b2/: finish unit handling and move most of its processing to the match side

The ${foo#unit} syntax didn't really make sense because it created
a large number of potential error conditions on the assignment side
and didn't help with finding compatible fields.

With all this moved to the match side, an invalid syntax simply causes
a mismatch.

b2/SUBST

@@ -1,14 +1,18 @@
 REF=R[0-9]* {
 	T=R
-	VAL=* { R=$$#R }
+	VAL=(#R) { R=$1 }
 	TOL = 5%
-	FN=*% { TOL=${$#%} }
+	FN=*% { TOL=$$ }
 	break REF
 //	end break again
 }
 
 /*
-pattern: () * ? .
+pattern:
+  () |  like in RE
+  * ?   like in glob
+  (#U)  expect a numeric value of unit U (use substring to get canonical value)
+
 subst:  $1 ... $field
 
 substring:
@@ -17,9 +21,15 @@ variable:
   $foo, ...
 with curly braces:
   ${foo}, ...
-unit conversion:
-  $foo#V
-  ${1#R}
 input variable:
   $$
+
+  Caveat:
+
+  Wrong: FN=* { X=$FN }		there is no variable called FN
+  Right: FN=* { X=$$ }		yields the Fn field selected by FN
+
+  Wrong: VAL=(#R) { R=$VAL }	yields literal value
+  Wrong: VAL=(#R) { R=$$ }	yields literal value
+  Right: VAL=(#R) { R=$1 }	yield canonicalized value
 */

b2/subex.c

@@ -13,8 +13,10 @@
 #include <stdlib.h>
 #include <stdio.h>
 #include <string.h>
+#include <ctype.h>
 #include <sys/types.h>
 #include <regex.h>
+#include <assert.h>
 
 #include "util.h"
 #include "vstring.h"
@@ -32,17 +34,66 @@ static const char *fn = NULL, *f[FIELDS];
 static struct subst jump_end;
 
 
-/*
+
- * TODO: decide what to do with units
+static char *canonicalize(const char *s, char unit)
- */
+{
+	char *res;
+	int res_len = 0;
+	int seen_dot = 0;
+	int seen_unit = 0;
+	char mult = 0;
+
+	if (!unit)
+		return stralloc(s);
+	res = stralloc("");
+	while (*s) {
+		if (*s == unit) {
+			assert(!seen_unit);
+			if (!s[1])
+				break;
+			if (!seen_dot)
+				append_char(&res, &res_len, '.');
+			seen_unit = seen_dot = 1;
+			s++;
+			continue;
+		}
+		if (*s == '.') {
+			assert(!seen_dot);
+			append_char(&res, &res_len, '.');
+			seen_dot = 1;
+		} else if (*s == '-' || isdigit(*s)) {
+			append_char(&res, &res_len, *s);
+			s++;
+			continue;
+		} else if (strchr(MULT_CHARS, *s)) {
+			assert(!seen_unit);
+			assert(!mult);
+			mult = *s;
+			if (!seen_dot)
+				append_char(&res, &res_len, '.');
+			seen_dot = 1;
+		} else {
+			abort();
+		}
+		s++;
+	}
+	if (res_len && res[res_len-1] == '.')
+		res_len--;
+	if (mult)
+		append_char(&res, &res_len, mult);
+	append_char(&res, &res_len, unit);
+	return res;
+}
+
 
 static char *compose(const struct chunk *c,
     const struct var *in, const struct var *out,
-    const char *s, const regmatch_t *match)
+    const char *s, const regmatch_t *match, const char *units)
 {
 	char *res = stralloc("");
-	int res_len = 0;
+	int res_len = 0, len;
 	const char *val;
+	char *tmp, *tmp2;
 	int n;
 
 	while (c) {
@@ -69,16 +120,14 @@ static char *compose(const struct chunk *c,
 			}
 			if (match[n-1].rm_so == -1)
 				yyerrorf("substring $%d out of range", n);
-#if 0
+			len = match[n-1].rm_eo-match[n-1].rm_so;
-			len = match[n-1].rm_eo-match[n-1].rm_so);
 			tmp = alloc_size(len);
 			memcpy(tmp, s+match[n-1].rm_so, len);
 			tmp[len] = 0;
-			tmp2 = canonicalize(tmp, c->unit);
+			tmp2 = canonicalize(tmp, units ? units[n-1] : 0);
 			append(&res, &res_len, tmp2);
-#endif
+			free(tmp);
-			append_n(&res, &res_len, s+match[n-1].rm_so,
+			free(tmp2);
-			    match[n-1].rm_eo-match[n-1].rm_so);
 			break;
 		default:
 			abort();
@@ -147,7 +196,7 @@ static int do_match(const char *var, const regex_t *re,
 
 static const struct subst *recurse_sub(const struct subst *sub,
     const struct var *in, const char *s, const regmatch_t *match,
-    struct var **out)
+    const char *units, struct var **out)
 {
 	const struct subst *jump;
 	regmatch_t m_tmp[10];
@@ -161,12 +210,13 @@ static const struct subst *recurse_sub(const struct subst *sub,
 			    in, *out, &val, m_tmp))
 				break;
 			jump = recurse_sub(sub->u.match.block, in, val, m_tmp,
-			    out);
+			    sub->u.match.units, out);
 			if (jump && jump != sub)
 				return jump;
 			break;
 		case st_assign:
-			tmp = compose(sub->u.assign.pat, in, *out, s, match);
+			tmp = compose(sub->u.assign.pat, in, *out, s, match,
+			    units);
 			do_assign(sub->u.assign.dst, out, tmp);
 			break;
 		case st_end:
@@ -199,7 +249,7 @@ struct var *substitute(const struct subst *sub, const struct var *in)
 			f[i] = unique(tmp);
 		}
 	}
-	recurse_sub(sub, in, NULL, NULL, &out);
+	recurse_sub(sub, in, NULL, NULL, NULL, &out);
 	return out;
 }
 

b2/subst.c

@@ -38,11 +38,33 @@ static struct subst *alloc_subst(enum subst_type type)
 }
 
 
-static char *prepare_re(const char *re)
+/*
+ * With M the SI multiplier prefixes and U the unit character, our regexp
+ * is
+ *
+ * (-?[0-9]+\.?[[0-9]*M?U?|-?[0-9]+[UM][0-9]*)
+ *
+ * The first part is for things like 10, 1.2k, 3.3V, -2mA, etc.
+ * The second part is for things like 1k20, 1R2, etc.
+ */
+
+static void unit_expr(char **res, int *res_len, char unit)
+{
+	append(res, res_len, "(-?[0-9]+\\.?[0-9]*[" MULT_CHARS "]?");
+	append_char(res, res_len, unit);
+	append(res, res_len, "?|-?[0-9]+[");
+	append_char(res, res_len, unit);
+	append(res, res_len, MULT_CHARS "][0-9]*)");
+}
+
+
+static char *prepare_re(const char *re, int *parens, char *units)
 {
 	char *res = NULL;
 	int res_len = 0;
 
+	*parens = 0;
+	memset(units, 0, 10);
 	append_char(&res, &res_len, '^');
 	while (*re) {
 		switch (*re) {
@@ -61,6 +83,16 @@ static char *prepare_re(const char *re)
 			append_n(&res, &res_len, re, 2);
 			re++;
 			break;
+		case '(':
+			(*parens)++;
+			if (re[1] == '#' && re[2] && isalpha(re[2]) &&
+			    re[3] == ')') {
+				units[*parens-1] = re[2];
+				unit_expr(&res, &res_len, re[2]);
+				re += 3;
+				break;
+			}
+			/* fall through */
 		default:
 			append_char(&res, &res_len, *re);
 		}
@@ -77,11 +109,11 @@ struct subst *subst_match(const char *src, const char *re)
 	char error[1000];
 	struct subst *sub;
 	char *tmp;
-	int err;
+	int parens, err;
 
 	sub = alloc_subst(st_match);
 	sub->u.match.src = src;
-	tmp = prepare_re(re);
+	tmp = prepare_re(re, &parens, sub->u.match.units);
 	err = regcomp(&sub->u.match.re, tmp, REG_EXTENDED);
 	free(tmp);
 	if (err) {
@@ -102,7 +134,6 @@ static void end_chunk(struct chunk ***last, const char *start, const char *s)
 	c = alloc_type(struct chunk);
 	c->type = ct_string;
 	c->u.s = stralloc_n(start, s-start);;
-	c->unit = NULL;
 	c->next = NULL;
 	**last = c;
 	*last = &c->next;
@@ -154,28 +185,9 @@ static const char *parse_var(struct chunk *c, const char *s)
 		c->u.sub = 0;
 	}
 
-	if (*t != '#') {
 	if (braced) {
-			assert(*t == '}');
+		if (*t != '}')
-			t++;
+			yyerror("invalid variable name");
-		}
-		return t;
-	}
-
-	s = ++t;
-	while (*t) {
-		if (braced && *t == '}')
-			break;
-		if (!braced && t != s)
-			break;
-		t++;
-	}
-	if (s == t)
-		yyerror("invalid unit");
-	c->unit = stralloc_n(s, t-s);
-	if (braced) {
-		if (!*t)
-			yyerror("unterminated unit");
 		t++;
 	}
 	return t;
@@ -204,7 +216,6 @@ static struct chunk *parse_pattern(const char *s)
 
 		end_chunk(&last, start, s);
 		c = alloc_type(struct chunk);
-		c->unit = NULL;
 		c->next = NULL;
 		*last = c;
 		last = &c->next;
@@ -324,18 +335,13 @@ static void dump_chunks(FILE *file, const struct chunk *c)
 			break;
 		case ct_sub:
 			if (c->u.sub)
-				fprintf(file, "${%d", c->u.sub);
+				fprintf(file, "$%d", c->u.sub);
 			else
-				fprintf(file, "${$");
+				fprintf(file, "$$");
 			break;
 		default:
 			abort();
 		}
-		if (c->type != ct_string) {
-			if (c->unit)
-				fprintf(file, "#%s", c->unit);
-			fprintf(file, "}");
-		}
 		c = c->next;
 	}
 }

b2/subst.h

@@ -31,7 +31,6 @@ struct chunk {
 		const char *var;
 		int sub; /* 0 if $$ */
 	} u;
-	const char *unit; /* NULL if no conversion specified */
 	struct chunk *next;
 };
 
@@ -50,6 +49,7 @@ struct subst {
 			const char *src;
 			regex_t re;
 			struct subst *block;
+			char units[10];
 		} match;
 		struct {
 			const char *dst;
@@ -62,6 +62,9 @@ struct subst {
 };
 
 
+#define	MULT_CHARS	"GMkmunpf"
+
+
 struct subst *subst_match(const char *src, const char *re);
 struct subst *subst_assign(const char *dst, const char *pat);
 struct subst *subst_end(void);