
+void yyrestart (FILE *input_file ,yyscan_t yyscanner );
+void yy_switch_to_buffer (YY_BUFFER_STATE new_buffer ,yyscan_t yyscanner );
+YY_BUFFER_STATE yy_create_buffer (FILE *file,int size ,yyscan_t yyscanner );
+void yy_delete_buffer (YY_BUFFER_STATE b ,yyscan_t yyscanner );
+void yy_flush_buffer (YY_BUFFER_STATE b ,yyscan_t yyscanner );
+void yypush_buffer_state (YY_BUFFER_STATE new_buffer ,yyscan_t yyscanner );
+void yypop_buffer_state (yyscan_t yyscanner );
 
-/* Points to current character in buffer. */
-static char *yy_c_buf_p = (char *) 0;
-static int yy_init = 0;		/* whether we need to initialize */
-static int yy_start = 0;	/* start state number */
+static void yyensure_buffer_stack (yyscan_t yyscanner );
+static void yy_load_buffer_state (yyscan_t yyscanner );
+static void yy_init_buffer (YY_BUFFER_STATE b,FILE *file ,yyscan_t yyscanner );
 
-/* Flag which is used to allow yywrap()'s to do buffer switches
- * instead of setting up a fresh yyin.  A bit of a hack ...
- */
-static int yy_did_buffer_switch_on_eof;
+#define YY_FLUSH_BUFFER yy_flush_buffer(YY_CURRENT_BUFFER ,yyscanner)
 
-void yyrestart (FILE *input_file  );
-void yy_switch_to_buffer (YY_BUFFER_STATE new_buffer  );
-YY_BUFFER_STATE yy_create_buffer (FILE *file,int size  );
-void yy_delete_buffer (YY_BUFFER_STATE b  );
-void yy_flush_buffer (YY_BUFFER_STATE b  );
-void yypush_buffer_state (YY_BUFFER_STATE new_buffer  );
-void yypop_buffer_state (void );
+YY_BUFFER_STATE yy_scan_buffer (char *base,yy_size_t size ,yyscan_t yyscanner );
+YY_BUFFER_STATE yy_scan_string (yyconst char *yy_str ,yyscan_t yyscanner );
+YY_BUFFER_STATE yy_scan_bytes (yyconst char *bytes,int len ,yyscan_t yyscanner );
 
-static void yyensure_buffer_stack (void );
-static void yy_load_buffer_state (void );
-static void yy_init_buffer (YY_BUFFER_STATE b,FILE *file  );
-
-#define YY_FLUSH_BUFFER yy_flush_buffer(YY_CURRENT_BUFFER )
-
-YY_BUFFER_STATE yy_scan_buffer (char *base,yy_size_t size  );
-YY_BUFFER_STATE yy_scan_string (yyconst char *yy_str  );
-YY_BUFFER_STATE yy_scan_bytes (yyconst char *bytes,int len  );
-
-void *yyalloc (yy_size_t  );
-void *yyrealloc (void *,yy_size_t  );
-void yyfree (void *  );
+void *yyalloc (yy_size_t ,yyscan_t yyscanner );
+void *yyrealloc (void *,yy_size_t ,yyscan_t yyscanner );
+void yyfree (void * ,yyscan_t yyscanner );
 
 #define yy_new_buffer yy_create_buffer
 
 #define yy_set_interactive(is_interactive) \
 	{ \
 	if ( ! YY_CURRENT_BUFFER ){ \
-        yyensure_buffer_stack (); \
+        yyensure_buffer_stack (yyscanner); \
 		YY_CURRENT_BUFFER_LVALUE =    \
-            yy_create_buffer(yyin,YY_BUF_SIZE ); \
+            yy_create_buffer(yyin,YY_BUF_SIZE ,yyscanner); \
 	} \
 	YY_CURRENT_BUFFER_LVALUE->yy_is_interactive = is_interactive; \
 	}
@@ -330,9 +323,9 @@ void yyfree (void *  );
 #define yy_set_bol(at_bol) \
 	{ \
 	if ( ! YY_CURRENT_BUFFER ){\
-        yyensure_buffer_stack (); \
+        yyensure_buffer_stack (yyscanner); \
 		YY_CURRENT_BUFFER_LVALUE =    \
-            yy_create_buffer(yyin,YY_BUF_SIZE ); \
+            yy_create_buffer(yyin,YY_BUF_SIZE ,yyscanner); \
 	} \
 	YY_CURRENT_BUFFER_LVALUE->yy_at_bol = at_bol; \
 	}
@@ -344,31 +337,24 @@ void yyfree (void *  );
 
 typedef unsigned char YY_CHAR;
 
-FILE *yyin = (FILE *) 0, *yyout = (FILE *) 0;
-
 typedef int yy_state_type;
 
-extern int yylineno;
+#define yytext_ptr yytext_r
 
-int yylineno = 1;
-
-extern char *yytext;
-#define yytext_ptr yytext
-
-static yy_state_type yy_get_previous_state (void );
-static yy_state_type yy_try_NUL_trans (yy_state_type current_state  );
-static int yy_get_next_buffer (void );
-static void yy_fatal_error (yyconst char msg[]  );
+static yy_state_type yy_get_previous_state (yyscan_t yyscanner );
+static yy_state_type yy_try_NUL_trans (yy_state_type current_state  ,yyscan_t yyscanner);
+static int yy_get_next_buffer (yyscan_t yyscanner );
+static void yy_fatal_error (yyconst char msg[] ,yyscan_t yyscanner );
 
 /* Done after the current pattern has been matched and before the
  * corresponding action - sets up yytext.
  */
 #define YY_DO_BEFORE_ACTION \
-	(yytext_ptr) = yy_bp; \
+	yyg->yytext_ptr = yy_bp; \
 	yyleng = (size_t) (yy_cp - yy_bp); \
-	(yy_hold_char) = *yy_cp; \
+	yyg->yy_hold_char = *yy_cp; \
 	*yy_cp = '\0'; \
-	(yy_c_buf_p) = yy_cp;
+	yyg->yy_c_buf_p = yy_cp;
 
 #define YY_NUM_RULES 10
 #define YY_END_OF_BUFFER 11
@@ -452,12 +438,6 @@ static yyconst flex_int16_t yy_chk[36] =
        18,   18,   18,   18,   18
     } ;
 
-static yy_state_type yy_last_accepting_state;
-static char *yy_last_accepting_cpos;
-
-extern int yy_flex_debug;
-int yy_flex_debug = 0;
-
 /* The intent behind this definition is that it'll catch
  * any uses of REJECT which flex missed.
  */
@@ -465,7 +445,6 @@ int yy_flex_debug = 0;
 #define yymore() yymore_used_but_not_detected
 #define YY_MORE_ADJ 0
 #define YY_RESTORE_YY_MORE_OFFSET
-char *yytext;
 #line 1 "shell_lex.l"
 /*
  * JzBoot: an USB bootloader for JZ series of Ingenic(R) microprocessors.
@@ -485,12 +464,10 @@ char *yytext;
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 #line 20 "shell_lex.l"
-#include "shell.h"
+#include "shell_internal.h"
 #include <string.h>
 #include <stdlib.h>
 
-#define YY_INPUT(buf, result, max_size) result = shell_pull(buf, max_size);
-
 static char *str_append(char *str, const char *src) {
 	if(str) {
 		size_t newlen = strlen(str) + strlen(src) + 1;
@@ -508,7 +485,7 @@ static char *str_append(char *str, const char *src) {
 }
 #define YY_NO_INPUT 1
 
-#line 512 "shell_lex.c"
+#line 489 "shell_lex.c"
 
 #define INITIAL 0
 #define STR 1
@@ -525,36 +502,74 @@ static char *str_append(char *str, const char *src) {
 #define YY_EXTRA_TYPE void *
 #endif
 
-static int yy_init_globals (void );
+/* Holds the entire state of the reentrant scanner. */
+struct yyguts_t
+    {
+
+    /* User-defined. Not touched by flex. */
+    YY_EXTRA_TYPE yyextra_r;
+
+    /* The rest are the same as the globals declared in the non-reentrant scanner. */
+    FILE *yyin_r, *yyout_r;
+    size_t yy_buffer_stack_top; /**< index of top of stack. */
+    size_t yy_buffer_stack_max; /**< capacity of stack. */
+    YY_BUFFER_STATE * yy_buffer_stack; /**< Stack as an array. */
+    char yy_hold_char;
+    int yy_n_chars;
+    int yyleng_r;
+    char *yy_c_buf_p;
+    int yy_init;
+    int yy_start;
+    int yy_did_buffer_switch_on_eof;
+    int yy_start_stack_ptr;
+    int yy_start_stack_depth;
+    int *yy_start_stack;
+    yy_state_type yy_last_accepting_state;
+    char* yy_last_accepting_cpos;
+
+    int yylineno_r;
+    int yy_flex_debug_r;
+
+    char *yytext_r;
+    int yy_more_flag;
+    int yy_more_len;
+
+    }; /* end struct yyguts_t */
+
+static int yy_init_globals (yyscan_t yyscanner );
+
+int yylex_init (yyscan_t* scanner);
+
+int yylex_init_extra (YY_EXTRA_TYPE user_defined,yyscan_t* scanner);
 
 /* Accessor methods to globals.
    These are made visible to non-reentrant scanners for convenience. */
 
-int yylex_destroy (void );
+int yylex_destroy (yyscan_t yyscanner );
 
-int yyget_debug (void );
+int yyget_debug (yyscan_t yyscanner );
 
-void yyset_debug (int debug_flag  );
+void yyset_debug (int debug_flag ,yyscan_t yyscanner );
 
-YY_EXTRA_TYPE yyget_extra (void );
+YY_EXTRA_TYPE yyget_extra (yyscan_t yyscanner );
 
-void yyset_extra (YY_EXTRA_TYPE user_defined  );
+void yyset_extra (YY_EXTRA_TYPE user_defined ,yyscan_t yyscanner );
 
-FILE *yyget_in (void );
+FILE *yyget_in (yyscan_t yyscanner );
 
-void yyset_in  (FILE * in_str  );
+void yyset_in  (FILE * in_str ,yyscan_t yyscanner );
 
-FILE *yyget_out (void );
+FILE *yyget_out (yyscan_t yyscanner );
 
-void yyset_out  (FILE * out_str  );
+void yyset_out  (FILE * out_str ,yyscan_t yyscanner );
 
-int yyget_leng (void );
+int yyget_leng (yyscan_t yyscanner );
 
-char *yyget_text (void );
+char *yyget_text (yyscan_t yyscanner );
 
-int yyget_lineno (void );
+int yyget_lineno (yyscan_t yyscanner );
 
-void yyset_lineno (int line_number  );
+void yyset_lineno (int line_number ,yyscan_t yyscanner );
 
 /* Macros after this point can all be overridden by user definitions in
  * section 1.
@@ -562,26 +577,26 @@ void yyset_lineno (int line_number  );
 
 #ifndef YY_SKIP_YYWRAP
 #ifdef __cplusplus
-extern "C" int yywrap (void );
+extern "C" int yywrap (yyscan_t yyscanner );
 #else
-extern int yywrap (void );
+extern int yywrap (yyscan_t yyscanner );
 #endif
 #endif
 
 #ifndef yytext_ptr
-static void yy_flex_strncpy (char *,yyconst char *,int );
+static void yy_flex_strncpy (char *,yyconst char *,int ,yyscan_t yyscanner);
 #endif
 
 #ifdef YY_NEED_STRLEN
-static int yy_flex_strlen (yyconst char * );
+static int yy_flex_strlen (yyconst char * ,yyscan_t yyscanner);
 #endif
 
 #ifndef YY_NO_INPUT
 
 #ifdef __cplusplus
-static int yyinput (void );
+static int yyinput (yyscan_t yyscanner );
 #else
-static int input (void );
+static int input (yyscan_t yyscanner );
 #endif
 
 #endif
@@ -655,7 +670,7 @@ static int input (void );
 
 /* Report a fatal error. */
 #ifndef YY_FATAL_ERROR
-#define YY_FATAL_ERROR(msg) yy_fatal_error( msg )
+#define YY_FATAL_ERROR(msg) yy_fatal_error( msg , yyscanner)
 #endif
 
 /* end tables serialization structures and prototypes */
@@ -666,9 +681,9 @@ static int input (void );
 #ifndef YY_DECL
 #define YY_DECL_IS_OURS 1
 
-extern int yylex (void);
+extern int yylex (yyscan_t yyscanner);
 
-#define YY_DECL int yylex (void)
+#define YY_DECL int yylex (yyscan_t yyscanner)
 #endif /* !YY_DECL */
 
 /* Code executed at the beginning of each rule, after yytext and yyleng
@@ -693,21 +708,22 @@ YY_DECL
 	register yy_state_type yy_current_state;
 	register char *yy_cp, *yy_bp;
 	register int yy_act;
-    
-#line 45 "shell_lex.l"
+    struct yyguts_t * yyg = (struct yyguts_t*)yyscanner;
 
-#line 700 "shell_lex.c"
+#line 43 "shell_lex.l"
 
-	if ( !(yy_init) )
+#line 716 "shell_lex.c"
+
+	if ( !yyg->yy_init )
 		{
-		(yy_init) = 1;
+		yyg->yy_init = 1;
 
 #ifdef YY_USER_INIT
 		YY_USER_INIT;
 #endif
 
-		if ( ! (yy_start) )
-			(yy_start) = 1;	/* first start state */
+		if ( ! yyg->yy_start )
+			yyg->yy_start = 1;	/* first start state */
 
 		if ( ! yyin )
 			yyin = stdin;
@@ -716,35 +732,35 @@ YY_DECL
 			yyout = stdout;
 
 		if ( ! YY_CURRENT_BUFFER ) {
-			yyensure_buffer_stack ();
+			yyensure_buffer_stack (yyscanner);
 			YY_CURRENT_BUFFER_LVALUE =
-				yy_create_buffer(yyin,YY_BUF_SIZE );
+				yy_create_buffer(yyin,YY_BUF_SIZE ,yyscanner);
 		}
 
-		yy_load_buffer_state( );
+		yy_load_buffer_state(yyscanner );
 		}
 
 	while ( 1 )		/* loops until end-of-file is reached */
 		{
-		yy_cp = (yy_c_buf_p);
+		yy_cp = yyg->yy_c_buf_p;
 
 		/* Support of yytext. */
-		*yy_cp = (yy_hold_char);
+		*yy_cp = yyg->yy_hold_char;
 
 		/* yy_bp points to the position in yy_ch_buf of the start of
 		 * the current run.
 		 */
 		yy_bp = yy_cp;
 
-		yy_current_state = (yy_start);
+		yy_current_state = yyg->yy_start;
 yy_match:
 		do
 			{
 			register YY_CHAR yy_c = yy_ec[YY_SC_TO_UI(*yy_cp)];
 			if ( yy_accept[yy_current_state] )
 				{
-				(yy_last_accepting_state) = yy_current_state;
-				(yy_last_accepting_cpos) = yy_cp;
+				yyg->yy_last_accepting_state = yy_current_state;
+				yyg->yy_last_accepting_cpos = yy_cp;
 				}
 			while ( yy_chk[yy_base[yy_current_state] + yy_c] != yy_current_state )
 				{
@@ -756,8 +772,8 @@ yy_match:
 			++yy_cp;
 			}
 		while ( yy_current_state != 18 );
-		yy_cp = (yy_last_accepting_cpos);
-		yy_current_state = (yy_last_accepting_state);
+		yy_cp = yyg->yy_last_accepting_cpos;
+		yy_current_state = yyg->yy_last_accepting_state;
 
 yy_find_action:
 		yy_act = yy_accept[yy_current_state];
@@ -770,64 +786,64 @@ do_action:	/* This label is used only to access EOF actions. */
 	{ /* beginning of action switch */
 			case 0: /* must back up */
 			/* undo the effects of YY_DO_BEFORE_ACTION */
-			*yy_cp = (yy_hold_char);
-			yy_cp = (yy_last_accepting_cpos);
-			yy_current_state = (yy_last_accepting_state);
+			*yy_cp = yyg->yy_hold_char;
+			yy_cp = yyg->yy_last_accepting_cpos;
+			yy_current_state = yyg->yy_last_accepting_state;
 			goto yy_find_action;
 
 case 1:
 YY_RULE_SETUP
-#line 46 "shell_lex.l"
-{ strval = NULL; BEGIN(STR); }
+#line 44 "shell_lex.l"
+{ yyextra->strval = NULL; BEGIN(STR); }
 	YY_BREAK
 case 2:
 YY_RULE_SETUP
-#line 47 "shell_lex.l"
+#line 45 "shell_lex.l"
 return TOK_SEPARATOR;
 	YY_BREAK
 case 3:
 /* rule 3 can match eol */
 YY_RULE_SETUP
-#line 48 "shell_lex.l"
+#line 46 "shell_lex.l"
 return TOK_SPACE;
 	YY_BREAK
 case 4:
 YY_RULE_SETUP
-#line 49 "shell_lex.l"
+#line 47 "shell_lex.l"
 return TOK_COMMENT;
 	YY_BREAK
 case 5:
 YY_RULE_SETUP
-#line 50 "shell_lex.l"
-{ strval = strdup(yytext); return TOK_STRING; }
+#line 48 "shell_lex.l"
+{ yyextra->strval = strdup(yytext); return TOK_STRING; }
 	YY_BREAK
 case 6:
 /* rule 6 can match eol */
 YY_RULE_SETUP
-#line 51 "shell_lex.l"
-strval = str_append(strval, yytext);
+#line 49 "shell_lex.l"
+yyextra->strval = str_append(yyextra->strval, yytext);
 	YY_BREAK
 case 7:
 YY_RULE_SETUP
-#line 52 "shell_lex.l"
-strval = str_append(strval, "\"");
+#line 50 "shell_lex.l"
+yyextra->strval = str_append(yyextra->strval, "\"");
 	YY_BREAK
 case 8:
 YY_RULE_SETUP
-#line 53 "shell_lex.l"
-strval = str_append(strval, "\\");
+#line 51 "shell_lex.l"
+yyextra->strval = str_append(yyextra->strval, "\\");
 	YY_BREAK
 case 9:
 YY_RULE_SETUP
-#line 54 "shell_lex.l"
+#line 52 "shell_lex.l"
 { BEGIN(INITIAL); return TOK_STRING; }
 	YY_BREAK
 case 10:
 YY_RULE_SETUP
-#line 55 "shell_lex.l"
+#line 53 "shell_lex.l"
 ECHO;
 	YY_BREAK
-#line 831 "shell_lex.c"
+#line 847 "shell_lex.c"
 case YY_STATE_EOF(INITIAL):
 case YY_STATE_EOF(STR):
 	yyterminate();
@@ -835,10 +851,10 @@ case YY_STATE_EOF(STR):
 	case YY_END_OF_BUFFER:
 		{
 		/* Amount of text matched not including the EOB char. */
-		int yy_amount_of_matched_text = (int) (yy_cp - (yytext_ptr)) - 1;
+		int yy_amount_of_matched_text = (int) (yy_cp - yyg->yytext_ptr) - 1;
 
 		/* Undo the effects of YY_DO_BEFORE_ACTION. */
-		*yy_cp = (yy_hold_char);
+		*yy_cp = yyg->yy_hold_char;
 		YY_RESTORE_YY_MORE_OFFSET
 
 		if ( YY_CURRENT_BUFFER_LVALUE->yy_buffer_status == YY_BUFFER_NEW )
@@ -852,7 +868,7 @@ case YY_STATE_EOF(STR):
 			 * this is the first action (other than possibly a
 			 * back-up) that will match for the new input source.
 			 */
-			(yy_n_chars) = YY_CURRENT_BUFFER_LVALUE->yy_n_chars;
+			yyg->yy_n_chars = YY_CURRENT_BUFFER_LVALUE->yy_n_chars;
 			YY_CURRENT_BUFFER_LVALUE->yy_input_file = yyin;
 			YY_CURRENT_BUFFER_LVALUE->yy_buffer_status = YY_BUFFER_NORMAL;
 			}
@@ -864,13 +880,13 @@ case YY_STATE_EOF(STR):
 		 * end-of-buffer state).  Contrast this with the test
 		 * in input().
 		 */
-		if ( (yy_c_buf_p) <= &YY_CURRENT_BUFFER_LVALUE->yy_ch_buf[(yy_n_chars)] )
+		if ( yyg->yy_c_buf_p <= &YY_CURRENT_BUFFER_LVALUE->yy_ch_buf[yyg->yy_n_chars] )
 			{ /* This was really a NUL. */
 			yy_state_type yy_next_state;
 
-			(yy_c_buf_p) = (yytext_ptr) + yy_amount_of_matched_text;
+			yyg->yy_c_buf_p = yyg->yytext_ptr + yy_amount_of_matched_text;
 
-			yy_current_state = yy_get_previous_state(  );
+			yy_current_state = yy_get_previous_state( yyscanner );
 
 			/* Okay, we're now positioned to make the NUL
 			 * transition.  We couldn't have
@@ -881,33 +897,33 @@ case YY_STATE_EOF(STR):
 			 * will run more slowly).
 			 */
 
-			yy_next_state = yy_try_NUL_trans( yy_current_state );
+			yy_next_state = yy_try_NUL_trans( yy_current_state , yyscanner);
 
-			yy_bp = (yytext_ptr) + YY_MORE_ADJ;
+			yy_bp = yyg->yytext_ptr + YY_MORE_ADJ;
 
 			if ( yy_next_state )
 				{
 				/* Consume the NUL. */
-				yy_cp = ++(yy_c_buf_p);
+				yy_cp = ++yyg->yy_c_buf_p;
 				yy_current_state = yy_next_state;
 				goto yy_match;
 				}
 
 			else
 				{
-				yy_cp = (yy_last_accepting_cpos);
-				yy_current_state = (yy_last_accepting_state);
+				yy_cp = yyg->yy_last_accepting_cpos;
+				yy_current_state = yyg->yy_last_accepting_state;
 				goto yy_find_action;
 				}
 			}
 
-		else switch ( yy_get_next_buffer(  ) )
+		else switch ( yy_get_next_buffer( yyscanner ) )
 			{
 			case EOB_ACT_END_OF_FILE:
 				{
-				(yy_did_buffer_switch_on_eof) = 0;
+				yyg->yy_did_buffer_switch_on_eof = 0;
 
-				if ( yywrap( ) )
+				if ( yywrap(yyscanner ) )
 					{
 					/* Note: because we've taken care in
 					 * yy_get_next_buffer() to have set up
@@ -918,7 +934,7 @@ case YY_STATE_EOF(STR):
 					 * YY_NULL, it'll still work - another
 					 * YY_NULL will get returned.
 					 */
-					(yy_c_buf_p) = (yytext_ptr) + YY_MORE_ADJ;
+					yyg->yy_c_buf_p = yyg->yytext_ptr + YY_MORE_ADJ;
 
 					yy_act = YY_STATE_EOF(YY_START);
 					goto do_action;
@@ -926,30 +942,30 @@ case YY_STATE_EOF(STR):
 
 				else
 					{
-					if ( ! (yy_did_buffer_switch_on_eof) )
+					if ( ! yyg->yy_did_buffer_switch_on_eof )
 						YY_NEW_FILE;
 					}
 				break;
 				}
 
 			case EOB_ACT_CONTINUE_SCAN:
-				(yy_c_buf_p) =
-					(yytext_ptr) + yy_amount_of_matched_text;
+				yyg->yy_c_buf_p =
+					yyg->yytext_ptr + yy_amount_of_matched_text;
 
-				yy_current_state = yy_get_previous_state(  );
+				yy_current_state = yy_get_previous_state( yyscanner );
 
-				yy_cp = (yy_c_buf_p);
-				yy_bp = (yytext_ptr) + YY_MORE_ADJ;
+				yy_cp = yyg->yy_c_buf_p;
+				yy_bp = yyg->yytext_ptr + YY_MORE_ADJ;
 				goto yy_match;
 
 			case EOB_ACT_LAST_MATCH:
-				(yy_c_buf_p) =
-				&YY_CURRENT_BUFFER_LVALUE->yy_ch_buf[(yy_n_chars)];
+				yyg->yy_c_buf_p =
+				&YY_CURRENT_BUFFER_LVALUE->yy_ch_buf[yyg->yy_n_chars];
 
-				yy_current_state = yy_get_previous_state(  );
+				yy_current_state = yy_get_previous_state( yyscanner );
 
-				yy_cp = (yy_c_buf_p);
-				yy_bp = (yytext_ptr) + YY_MORE_ADJ;
+				yy_cp = yyg->yy_c_buf_p;
+				yy_bp = yyg->yytext_ptr + YY_MORE_ADJ;
 				goto yy_find_action;
 			}
 		break;
@@ -969,20 +985,21 @@ case YY_STATE_EOF(STR):
  *	EOB_ACT_CONTINUE_SCAN - continue scanning from current position
  *	EOB_ACT_END_OF_FILE - end of file
  */
-static int yy_get_next_buffer (void)
+static int yy_get_next_buffer (yyscan_t yyscanner)
 {
-    	register char *dest = YY_CURRENT_BUFFER_LVALUE->yy_ch_buf;
-	register char *source = (yytext_ptr);
+    struct yyguts_t * yyg = (struct yyguts_t*)yyscanner;
+	register char *dest = YY_CURRENT_BUFFER_LVALUE->yy_ch_buf;
+	register char *source = yyg->yytext_ptr;
 	register int number_to_move, i;
 	int ret_val;
 
-	if ( (yy_c_buf_p) > &YY_CURRENT_BUFFER_LVALUE->yy_ch_buf[(yy_n_chars) + 1] )
+	if ( yyg->yy_c_buf_p > &YY_CURRENT_BUFFER_LVALUE->yy_ch_buf[yyg->yy_n_chars + 1] )
 		YY_FATAL_ERROR(
 		"fatal flex scanner internal error--end of buffer missed" );
 
 	if ( YY_CURRENT_BUFFER_LVALUE->yy_fill_buffer == 0 )
 		{ /* Don't try to fill the buffer, so this is an EOF. */
-		if ( (yy_c_buf_p) - (yytext_ptr) - YY_MORE_ADJ == 1 )
+		if ( yyg->yy_c_buf_p - yyg->yytext_ptr - YY_MORE_ADJ == 1 )
 			{
 			/* We matched a single character, the EOB, so
 			 * treat this as a final EOF.
@@ -1002,7 +1019,7 @@ static int yy_get_next_buffer (void)
 	/* Try to read more data. */
 
 	/* First move last chars to start of buffer. */
-	number_to_move = (int) ((yy_c_buf_p) - (yytext_ptr)) - 1;
+	number_to_move = (int) (yyg->yy_c_buf_p - yyg->yytext_ptr) - 1;
 
 	for ( i = 0; i < number_to_move; ++i )
 		*(dest++) = *(source++);
@@ -1011,7 +1028,7 @@ static int yy_get_next_buffer (void)
 		/* don't do the read, it's not guaranteed to return an EOF,
 		 * just force an EOF
 		 */
-		YY_CURRENT_BUFFER_LVALUE->yy_n_chars = (yy_n_chars) = 0;
+		YY_CURRENT_BUFFER_LVALUE->yy_n_chars = yyg->yy_n_chars = 0;
 
 	else
 		{
@@ -1025,7 +1042,7 @@ static int yy_get_next_buffer (void)
 			YY_BUFFER_STATE b = YY_CURRENT_BUFFER;
 
 			int yy_c_buf_p_offset =
-				(int) ((yy_c_buf_p) - b->yy_ch_buf);
+				(int) (yyg->yy_c_buf_p - b->yy_ch_buf);
 
 			if ( b->yy_is_our_buffer )
 				{
@@ -1038,7 +1055,7 @@ static int yy_get_next_buffer (void)
 
 				b->yy_ch_buf = (char *)
 					/* Include room in for 2 EOB chars. */
-					yyrealloc((void *) b->yy_ch_buf,b->yy_buf_size + 2  );
+					yyrealloc((void *) b->yy_ch_buf,b->yy_buf_size + 2 ,yyscanner );
 				}
 			else
 				/* Can't grow it, we don't own it. */
@@ -1048,7 +1065,7 @@ static int yy_get_next_buffer (void)
 				YY_FATAL_ERROR(
 				"fatal error - scanner input buffer overflow" );
 
-			(yy_c_buf_p) = &b->yy_ch_buf[yy_c_buf_p_offset];
+			yyg->yy_c_buf_p = &b->yy_ch_buf[yy_c_buf_p_offset];
 
 			num_to_read = YY_CURRENT_BUFFER_LVALUE->yy_buf_size -
 						number_to_move - 1;
@@ -1060,17 +1077,17 @@ static int yy_get_next_buffer (void)
 
 		/* Read in more data. */
 		YY_INPUT( (&YY_CURRENT_BUFFER_LVALUE->yy_ch_buf[number_to_move]),
-			(yy_n_chars), (size_t) num_to_read );
+			yyg->yy_n_chars, (size_t) num_to_read );
 
-		YY_CURRENT_BUFFER_LVALUE->yy_n_chars = (yy_n_chars);
+		YY_CURRENT_BUFFER_LVALUE->yy_n_chars = yyg->yy_n_chars;
 		}
 
-	if ( (yy_n_chars) == 0 )
+	if ( yyg->yy_n_chars == 0 )
 		{
 		if ( number_to_move == YY_MORE_ADJ )
 			{
 			ret_val = EOB_ACT_END_OF_FILE;
-			yyrestart(yyin  );
+			yyrestart(yyin  ,yyscanner);
 			}
 
 		else
@@ -1084,39 +1101,40 @@ static int yy_get_next_buffer (void)
 	else
 		ret_val = EOB_ACT_CONTINUE_SCAN;
 
-	if ((yy_size_t) ((yy_n_chars) + number_to_move) > YY_CURRENT_BUFFER_LVALUE->yy_buf_size) {
+	if ((yy_size_t) (yyg->yy_n_chars + number_to_move) > YY_CURRENT_BUFFER_LVALUE->yy_buf_size) {
 		/* Extend the array by 50%, plus the number we really need. */
-		yy_size_t new_size = (yy_n_chars) + number_to_move + ((yy_n_chars) >> 1);
-		YY_CURRENT_BUFFER_LVALUE->yy_ch_buf = (char *) yyrealloc((void *) YY_CURRENT_BUFFER_LVALUE->yy_ch_buf,new_size  );
+		yy_size_t new_size = yyg->yy_n_chars + number_to_move + (yyg->yy_n_chars >> 1);
+		YY_CURRENT_BUFFER_LVALUE->yy_ch_buf = (char *) yyrealloc((void *) YY_CURRENT_BUFFER_LVALUE->yy_ch_buf,new_size ,yyscanner );
 		if ( ! YY_CURRENT_BUFFER_LVALUE->yy_ch_buf )
 			YY_FATAL_ERROR( "out of dynamic memory in yy_get_next_buffer()" );
 	}
 
-	(yy_n_chars) += number_to_move;
-	YY_CURRENT_BUFFER_LVALUE->yy_ch_buf[(yy_n_chars)] = YY_END_OF_BUFFER_CHAR;
-	YY_CURRENT_BUFFER_LVALUE->yy_ch_buf[(yy_n_chars) + 1] = YY_END_OF_BUFFER_CHAR;
+	yyg->yy_n_chars += number_to_move;
+	YY_CURRENT_BUFFER_LVALUE->yy_ch_buf[yyg->yy_n_chars] = YY_END_OF_BUFFER_CHAR;
+	YY_CURRENT_BUFFER_LVALUE->yy_ch_buf[yyg->yy_n_chars + 1] = YY_END_OF_BUFFER_CHAR;
 
-	(yytext_ptr) = &YY_CURRENT_BUFFER_LVALUE->yy_ch_buf[0];
+	yyg->yytext_ptr = &YY_CURRENT_BUFFER_LVALUE->yy_ch_buf[0];
 
 	return ret_val;
 }
 
 /* yy_get_previous_state - get the state just before the EOB char was reached */
 
-    static yy_state_type yy_get_previous_state (void)
+    static yy_state_type yy_get_previous_state (yyscan_t yyscanner)
 {
 	register yy_state_type yy_current_state;
 	register char *yy_cp;
-    
-	yy_current_state = (yy_start);
+    struct yyguts_t * yyg = (struct yyguts_t*)yyscanner;
 
-	for ( yy_cp = (yytext_ptr) + YY_MORE_ADJ; yy_cp < (yy_c_buf_p); ++yy_cp )
+	yy_current_state = yyg->yy_start;
+
+	for ( yy_cp = yyg->yytext_ptr + YY_MORE_ADJ; yy_cp < yyg->yy_c_buf_p; ++yy_cp )
 		{
 		register YY_CHAR yy_c = (*yy_cp ? yy_ec[YY_SC_TO_UI(*yy_cp)] : 1);
 		if ( yy_accept[yy_current_state] )
 			{
-			(yy_last_accepting_state) = yy_current_state;
-			(yy_last_accepting_cpos) = yy_cp;
+			yyg->yy_last_accepting_state = yy_current_state;
+			yyg->yy_last_accepting_cpos = yy_cp;
 			}
 		while ( yy_chk[yy_base[yy_current_state] + yy_c] != yy_current_state )
 			{
@@ -1135,16 +1153,17 @@ static int yy_get_next_buffer (void)
  * synopsis
  *	next_state = yy_try_NUL_trans( current_state );
  */
-    static yy_state_type yy_try_NUL_trans  (yy_state_type yy_current_state )
+    static yy_state_type yy_try_NUL_trans  (yy_state_type yy_current_state , yyscan_t yyscanner)
 {
 	register int yy_is_jam;
-    	register char *yy_cp = (yy_c_buf_p);
+    struct yyguts_t * yyg = (struct yyguts_t*)yyscanner; /* This var may be unused depending upon options. */
+	register char *yy_cp = yyg->yy_c_buf_p;
 
 	register YY_CHAR yy_c = 1;
 	if ( yy_accept[yy_current_state] )
 		{
-		(yy_last_accepting_state) = yy_current_state;
-		(yy_last_accepting_cpos) = yy_cp;
+		yyg->yy_last_accepting_state = yy_current_state;
+		yyg->yy_last_accepting_cpos = yy_cp;
 		}
 	while ( yy_chk[yy_base[yy_current_state] + yy_c] != yy_current_state )
 		{
@@ -1160,32 +1179,33 @@ static int yy_get_next_buffer (void)
 
 #ifndef YY_NO_INPUT
 #ifdef __cplusplus
-    static int yyinput (void)
+    static int yyinput (yyscan_t yyscanner)
 #else
-    static int input  (void)
+    static int input  (yyscan_t yyscanner)
 #endif
 
 {
 	int c;
-    
-	*(yy_c_buf_p) = (yy_hold_char);
+    struct yyguts_t * yyg = (struct yyguts_t*)yyscanner;
 
-	if ( *(yy_c_buf_p) == YY_END_OF_BUFFER_CHAR )
+	*yyg->yy_c_buf_p = yyg->yy_hold_char;
+
+	if ( *yyg->yy_c_buf_p == YY_END_OF_BUFFER_CHAR )
 		{
 		/* yy_c_buf_p now points to the character we want to return.
 		 * If this occurs *before* the EOB characters, then it's a
 		 * valid NUL; if not, then we've hit the end of the buffer.
 		 */
-		if ( (yy_c_buf_p) < &YY_CURRENT_BUFFER_LVALUE->yy_ch_buf[(yy_n_chars)] )
+		if ( yyg->yy_c_buf_p < &YY_CURRENT_BUFFER_LVALUE->yy_ch_buf[yyg->yy_n_chars] )
 			/* This was really a NUL. */
-			*(yy_c_buf_p) = '\0';
+			*yyg->yy_c_buf_p = '\0';
 
 		else
 			{ /* need more input */
-			int offset = (yy_c_buf_p) - (yytext_ptr);
-			++(yy_c_buf_p);
+			int offset = yyg->yy_c_buf_p - yyg->yytext_ptr;
+			++yyg->yy_c_buf_p;
 
-			switch ( yy_get_next_buffer(  ) )
+			switch ( yy_get_next_buffer( yyscanner ) )
 				{
 				case EOB_ACT_LAST_MATCH:
 					/* This happens because yy_g_n_b()
@@ -1199,34 +1219,34 @@ static int yy_get_next_buffer (void)
 					 */
 
 					/* Reset buffer status. */
-					yyrestart(yyin );
+					yyrestart(yyin ,yyscanner);
 
 					/*FALLTHROUGH*/
 
 				case EOB_ACT_END_OF_FILE:
 					{
-					if ( yywrap( ) )
+					if ( yywrap(yyscanner ) )
 						return EOF;
 
-					if ( ! (yy_did_buffer_switch_on_eof) )
+					if ( ! yyg->yy_did_buffer_switch_on_eof )
 						YY_NEW_FILE;
 #ifdef __cplusplus
-					return yyinput();
+					return yyinput(yyscanner);
 #else
-					return input();
+					return input(yyscanner);
 #endif
 					}
 
 				case EOB_ACT_CONTINUE_SCAN:
-					(yy_c_buf_p) = (yytext_ptr) + offset;
+					yyg->yy_c_buf_p = yyg->yytext_ptr + offset;
 					break;
 				}
 			}
 		}
 
-	c = *(unsigned char *) (yy_c_buf_p);	/* cast for 8-bit char's */
-	*(yy_c_buf_p) = '\0';	/* preserve yytext */
-	(yy_hold_char) = *++(yy_c_buf_p);
+	c = *(unsigned char *) yyg->yy_c_buf_p;	/* cast for 8-bit char's */
+	*yyg->yy_c_buf_p = '\0';	/* preserve yytext */
+	yyg->yy_hold_char = *++yyg->yy_c_buf_p;
 
 	return c;
 }
@@ -1234,76 +1254,79 @@ static int yy_get_next_buffer (void)
 
 /** Immediately switch to a different input stream.
  * @param input_file A readable stream.
- * 
+ * @param yyscanner The scanner object.
  * @note This function does not reset the start condition to @c INITIAL .
  */
-    void yyrestart  (FILE * input_file )
+    void yyrestart  (FILE * input_file , yyscan_t yyscanner)
 {
-    
+    struct yyguts_t * yyg = (struct yyguts_t*)yyscanner;
+
 	if ( ! YY_CURRENT_BUFFER ){
-        yyensure_buffer_stack ();
+        yyensure_buffer_stack (yyscanner);
 		YY_CURRENT_BUFFER_LVALUE =
-            yy_create_buffer(yyin,YY_BUF_SIZE );
+            yy_create_buffer(yyin,YY_BUF_SIZE ,yyscanner);
 	}
 
-	yy_init_buffer(YY_CURRENT_BUFFER,input_file );
-	yy_load_buffer_state( );
+	yy_init_buffer(YY_CURRENT_BUFFER,input_file ,yyscanner);
+	yy_load_buffer_state(yyscanner );
 }
 
 /** Switch to a different input buffer.
  * @param new_buffer The new input buffer.
- * 
+ * @param yyscanner The scanner object.
  */
-    void yy_switch_to_buffer  (YY_BUFFER_STATE  new_buffer )
+    void yy_switch_to_buffer  (YY_BUFFER_STATE  new_buffer , yyscan_t yyscanner)
 {
-    
+    struct yyguts_t * yyg = (struct yyguts_t*)yyscanner;
+
 	/* TODO. We should be able to replace this entire function body
 	 * with
 	 *		yypop_buffer_state();
 	 *		yypush_buffer_state(new_buffer);
      */
-	yyensure_buffer_stack ();
+	yyensure_buffer_stack (yyscanner);
 	if ( YY_CURRENT_BUFFER == new_buffer )
 		return;
 
 	if ( YY_CURRENT_BUFFER )
 		{
 		/* Flush out information for old buffer. */
-		*(yy_c_buf_p) = (yy_hold_char);
-		YY_CURRENT_BUFFER_LVALUE->yy_buf_pos = (yy_c_buf_p);
-		YY_CURRENT_BUFFER_LVALUE->yy_n_chars = (yy_n_chars);
+		*yyg->yy_c_buf_p = yyg->yy_hold_char;
+		YY_CURRENT_BUFFER_LVALUE->yy_buf_pos = yyg->yy_c_buf_p;
+		YY_CURRENT_BUFFER_LVALUE->yy_n_chars = yyg->yy_n_chars;
 		}
 
 	YY_CURRENT_BUFFER_LVALUE = new_buffer;
-	yy_load_buffer_state( );
+	yy_load_buffer_state(yyscanner );
 
 	/* We don't actually know whether we did this switch during
 	 * EOF (yywrap()) processing, but the only time this flag
 	 * is looked at is after yywrap() is called, so it's safe
 	 * to go ahead and always set it.
 	 */
-	(yy_did_buffer_switch_on_eof) = 1;
+	yyg->yy_did_buffer_switch_on_eof = 1;
 }
 
-static void yy_load_buffer_state  (void)
+static void yy_load_buffer_state  (yyscan_t yyscanner)
 {
-    	(yy_n_chars) = YY_CURRENT_BUFFER_LVALUE->yy_n_chars;
-	(yytext_ptr) = (yy_c_buf_p) = YY_CURRENT_BUFFER_LVALUE->yy_buf_pos;
+    struct yyguts_t * yyg = (struct yyguts_t*)yyscanner;
+	yyg->yy_n_chars = YY_CURRENT_BUFFER_LVALUE->yy_n_chars;
+	yyg->yytext_ptr = yyg->yy_c_buf_p = YY_CURRENT_BUFFER_LVALUE->yy_buf_pos;
 	yyin = YY_CURRENT_BUFFER_LVALUE->yy_input_file;
-	(yy_hold_char) = *(yy_c_buf_p);
+	yyg->yy_hold_char = *yyg->yy_c_buf_p;
 }
 
 /** Allocate and initialize an input buffer state.
  * @param file A readable stream.
  * @param size The character buffer size in bytes. When in doubt, use @c YY_BUF_SIZE.
- * 
+ * @param yyscanner The scanner object.
  * @return the allocated buffer state.
  */
-    YY_BUFFER_STATE yy_create_buffer  (FILE * file, int  size )
+    YY_BUFFER_STATE yy_create_buffer  (FILE * file, int  size , yyscan_t yyscanner)
 {
 	YY_BUFFER_STATE b;
     
-	b = (YY_BUFFER_STATE) yyalloc(sizeof( struct yy_buffer_state )  );
+	b = (YY_BUFFER_STATE) yyalloc(sizeof( struct yy_buffer_state ) ,yyscanner );
 	if ( ! b )
 		YY_FATAL_ERROR( "out of dynamic memory in yy_create_buffer()" );
 
@@ -1312,24 +1335,25 @@ static void yy_load_buffer_state  (void)
 	/* yy_ch_buf has to be 2 characters longer than the size given because
 	 * we need to put in 2 end-of-buffer characters.
 	 */
-	b->yy_ch_buf = (char *) yyalloc(b->yy_buf_size + 2  );
+	b->yy_ch_buf = (char *) yyalloc(b->yy_buf_size + 2 ,yyscanner );
 	if ( ! b->yy_ch_buf )
 		YY_FATAL_ERROR( "out of dynamic memory in yy_create_buffer()" );
 
 	b->yy_is_our_buffer = 1;
 
-	yy_init_buffer(b,file );
+	yy_init_buffer(b,file ,yyscanner);
 
 	return b;
 }
 
 /** Destroy the buffer.
  * @param b a buffer created with yy_create_buffer()
- * 
+ * @param yyscanner The scanner object.
  */
-    void yy_delete_buffer (YY_BUFFER_STATE  b )
+    void yy_delete_buffer (YY_BUFFER_STATE  b , yyscan_t yyscanner)
 {
-    
+    struct yyguts_t * yyg = (struct yyguts_t*)yyscanner;
+
 	if ( ! b )
 		return;
 
@@ -1337,9 +1361,9 @@ static void yy_load_buffer_state  (void)
 		YY_CURRENT_BUFFER_LVALUE = (YY_BUFFER_STATE) 0;
 
 	if ( b->yy_is_our_buffer )
-		yyfree((void *) b->yy_ch_buf  );
+		yyfree((void *) b->yy_ch_buf ,yyscanner );
 
-	yyfree((void *) b  );
+	yyfree((void *) b ,yyscanner );
 }
 
 #ifndef __cplusplus
@@ -1350,12 +1374,13 @@ extern int isatty (int );
  * This function is sometimes called more than once on the same buffer,
  * such as during a yyrestart() or at EOF.
  */
-    static void yy_init_buffer  (YY_BUFFER_STATE  b, FILE * file )
+    static void yy_init_buffer  (YY_BUFFER_STATE  b, FILE * file , yyscan_t yyscanner)
 
 {
 	int oerrno = errno;
-    
-	yy_flush_buffer(b );
+    struct yyguts_t * yyg = (struct yyguts_t*)yyscanner;
+
+	yy_flush_buffer(b ,yyscanner);
 
 	b->yy_input_file = file;
 	b->yy_fill_buffer = 1;
@@ -1376,11 +1401,12 @@ extern int isatty (int );
 
 /** Discard all buffered characters. On the next scan, YY_INPUT will be called.
  * @param b the buffer state to be flushed, usually @c YY_CURRENT_BUFFER.
- * 
+ * @param yyscanner The scanner object.
  */
-    void yy_flush_buffer (YY_BUFFER_STATE  b )
+    void yy_flush_buffer (YY_BUFFER_STATE  b , yyscan_t yyscanner)
 {
-    	if ( ! b )
+    struct yyguts_t * yyg = (struct yyguts_t*)yyscanner;
+	if ( ! b )
 		return;
 
 	b->yy_n_chars = 0;
@@ -1398,114 +1424,117 @@ extern int isatty (int );
 	b->yy_buffer_status = YY_BUFFER_NEW;
 
 	if ( b == YY_CURRENT_BUFFER )
-		yy_load_buffer_state( );
+		yy_load_buffer_state(yyscanner );
 }
 
 /** Pushes the new state onto the stack. The new state becomes
  *  the current state. This function will allocate the stack
  *  if necessary.
  *  @param new_buffer The new state.
- *  
+ *  @param yyscanner The scanner object.
  */
-void yypush_buffer_state (YY_BUFFER_STATE new_buffer )
+void yypush_buffer_state (YY_BUFFER_STATE new_buffer , yyscan_t yyscanner)
 {
-    	if (new_buffer == NULL)
+    struct yyguts_t * yyg = (struct yyguts_t*)yyscanner;
+	if (new_buffer == NULL)
 		return;
 
-	yyensure_buffer_stack();
+	yyensure_buffer_stack(yyscanner);
 
 	/* This block is copied from yy_switch_to_buffer. */
 	if ( YY_CURRENT_BUFFER )
 		{
 		/* Flush out information for old buffer. */
-		*(yy_c_buf_p) = (yy_hold_char);
-		YY_CURRENT_BUFFER_LVALUE->yy_buf_pos = (yy_c_buf_p);
-		YY_CURRENT_BUFFER_LVALUE->yy_n_chars = (yy_n_chars);
+		*yyg->yy_c_buf_p = yyg->yy_hold_char;
+		YY_CURRENT_BUFFER_LVALUE->yy_buf_pos = yyg->yy_c_buf_p;
+		YY_CURRENT_BUFFER_LVALUE->yy_n_chars = yyg->yy_n_chars;
 		}
 
 	/* Only push if top exists. Otherwise, replace top. */
 	if (YY_CURRENT_BUFFER)
-		(yy_buffer_stack_top)++;
+		yyg->yy_buffer_stack_top++;
 	YY_CURRENT_BUFFER_LVALUE = new_buffer;
 
 	/* copied from yy_switch_to_buffer. */
-	yy_load_buffer_state( );
-	(yy_did_buffer_switch_on_eof) = 1;
+	yy_load_buffer_state(yyscanner );
+	yyg->yy_did_buffer_switch_on_eof = 1;
 }
 
 /** Removes and deletes the top of the stack, if present.
  *  The next element becomes the new top.
- *  
+ *  @param yyscanner The scanner object.
  */
-void yypop_buffer_state (void)
+void yypop_buffer_state (yyscan_t yyscanner)
 {
-    	if (!YY_CURRENT_BUFFER)
+    struct yyguts_t * yyg = (struct yyguts_t*)yyscanner;
+	if (!YY_CURRENT_BUFFER)
 		return;
 
-	yy_delete_buffer(YY_CURRENT_BUFFER );
+	yy_delete_buffer(YY_CURRENT_BUFFER ,yyscanner);
 	YY_CURRENT_BUFFER_LVALUE = NULL;
-	if ((yy_buffer_stack_top) > 0)
-		--(yy_buffer_stack_top);
+	if (yyg->yy_buffer_stack_top > 0)
+		--yyg->yy_buffer_stack_top;
 
 	if (YY_CURRENT_BUFFER) {
-		yy_load_buffer_state( );
-		(yy_did_buffer_switch_on_eof) = 1;
+		yy_load_buffer_state(yyscanner );
+		yyg->yy_did_buffer_switch_on_eof = 1;
 	}
 }
 
 /* Allocates the stack if it does not exist.
  *  Guarantees space for at least one push.
  */
-static void yyensure_buffer_stack (void)
+static void yyensure_buffer_stack (yyscan_t yyscanner)
 {
 	int num_to_alloc;
-    
-	if (!(yy_buffer_stack)) {
+    struct yyguts_t * yyg = (struct yyguts_t*)yyscanner;
+
+	if (!yyg->yy_buffer_stack) {
 
 		/* First allocation is just for 2 elements, since we don't know if this
 		 * scanner will even need a stack. We use 2 instead of 1 to avoid an
 		 * immediate realloc on the next call.
          */
 		num_to_alloc = 1;
-		(yy_buffer_stack) = (struct yy_buffer_state**)yyalloc
+		yyg->yy_buffer_stack = (struct yy_buffer_state**)yyalloc
 								(num_to_alloc * sizeof(struct yy_buffer_state*)
-								);
-		if ( ! (yy_buffer_stack) )
+								, yyscanner);
+		if ( ! yyg->yy_buffer_stack )
 			YY_FATAL_ERROR( "out of dynamic memory in yyensure_buffer_stack()" );
 								  
-		memset((yy_buffer_stack), 0, num_to_alloc * sizeof(struct yy_buffer_state*));
+		memset(yyg->yy_buffer_stack, 0, num_to_alloc * sizeof(struct yy_buffer_state*));
 				
-		(yy_buffer_stack_max) = num_to_alloc;
-		(yy_buffer_stack_top) = 0;
+		yyg->yy_buffer_stack_max = num_to_alloc;
+		yyg->yy_buffer_stack_top = 0;
 		return;
 	}
 
-	if ((yy_buffer_stack_top) >= ((yy_buffer_stack_max)) - 1){
+	if (yyg->yy_buffer_stack_top >= (yyg->yy_buffer_stack_max) - 1){
 
 		/* Increase the buffer to prepare for a possible push. */
 		int grow_size = 8 /* arbitrary grow size */;
 
-		num_to_alloc = (yy_buffer_stack_max) + grow_size;
-		(yy_buffer_stack) = (struct yy_buffer_state**)yyrealloc
-								((yy_buffer_stack),
+		num_to_alloc = yyg->yy_buffer_stack_max + grow_size;
+		yyg->yy_buffer_stack = (struct yy_buffer_state**)yyrealloc
+								(yyg->yy_buffer_stack,
 								num_to_alloc * sizeof(struct yy_buffer_state*)
-								);
-		if ( ! (yy_buffer_stack) )
+								, yyscanner);
+		if ( ! yyg->yy_buffer_stack )
 			YY_FATAL_ERROR( "out of dynamic memory in yyensure_buffer_stack()" );
 
 		/* zero only the new slots.*/
-		memset((yy_buffer_stack) + (yy_buffer_stack_max), 0, grow_size * sizeof(struct yy_buffer_state*));
-		(yy_buffer_stack_max) = num_to_alloc;
+		memset(yyg->yy_buffer_stack + yyg->yy_buffer_stack_max, 0, grow_size * sizeof(struct yy_buffer_state*));
+		yyg->yy_buffer_stack_max = num_to_alloc;
 	}
 }
 
 /** Setup the input buffer state to scan directly from a user-specified character buffer.
  * @param base the character buffer
  * @param size the size in bytes of the character buffer
- * 
+ * @param yyscanner The scanner object.
  * @return the newly allocated buffer state object. 
  */
-YY_BUFFER_STATE yy_scan_buffer  (char * base, yy_size_t  size )
+YY_BUFFER_STATE yy_scan_buffer  (char * base, yy_size_t  size , yyscan_t yyscanner)
 {
 	YY_BUFFER_STATE b;
     
@@ -1515,7 +1544,7 @@ YY_BUFFER_STATE yy_scan_buffer  (char * base, yy_size_t  size )
 		/* They forgot to leave room for the EOB's. */
 		return 0;
 
-	b = (YY_BUFFER_STATE) yyalloc(sizeof( struct yy_buffer_state )  );
+	b = (YY_BUFFER_STATE) yyalloc(sizeof( struct yy_buffer_state ) ,yyscanner );
 	if ( ! b )
 		YY_FATAL_ERROR( "out of dynamic memory in yy_scan_buffer()" );
 
@@ -1529,7 +1558,7 @@ YY_BUFFER_STATE yy_scan_buffer  (char * base, yy_size_t  size )
 	b->yy_fill_buffer = 0;
 	b->yy_buffer_status = YY_BUFFER_NEW;
 
-	yy_switch_to_buffer(b  );
+	yy_switch_to_buffer(b ,yyscanner );
 
 	return b;
 }
@@ -1537,25 +1566,25 @@ YY_BUFFER_STATE yy_scan_buffer  (char * base, yy_size_t  size )
 /** Setup the input buffer state to scan a string. The next call to yylex() will
  * scan from a @e copy of @a str.
  * @param yystr a NUL-terminated string to scan
- * 
+ * @param yyscanner The scanner object.
  * @return the newly allocated buffer state object.
  * @note If you want to scan bytes that may contain NUL values, then use
  *       yy_scan_bytes() instead.
  */
-YY_BUFFER_STATE yy_scan_string (yyconst char * yystr )
+YY_BUFFER_STATE yy_scan_string (yyconst char * yystr , yyscan_t yyscanner)
 {
     
-	return yy_scan_bytes(yystr,strlen(yystr) );
+	return yy_scan_bytes(yystr,strlen(yystr) ,yyscanner);
 }
 
 /** Setup the input buffer state to scan the given bytes. The next call to yylex() will
  * scan from a @e copy of @a bytes.
  * @param yybytes the byte buffer to scan
  * @param _yybytes_len the number of bytes in the buffer pointed to by @a bytes.
- * 
+ * @param yyscanner The scanner object.
  * @return the newly allocated buffer state object.
  */
-YY_BUFFER_STATE yy_scan_bytes  (yyconst char * yybytes, int  _yybytes_len )
+YY_BUFFER_STATE yy_scan_bytes  (yyconst char * yybytes, int  _yybytes_len , yyscan_t yyscanner)
 {
 	YY_BUFFER_STATE b;
 	char *buf;
@@ -1564,7 +1593,7 @@ YY_BUFFER_STATE yy_scan_bytes  (yyconst char * yybytes, int  _yybytes_len )
     
 	/* Get memory for full buffer, including space for trailing EOB's. */
 	n = _yybytes_len + 2;
-	buf = (char *) yyalloc(n  );
+	buf = (char *) yyalloc(n ,yyscanner );
 	if ( ! buf )
 		YY_FATAL_ERROR( "out of dynamic memory in yy_scan_bytes()" );
 
@@ -1573,7 +1602,7 @@ YY_BUFFER_STATE yy_scan_bytes  (yyconst char * yybytes, int  _yybytes_len )
 
 	buf[_yybytes_len] = buf[_yybytes_len+1] = YY_END_OF_BUFFER_CHAR;
 
-	b = yy_scan_buffer(buf,n );
+	b = yy_scan_buffer(buf,n ,yyscanner);
 	if ( ! b )
 		YY_FATAL_ERROR( "bad buffer in yy_scan_bytes()" );
 
@@ -1589,7 +1618,7 @@ YY_BUFFER_STATE yy_scan_bytes  (yyconst char * yybytes, int  _yybytes_len )
 #define YY_EXIT_FAILURE 2
 #endif
 
-static void yy_fatal_error (yyconst char* msg )
+static void yy_fatal_error (yyconst char* msg , yyscan_t yyscanner)
 {
     	(void) fprintf( stderr, "%s\n", msg );
 	exit( YY_EXIT_FAILURE );
@@ -1604,106 +1633,241 @@ static void yy_fatal_error (yyconst char* msg )
 		/* Undo effects of setting up yytext. */ \
         int yyless_macro_arg = (n); \
         YY_LESS_LINENO(yyless_macro_arg);\
-		yytext[yyleng] = (yy_hold_char); \
-		(yy_c_buf_p) = yytext + yyless_macro_arg; \
-		(yy_hold_char) = *(yy_c_buf_p); \
-		*(yy_c_buf_p) = '\0'; \
+		yytext[yyleng] = yyg->yy_hold_char; \
+		yyg->yy_c_buf_p = yytext + yyless_macro_arg; \
+		yyg->yy_hold_char = *yyg->yy_c_buf_p; \
+		*yyg->yy_c_buf_p = '\0'; \
 		yyleng = yyless_macro_arg; \
 		} \
 	while ( 0 )
 
 /* Accessor  methods (get/set functions) to struct members. */
 
-/** Get the current line number.
- * 
+/** Get the user-defined data for this scanner.
+ * @param yyscanner The scanner object.
  */
-int yyget_lineno  (void)
+YY_EXTRA_TYPE yyget_extra  (yyscan_t yyscanner)
 {
-        
+    struct yyguts_t * yyg = (struct yyguts_t*)yyscanner;
+    return yyextra;
+}
+
+/** Get the current line number.
+ * @param yyscanner The scanner object.
+ */
+int yyget_lineno  (yyscan_t yyscanner)
+{
+    struct yyguts_t * yyg = (struct yyguts_t*)yyscanner;
+    
+        if (! YY_CURRENT_BUFFER)
+            return 0;
+    
     return yylineno;
 }
 
-/** Get the input stream.
- * 
+/** Get the current column number.
+ * @param yyscanner The scanner object.
  */
-FILE *yyget_in  (void)
+int yyget_column  (yyscan_t yyscanner)
 {
-        return yyin;
+    struct yyguts_t * yyg = (struct yyguts_t*)yyscanner;
+    
+        if (! YY_CURRENT_BUFFER)
+            return 0;
+    
+    return yycolumn;
+}
+
+/** Get the input stream.
+ * @param yyscanner The scanner object.
+ */
+FILE *yyget_in  (yyscan_t yyscanner)
+{
+    struct yyguts_t * yyg = (struct yyguts_t*)yyscanner;
+    return yyin;
 }
 
 /** Get the output stream.
- * 
+ * @param yyscanner The scanner object.
  */
-FILE *yyget_out  (void)
+FILE *yyget_out  (yyscan_t yyscanner)
 {
-        return yyout;
+    struct yyguts_t * yyg = (struct yyguts_t*)yyscanner;
+    return yyout;
 }
 
 /** Get the length of the current token.
- * 
+ * @param yyscanner The scanner object.
  */
-int yyget_leng  (void)
+int yyget_leng  (yyscan_t yyscanner)
 {
-        return yyleng;
+    struct yyguts_t * yyg = (struct yyguts_t*)yyscanner;
+    return yyleng;
 }
 
 /** Get the current token.
- * 
+ * @param yyscanner The scanner object.
  */
 
-char *yyget_text  (void)
+char *yyget_text  (yyscan_t yyscanner)
 {
-        return yytext;
+    struct yyguts_t * yyg = (struct yyguts_t*)yyscanner;
+    return yytext;
+}
+
+/** Set the user-defined data. This data is never touched by the scanner.
+ * @param user_defined The data to be associated with this scanner.
+ * @param yyscanner The scanner object.
+ */
+void yyset_extra (YY_EXTRA_TYPE  user_defined , yyscan_t yyscanner)
+{
+    struct yyguts_t * yyg = (struct yyguts_t*)yyscanner;
+    yyextra = user_defined ;
 }
 
 /** Set the current line number.
  * @param line_number
- * 
+ * @param yyscanner The scanner object.
  */
-void yyset_lineno (int  line_number )
+void yyset_lineno (int  line_number , yyscan_t yyscanner)
 {
+    struct yyguts_t * yyg = (struct yyguts_t*)yyscanner;
+
+        /* lineno is only valid if an input buffer exists. */
+        if (! YY_CURRENT_BUFFER )
+           yy_fatal_error( "yyset_lineno called with no buffer" , yyscanner); 
     
     yylineno = line_number;
 }
 
+/** Set the current column.
+ * @param line_number
+ * @param yyscanner The scanner object.
+ */
+void yyset_column (int  column_no , yyscan_t yyscanner)
+{
+    struct yyguts_t * yyg = (struct yyguts_t*)yyscanner;
+
+        /* column is only valid if an input buffer exists. */
+        if (! YY_CURRENT_BUFFER )
+           yy_fatal_error( "yyset_column called with no buffer" , yyscanner); 
+    
+    yycolumn = column_no;
+}
+
 /** Set the input stream. This does not discard the current
  * input buffer.
  * @param in_str A readable stream.
- * 
+ * @param yyscanner The scanner object.
  * @see yy_switch_to_buffer
  */
-void yyset_in (FILE *  in_str )
+void yyset_in (FILE *  in_str , yyscan_t yyscanner)
 {
-        yyin = in_str ;
+    struct yyguts_t * yyg = (struct yyguts_t*)yyscanner;
+    yyin = in_str ;
 }
 
-void yyset_out (FILE *  out_str )
+void yyset_out (FILE *  out_str , yyscan_t yyscanner)
 {
-        yyout = out_str ;
+    struct yyguts_t * yyg = (struct yyguts_t*)yyscanner;
+    yyout = out_str ;
 }
 
-int yyget_debug  (void)
+int yyget_debug  (yyscan_t yyscanner)
 {
-        return yy_flex_debug;
+    struct yyguts_t * yyg = (struct yyguts_t*)yyscanner;
+    return yy_flex_debug;
 }
 
-void yyset_debug (int  bdebug )
+void yyset_debug (int  bdebug , yyscan_t yyscanner)
 {
-        yy_flex_debug = bdebug ;
+    struct yyguts_t * yyg = (struct yyguts_t*)yyscanner;
+    yy_flex_debug = bdebug ;
 }
 
-static int yy_init_globals (void)
+/* Accessor methods for yylval and yylloc */
+
+/* User-visible API */
+
+/* yylex_init is special because it creates the scanner itself, so it is
+ * the ONLY reentrant function that doesn't take the scanner as the last argument.
+ * That's why we explicitly handle the declaration, instead of using our macros.
+ */
+
+int yylex_init(yyscan_t* ptr_yy_globals)
+
 {
-        /* Initialization is the same as for the non-reentrant scanner.
+    if (ptr_yy_globals == NULL){
+        errno = EINVAL;
+        return 1;
+    }
+
+    *ptr_yy_globals = (yyscan_t) yyalloc ( sizeof( struct yyguts_t ), NULL );
+
+    if (*ptr_yy_globals == NULL){
+        errno = ENOMEM;
+        return 1;
+    }
+
+    /* By setting to 0xAA, we expose bugs in yy_init_globals. Leave at 0x00 for releases. */
+    memset(*ptr_yy_globals,0x00,sizeof(struct yyguts_t));
+
+    return yy_init_globals ( *ptr_yy_globals );
+}
+
+/* yylex_init_extra has the same functionality as yylex_init, but follows the
+ * convention of taking the scanner as the last argument. Note however, that
+ * this is a *pointer* to a scanner, as it will be allocated by this call (and
+ * is the reason, too, why this function also must handle its own declaration).
+ * The user defined value in the first argument will be available to yyalloc in
+ * the yyextra field.
+ */
+
+int yylex_init_extra(YY_EXTRA_TYPE yy_user_defined,yyscan_t* ptr_yy_globals )
+
+{
+    struct yyguts_t dummy_yyguts;
+
+    yyset_extra (yy_user_defined, &dummy_yyguts);
+
+    if (ptr_yy_globals == NULL){
+        errno = EINVAL;
+        return 1;
+    }
+	
+    *ptr_yy_globals = (yyscan_t) yyalloc ( sizeof( struct yyguts_t ), &dummy_yyguts );
+	
+    if (*ptr_yy_globals == NULL){
+        errno = ENOMEM;
+        return 1;
+    }
+    
+    /* By setting to 0xAA, we expose bugs in
+    yy_init_globals. Leave at 0x00 for releases. */
+    memset(*ptr_yy_globals,0x00,sizeof(struct yyguts_t));
+    
+    yyset_extra (yy_user_defined, *ptr_yy_globals);
+    
+    return yy_init_globals ( *ptr_yy_globals );
+}
+
+static int yy_init_globals (yyscan_t yyscanner)
+{
+    struct yyguts_t * yyg = (struct yyguts_t*)yyscanner;
+    /* Initialization is the same as for the non-reentrant scanner.
      * This function is called from yylex_destroy(), so don't allocate here.
      */
 
-    (yy_buffer_stack) = 0;
-    (yy_buffer_stack_top) = 0;
-    (yy_buffer_stack_max) = 0;
-    (yy_c_buf_p) = (char *) 0;
-    (yy_init) = 0;
-    (yy_start) = 0;
+    yyg->yy_buffer_stack = 0;
+    yyg->yy_buffer_stack_top = 0;
+    yyg->yy_buffer_stack_max = 0;
+    yyg->yy_c_buf_p = (char *) 0;
+    yyg->yy_init = 0;
+    yyg->yy_start = 0;
+
+    yyg->yy_start_stack_ptr = 0;
+    yyg->yy_start_stack_depth = 0;
+    yyg->yy_start_stack =  NULL;
 
 /* Defined in main.c */
 #ifdef YY_STDINIT
@@ -1721,24 +1885,32 @@ static int yy_init_globals (void)
 }
 
 /* yylex_destroy is for both reentrant and non-reentrant scanners. */
-int yylex_destroy  (void)
+int yylex_destroy  (yyscan_t yyscanner)
 {
-    
+    struct yyguts_t * yyg = (struct yyguts_t*)yyscanner;
+
     /* Pop the buffer stack, destroying each element. */
 	while(YY_CURRENT_BUFFER){
-		yy_delete_buffer(YY_CURRENT_BUFFER  );
+		yy_delete_buffer(YY_CURRENT_BUFFER ,yyscanner );
 		YY_CURRENT_BUFFER_LVALUE = NULL;
-		yypop_buffer_state();
+		yypop_buffer_state(yyscanner);
 	}
 
 	/* Destroy the stack itself. */
-	yyfree((yy_buffer_stack) );
-	(yy_buffer_stack) = NULL;
+	yyfree(yyg->yy_buffer_stack ,yyscanner);
+	yyg->yy_buffer_stack = NULL;
+
+    /* Destroy the start condition stack. */
+        yyfree(yyg->yy_start_stack ,yyscanner );
+        yyg->yy_start_stack = NULL;
 
     /* Reset the globals. This is important in a non-reentrant scanner so the next time
      * yylex() is called, initialization will occur. */
-    yy_init_globals( );
+    yy_init_globals( yyscanner);
 
+    /* Destroy the main struct (reentrant only). */
+    yyfree ( yyscanner , yyscanner );
+    yyscanner = NULL;
     return 0;
 }
 
@@ -1747,7 +1919,7 @@ int yylex_destroy  (void)
  */
 
 #ifndef yytext_ptr
-static void yy_flex_strncpy (char* s1, yyconst char * s2, int n )
+static void yy_flex_strncpy (char* s1, yyconst char * s2, int n , yyscan_t yyscanner)
 {
 	register int i;
 	for ( i = 0; i < n; ++i )
@@ -1756,7 +1928,7 @@ static void yy_flex_strncpy (char* s1, yyconst char * s2, int n )
 #endif
 
 #ifdef YY_NEED_STRLEN
-static int yy_flex_strlen (yyconst char * s )
+static int yy_flex_strlen (yyconst char * s , yyscan_t yyscanner)
 {
 	register int n;
 	for ( n = 0; s[n]; ++n )
@@ -1766,12 +1938,12 @@ static int yy_flex_strlen (yyconst char * s )
 }
 #endif
 
-void *yyalloc (yy_size_t  size )
+void *yyalloc (yy_size_t  size , yyscan_t yyscanner)
 {
 	return (void *) malloc( size );
 }
 
-void *yyrealloc  (void * ptr, yy_size_t  size )
+void *yyrealloc  (void * ptr, yy_size_t  size , yyscan_t yyscanner)
 {
 	/* The cast to (char *) in the following accommodates both
 	 * implementations that use char* generic pointers, and those
@@ -1783,11 +1955,11 @@ void *yyrealloc  (void * ptr, yy_size_t  size )
 	return (void *) realloc( (char *) ptr, size );
 }
 
-void yyfree (void * ptr )
+void yyfree (void * ptr , yyscan_t yyscanner)
 {
 	free( (char *) ptr );	/* see yyrealloc() for (char *) cast */
 }
 
 #define YYTABLES_NAME "yytables"
 
-#line 55 "shell_lex.l"
+#line 53 "shell_lex.l"
diff --git a/shell_lex.l b/shell_lex.l
index 240b1ef..65f8987 100644
--- a/shell_lex.l
+++ b/shell_lex.l
@@ -17,12 +17,10 @@
  */
 
 %{
-#include "shell.h"
+#include "shell_internal.h"
 #include <string.h>
 #include <stdlib.h>
 
-#define YY_INPUT(buf, result, max_size) result = shell_pull(buf, max_size);
-
 static char *str_append(char *str, const char *src) {
 	if(str) {
 		size_t newlen = strlen(str) + strlen(src) + 1;
@@ -39,16 +37,16 @@ static char *str_append(char *str, const char *src) {
 		return strdup(src);
 }
 %}
-%option noyywrap nounput noinput batch
+%option noyywrap nounput noinput batch reentrant
 
 %x STR
 %%
-["]		{ strval = NULL; BEGIN(STR); }
+["]		{ yyextra->strval = NULL; BEGIN(STR); }
 ;		return TOK_SEPARATOR;
 [[:space:]]+	return TOK_SPACE;
 [#]	return TOK_COMMENT;
-[^[:space:];"#]+	{ strval = strdup(yytext); return TOK_STRING; }
-<STR>[^\\"]+	strval = str_append(strval, yytext);
-<STR>\\["]	strval = str_append(strval, "\"");
-<STR>\\		strval = str_append(strval, "\\");
+[^[:space:];"#]+	{ yyextra->strval = strdup(yytext); return TOK_STRING; }
+<STR>[^\\"]+	yyextra->strval = str_append(yyextra->strval, yytext);
+<STR>\\["]	yyextra->strval = str_append(yyextra->strval, "\"");
+<STR>\\		yyextra->strval = str_append(yyextra->strval, "\\");
 <STR>["]	{ BEGIN(INITIAL); return TOK_STRING; }
diff --git a/spl_cmdset.c b/spl_cmdset.c
index 86503e5..f226efa 100644
--- a/spl_cmdset.c
+++ b/spl_cmdset.c
@@ -26,9 +26,9 @@
 #include "config.h"
 #include "ingenic.h"
 
-static int spl_memtest(int argc, char *argv[]);
-static int spl_gpio(int argc, char *argv[]);
-static int spl_boot(int argc, char *argv[]);
+static int spl_memtest(shell_context_t *ctx, int argc, char *argv[]);
+static int spl_gpio(shell_context_t *ctx, int argc, char *argv[]);
+static int spl_boot(shell_context_t *ctx, int argc, char *argv[]);
 
 const shell_command_t spl_cmdset[] = {
 	{ "memtest", "[BASE <SIZE>] - SDRAM test", spl_memtest },
@@ -37,14 +37,14 @@ const shell_command_t spl_cmdset[] = {
 	{ NULL, NULL, NULL }
 };
 
-static int spl_stage1_op(uint32_t op, uint32_t pin, uint32_t base, uint32_t size) {
+static int spl_stage1_op(shell_context_t *ctx, uint32_t op, uint32_t pin, uint32_t base, uint32_t size) {
 	if(cfg_getenv("STAGE1_FILE") == NULL) {
 		printf("Variable STAGE1_FILE is not set\n");
 
 		return -1;
 	}
 
-	int ret = ingenic_stage1_debugop(shell_device(), cfg_getenv("STAGE1_FILE"), op, pin, base, size);
+	int ret = ingenic_stage1_debugop(shell_device(ctx), cfg_getenv("STAGE1_FILE"), op, pin, base, size);
 
 	if(ret == -1)
 		perror("ingenic_stage1_debugop");
@@ -52,7 +52,7 @@ static int spl_stage1_op(uint32_t op, uint32_t pin, uint32_t base, uint32_t size
 	return ret;
 }
 
-static int spl_memtest(int argc, char *argv[]) {
+static int spl_memtest(shell_context_t *ctx, int argc, char *argv[]) {
 	if(argc != 1 && argc != 3) {
 		printf("Usage: %s [BASE <SIZE>]\n", argv[0]);
 
@@ -66,7 +66,7 @@ static int spl_memtest(int argc, char *argv[]) {
 		size = strtoul(argv[2], NULL, 0);
 	} else {
 		start = SDRAM_BASE;
-		size = ingenic_sdram_size(shell_device());
+		size = ingenic_sdram_size(shell_device(ctx));
 	}
 
 	if(cfg_getenv("STAGE1_FILE") == NULL) {
@@ -77,7 +77,7 @@ static int spl_memtest(int argc, char *argv[]) {
 
 	uint32_t fail;
 
-	int ret = ingenic_memtest(shell_device(), cfg_getenv("STAGE1_FILE"), start, size, &fail);
+	int ret = ingenic_memtest(shell_device(ctx), cfg_getenv("STAGE1_FILE"), start, size, &fail);
 
 	if(ret == -1) {
 		if(errno == EFAULT) {
@@ -93,7 +93,7 @@ static int spl_memtest(int argc, char *argv[]) {
 	return ret;
 }
 
-static int spl_gpio(int argc, char *argv[]) {
+static int spl_gpio(shell_context_t *ctx, int argc, char *argv[]) {
 	if(argc != 3 || (strcmp(argv[2], "0") && strcmp(argv[2], "1"))) {
 		printf("Usage: %s <PIN> <STATE>\n", argv[0]);
 		printf("  STATE := 0 | 1\n");
@@ -101,15 +101,15 @@ static int spl_gpio(int argc, char *argv[]) {
 		return -1;
 	}
 
-	return spl_stage1_op(!strcmp(argv[2], "1") ? STAGE1_DEBUG_GPIO_SET : STAGE1_DEBUG_GPIO_CLEAR, atoi(argv[1]), 0, 0);
+	return spl_stage1_op(ctx, !strcmp(argv[2], "1") ? STAGE1_DEBUG_GPIO_SET : STAGE1_DEBUG_GPIO_CLEAR, atoi(argv[1]), 0, 0);
 }
 
-static int spl_boot(int argc, char *argv[]) {
+static int spl_boot(shell_context_t *ctx, int argc, char *argv[]) {
 	if(argc != 1) {
 		printf("Usage: %s\n", argv[0]);
 	}
 
-	int ret = spl_stage1_op(STAGE1_DEBUG_BOOT, 0, 0, 0);
+	int ret = spl_stage1_op(ctx, STAGE1_DEBUG_BOOT, 0, 0, 0);
 
 	if(ret == -1)
 		return -1;
@@ -120,7 +120,7 @@ static int spl_boot(int argc, char *argv[]) {
 		return -1;
 	}
 
-	ret = ingenic_loadstage(shell_device(), INGENIC_STAGE2, cfg_getenv("STAGE2_FILE"));
+	ret = ingenic_loadstage(shell_device(ctx), INGENIC_STAGE2, cfg_getenv("STAGE2_FILE"));
 
 	if(ret == -1) {
 		perror("ingenic_loadstage");
@@ -128,7 +128,7 @@ static int spl_boot(int argc, char *argv[]) {
 		return -1;
 	}
 
-	ret = ingenic_configure_stage2(shell_device());
+	ret = ingenic_configure_stage2(shell_device(ctx));
 
 	if(ret == -1)
 		perror("ingenic_configure_stage2");
diff --git a/usbboot_cmdset.c b/usbboot_cmdset.c
index e177246..dd723bb 100644
--- a/usbboot_cmdset.c
+++ b/usbboot_cmdset.c
@@ -25,14 +25,14 @@
 #include "ingenic.h"
 #include "config.h"
 
-static int usbboot_boot(int argc, char *argv[]);
-static int usbboot_load(int argc, char *argv[]);
-static int usbboot_go(int argc, char *argv[]);
-static int usbboot_nquery(int argc, char *argv[]);
-static int usbboot_ndump(int argc, char *argv[]);
-static int usbboot_nerase(int argc, char *argv[]);
-static int usbboot_nprogram(int argc, char *argv[]);
-static int usbboot_nload(int argc, char *argv[]);
+static int usbboot_boot(shell_context_t *ctx, int argc, char *argv[]);
+static int usbboot_load(shell_context_t *ctx, int argc, char *argv[]);
+static int usbboot_go(shell_context_t *ctx, int argc, char *argv[]);
+static int usbboot_nquery(shell_context_t *ctx, int argc, char *argv[]);
+static int usbboot_ndump(shell_context_t *ctx, int argc, char *argv[]);
+static int usbboot_nerase(shell_context_t *ctx, int argc, char *argv[]);
+static int usbboot_nprogram(shell_context_t *ctx, int argc, char *argv[]);
+static int usbboot_nload(shell_context_t *ctx, int argc, char *argv[]);
 
 const shell_command_t usbboot_cmdset[] = {
 
@@ -51,8 +51,8 @@ const shell_command_t usbboot_cmdset[] = {
 	{ NULL, NULL, NULL }
 };
 
-static int usbboot_boot(int argc, char *argv[]) {
-	int ret = ingenic_configure_stage2(shell_device());
+static int usbboot_boot(shell_context_t *ctx, int argc, char *argv[]) {
+	int ret = ingenic_configure_stage2(shell_device(ctx));
 
 	if(ret == -1)
 		perror("ingenic_configure_stage2");
@@ -60,14 +60,14 @@ static int usbboot_boot(int argc, char *argv[]) {
 	return ret;
 }
 
-static int usbboot_load(int argc, char *argv[]) {
+static int usbboot_load(shell_context_t *ctx, int argc, char *argv[]) {
 	if(argc != 3) {
 		printf("Usage: %s <FILE> <BASE>\n", argv[0]);
 
 		return -1;
 	}
 
-	int ret = ingenic_load_sdram_file(shell_device(), strtoul(argv[2], NULL, 0), argv[1]);
+	int ret = ingenic_load_sdram_file(shell_device(ctx), strtoul(argv[2], NULL, 0), argv[1]);
 
 	if(ret == -1)
 		perror("ingenic_load_sdram_file");
@@ -75,14 +75,14 @@ static int usbboot_load(int argc, char *argv[]) {
 	return ret;
 }
 
-static int usbboot_go(int argc, char *argv[]) {
+static int usbboot_go(shell_context_t *ctx, int argc, char *argv[]) {
 	if(argc != 2) {
 		printf("Usage: %s <ADDRESS>\n", argv[0]);
 
 		return -1;
 	}
 
-	int ret = ingenic_go(shell_device(), strtoul(argv[1], NULL, 0));
+	int ret = ingenic_go(shell_device(ctx), strtoul(argv[1], NULL, 0));
 
 	if(ret == -1)
 		perror("ingenic_go");
@@ -90,7 +90,7 @@ static int usbboot_go(int argc, char *argv[]) {
 	return ret;
 }
 
-static int usbboot_nquery(int argc, char *argv[]) {
+static int usbboot_nquery(shell_context_t *ctx, int argc, char *argv[]) {
 	if(argc != 2) {
 		printf("Usage: %s <DEVICE>\n", argv[0]);
 
@@ -99,7 +99,7 @@ static int usbboot_nquery(int argc, char *argv[]) {
 
 	nand_info_t info;
 
-	int ret = ingenic_query_nand(shell_device(), atoi(argv[1]), &info);
+	int ret = ingenic_query_nand(shell_device(ctx), atoi(argv[1]), &info);
 
 	if(ret == -1) {
 		perror("ingenic_query_nand");
@@ -119,7 +119,7 @@ static int usbboot_nquery(int argc, char *argv[]) {
 	return 0;
 }
 
-static int usbboot_ndump(int argc, char *argv[]) {
+static int usbboot_ndump(shell_context_t *ctx, int argc, char *argv[]) {
 	if(argc != 5) {
 		printf("Usage: %s <DEVICE> <STARTPAGE> <PAGES> <FILE>\n", argv[0]);
 		
@@ -131,7 +131,7 @@ static int usbboot_ndump(int argc, char *argv[]) {
 	if(cfg_getenv("NAND_RAW"))
 		type |= NAND_RAW;
 	
-	int ret = ingenic_dump_nand(shell_device(), atoi(argv[1]), atoi(argv[2]), atoi(argv[3]), type, argv[4]);
+	int ret = ingenic_dump_nand(shell_device(ctx), atoi(argv[1]), atoi(argv[2]), atoi(argv[3]), type, argv[4]);
 	
 	if(ret == -1)
 		perror("ingenic_dump_nand");
@@ -139,14 +139,14 @@ static int usbboot_ndump(int argc, char *argv[]) {
 	return ret;
 }
 
-static int usbboot_nerase(int argc, char *argv[]) {
+static int usbboot_nerase(shell_context_t *ctx, int argc, char *argv[]) {
 	if(argc != 4) {
 		printf("Usage: %s <DEVICE> <STARTBLOCK> <BLOCKS>\n", argv[0]);
 		
 		return -1;
 	}
 	
-	int ret = ingenic_erase_nand(shell_device(), atoi(argv[1]), atoi(argv[2]), atoi(argv[3]));
+	int ret = ingenic_erase_nand(shell_device(ctx), atoi(argv[1]), atoi(argv[2]), atoi(argv[3]));
 	
 	if(ret == -1)
 		perror("ingenic_erase_nand");
@@ -155,7 +155,7 @@ static int usbboot_nerase(int argc, char *argv[]) {
 	
 }
 
-static int usbboot_nprogram(int argc, char *argv[]) {
+static int usbboot_nprogram(shell_context_t *ctx, int argc, char *argv[]) {
 	if(argc != 4) {
 		printf("Usage: %s <DEVICE> <STARTPAGE> <FILE>\n", argv[0]);
 		
@@ -172,7 +172,7 @@ static int usbboot_nprogram(int argc, char *argv[]) {
 	} else 
 		type = NO_OOB;
 	
-	int ret = ingenic_program_nand(shell_device(), atoi(argv[1]), atoi(argv[2]), type, argv[3]);
+	int ret = ingenic_program_nand(shell_device(ctx), atoi(argv[1]), atoi(argv[2]), type, argv[3]);
 	
 	if(ret == -1)
 		perror("ingenic_program_nand");
@@ -180,14 +180,14 @@ static int usbboot_nprogram(int argc, char *argv[]) {
 	return ret;
 }
 
-static int usbboot_nload(int argc, char *argv[]) {
+static int usbboot_nload(shell_context_t *ctx, int argc, char *argv[]) {
 	if(argc != 5) {
 		printf("Usage: %s <DEVICE> <STARTPAGE> <PAGES> <BASE>\n", argv[0]);
 		
 		return -1;
 	}
 	
-	int ret = ingenic_load_nand(shell_device(), atoi(argv[1]), atoi(argv[2]), atoi(argv[3]), strtoul(argv[4], NULL, 0));
+	int ret = ingenic_load_nand(shell_device(ctx), atoi(argv[1]), atoi(argv[2]), atoi(argv[3]), strtoul(argv[4], NULL, 0));
 	
 	if(ret == -1)
 		perror("ingenic_load_nand");