diff --git a/eeshow/file.c b/eeshow/file.c
index 5635a0a..6abea40 100644
--- a/eeshow/file.c
+++ b/eeshow/file.c
@@ -21,41 +21,27 @@
 #include "file.h"
 
 
-bool file_cat(void *user, const char *line)
+bool file_cat(const struct file *file, void *user, const char *line)
 {
 	printf("%s\n", line);
 	return 1;
 }
 
 
-static void read_from_file(FILE *file,
-    bool (*parse)(void *user, const char *line), void *user)
+void file_open(struct file *file, const char *name,
+    const struct file *related)
 {
-	char buf[1000];
-	char *nl;
-
-	while (fgets(buf, sizeof(buf), file)) {
-		nl = strchr(buf, '\n');
-		if (nl)
-			*nl = 0;
-		if (!parse(user, buf))
-			break;
-	}
-}
-
-
-void file_read(const char *name, bool (*parse)(void *user, const char *line),
-    void *user)
-{
-	FILE *file;
 	char *colon, *tmp;
 
-	file = fopen(name, "r");
-	if (file) {
+	file->name = stralloc(name);
+	file->lineno = 0;
+	file->related = related;
+	file->vcs = NULL;
+
+	file->file = fopen(name, "r");
+	if (file->file) {
 		if (verbose)
 			fprintf(stderr, "reading %s\n", name);
-		read_from_file(file, parse, user);
-		fclose(file);
 		return;
 	}
 
@@ -71,6 +57,42 @@ void file_read(const char *name, bool (*parse)(void *user, const char *line),
 
 	tmp = stralloc(name);
 	tmp[colon - name] = 0;
-	vcs_git_read(tmp, colon + 1, parse, user);
+	file->vcs = vcs_git_open(tmp, colon + 1);
+	if (!file->vcs) {
+		fprintf(stderr, "could not open %s:%s\n", tmp, colon + 1);
+		exit(1);
+	}
 	free(tmp);
 }
+
+
+void file_read(struct file *file,
+    bool (*parse)(const struct file *file, void *user, const char *line),
+    void *user)
+{
+	char buf[1000];
+	char *nl;
+
+	if (file->vcs) {
+		vcs_read(file->vcs, file, parse, user);
+		return;
+	}
+	while (fgets(buf, sizeof(buf), file->file)) {
+		nl = strchr(buf, '\n');
+		if (nl)
+			*nl = 0;
+		file->lineno++;
+		if (!parse(file, user, buf))
+			break;
+	}
+}
+
+
+void file_close(struct file *file)
+{
+	if (file->file)
+		fclose(file->file);
+	if (file->vcs)
+		vcs_close(file->vcs);
+	free((char *) file->name);
+}
diff --git a/eeshow/file.h b/eeshow/file.h
index a6cc170..43db8b7 100644
--- a/eeshow/file.h
+++ b/eeshow/file.h
@@ -14,9 +14,25 @@
 #define	FILE_H
 
 #include <stdbool.h>
+#include <stdio.h>
 
-bool file_cat(void *user, const char *line);
-void file_read(const char *name, bool (*parse)(void *user, const char *line),
+
+struct file {
+	FILE *file;		/* NULL if using a version control system */
+	void *vcs;		/* VCS descriptor or NULL */
+	const char *name;	/* name/designator given to file_open */
+	unsigned lineno;
+	const struct file *related; /* NULL if not related to anything */
+};
+
+
+bool file_cat(const struct file *file, void *user, const char *line);
+
+void file_open(struct file *file, const char *name,
+    const struct file *related);
+void file_read(struct file *file,
+    bool (*parse)(const struct file *file, void *user, const char *line),
     void *user);
+void file_close(struct file *file);
 
 #endif /* !FILE_H */
diff --git a/eeshow/git-file.c b/eeshow/git-file.c
index bd66d73..261de53 100644
--- a/eeshow/git-file.c
+++ b/eeshow/git-file.c
@@ -22,9 +22,16 @@
 
 #include "util.h"
 #include "main.h"
+#include "file.h"
 #include "git-file.h"
 
 
+struct vcs_git {
+	const void *data;
+	unsigned size;
+};
+
+
 static git_repository *select_repo(const char *path)
 {
 	git_repository *repo = NULL;
@@ -305,48 +312,27 @@ static const void *get_data(git_repository *repo, git_tree_entry *entry,
 
 
 static bool send_line(const char *s, unsigned len,
-    bool (*parse)(void *user, const char *line), void *user)
+    bool (*parse)(const struct file *file, void *user, const char *line),
+    void *user, const struct file *file)
 {
 	char *tmp = alloc_size(len + 1);
 	bool res;
 
 	memcpy(tmp, s, len);
 	tmp[len] = 0;
-	res = parse(user, tmp);
+	res = parse(file, user, tmp);
 	free(tmp);
 	return res;
 }
 
 
-static void send_data(const char *data, unsigned size,
-    bool (*parse)(void *user, const char *line), void *user)
-{
-	const char *end = data + size;
-	const char *p = data;
-	const char *nl;
-
-	while (p != end) {
-		nl = memchr(p, '\n', end - p);
-		if (!nl) {
-			send_line(p, end - p, parse, user);
-			return;
-		}
-		if (!send_line(p, nl - p, parse, user))
-			return;
-		p = nl + 1;
-	}
-}
-
-
-void vcs_git_read(const char *revision, const char *name, 
-    bool (*parse)(void *user, const char *line), void *user)
+struct vcs_git *vcs_git_open(const char *revision, const char *name)
 {
 	static bool initialized = 0;
+	struct vcs_git *vcs_git = alloc_type(struct vcs_git);
 	git_repository *repo;
 	git_tree *tree;
 	git_tree_entry *entry;
-	const void *data;
-	unsigned size;
 
 	if (!initialized) {
 		git_libgit2_init();
@@ -366,6 +352,37 @@ void vcs_git_read(const char *revision, const char *name,
 	entry = find_file(repo, tree, name);
 	if (verbose)
 		fprintf(stderr, "reading %s:%s\n", revision, name);
-	data = get_data(repo, entry, &size);
-	send_data(data, size, parse, user);
+
+	vcs_git->data = get_data(repo, entry, &vcs_git->size);
+
+	return vcs_git;
+}
+
+
+void vcs_git_read(void *ctx, struct file *file,
+    bool (*parse)(const struct file *file, void *user, const char *line), 
+    void *user)
+{
+	const struct vcs_git *vcs_git = ctx;
+	const char *end = vcs_git->data + vcs_git->size;
+	const char *p = vcs_git->data;
+	const char *nl;
+
+	while (p != end) {
+		nl = memchr(p, '\n', end - p);
+		file->lineno++;
+		if (!nl) {
+			send_line(p, end - p, parse, user, file);
+			return;
+		}
+		if (!send_line(p, nl - p, parse, user, file))
+			return;
+		p = nl + 1;
+	}
+}
+
+
+void vcs_git_close(void *ctx)
+{
+	free(ctx);
 }
diff --git a/eeshow/git-file.h b/eeshow/git-file.h
index 503a563..9214d93 100644
--- a/eeshow/git-file.h
+++ b/eeshow/git-file.h
@@ -16,7 +16,23 @@
 #include <stdbool.h>
 
 
-void vcs_git_read(const char *revision, const char *name,
-    bool (*parse)(void *user, const char *line), void *user);
+/*
+ * future-proofing: if someone wants to add back-ends for other version control
+ * systems, the identifiers will already be there.
+ */
+
+#define	vcs_open	vcs_git_open
+#define	vcs_read	vcs_git_read
+#define	vcs_close	vcs_git_close
+
+
+struct vcs_git;
+struct file;
+
+struct vcs_git *vcs_git_open(const char *revision, const char *name);
+void vcs_git_read(void *ctx, struct file *file,
+    bool (*parse)(const struct file *file, void *user, const char *line),
+    void *user);
+void vcs_git_close(void *ctx);
 
 #endif /* !GIT_FILE_H */
diff --git a/eeshow/lib-parse.c b/eeshow/lib-parse.c
index 21d37ff..5946d31 100644
--- a/eeshow/lib-parse.c
+++ b/eeshow/lib-parse.c
@@ -130,7 +130,8 @@ static bool parse_arc(struct lib_obj *obj, const char *line)
 /* ----- Library parser ---------------------------------------------------- */
 
 
-static bool lib_parse_line(void *user, const char *line)
+static bool lib_parse_line(const struct file *file,
+    void *user, const char *line)
 {
 	struct lib *lib = user;
 	int n = 0;
@@ -253,11 +254,15 @@ static bool lib_parse_line(void *user, const char *line)
 }
 
 
-void lib_parse(struct lib *lib, const char *file)
+void lib_parse(struct lib *lib, const char *name)
 {
+	struct file file;
+
 	lib->state = lib_skip;
 	lib->lineno = 0;
-	file_read(file, lib_parse_line, lib);
+	file_open(&file, name, NULL);
+	file_read(&file, lib_parse_line, lib);
+	file_close(&file);
 }
 
 
diff --git a/eeshow/lib.h b/eeshow/lib.h
index 4f1e9f0..52c1746 100644
--- a/eeshow/lib.h
+++ b/eeshow/lib.h
@@ -118,7 +118,7 @@ const struct comp *lib_find(const struct lib *lib, const char *name);
 bool lib_field_visible(const struct comp *comp, int n);
 void lib_render(const struct comp *comp, unsigned unit, const int m[6]);
 
-void lib_parse(struct lib *lib, const char *file);
+void lib_parse(struct lib *lib, const char *name);
 void lib_init(struct lib *lib);
 
 #endif /* !LIB_H */
diff --git a/eeshow/main.c b/eeshow/main.c
index b38761a..8b947de 100644
--- a/eeshow/main.c
+++ b/eeshow/main.c
@@ -109,9 +109,13 @@ int main(int argc, char *const *argv)
 		}
 
 	if (cat) {
+		struct file file;
+
 		if (argc != optind)
 			usage(*argv);
-		file_read(cat, file_cat, NULL);
+		file_open(&file, cat, NULL);
+		file_read(&file, file_cat, NULL);
+		file_close(&file);
 		return 0;
 	}
 
diff --git a/eeshow/sch-parse.c b/eeshow/sch-parse.c
index e47ac49..7a2c8c4 100644
--- a/eeshow/sch-parse.c
+++ b/eeshow/sch-parse.c
@@ -293,7 +293,7 @@ static struct sheet *new_sheet(struct sch_ctx *ctx)
 }
 
 
-static bool parse_line(void *user, const char *line);
+static bool parse_line(const struct file *file, void *user, const char *line);
 
 
 static void recurse_sheet(struct sch_ctx *ctx)
@@ -301,6 +301,7 @@ static void recurse_sheet(struct sch_ctx *ctx)
 	struct sch_obj **saved_next_obj = ctx->next_obj;
 	const char *parent = ctx->file->name;
 	char *tmp = NULL;
+	struct file file;
 	struct sch_file dsc = {
 		.name	= ctx->obj.u.sheet.file,
 		.lineno	= 0,
@@ -326,14 +327,16 @@ static void recurse_sheet(struct sch_ctx *ctx)
 	new_sheet(ctx);
 	ctx->file = &dsc;
 	ctx->state = sch_descr;
-	file_read(dsc.name, parse_line, ctx);
+	file_open(&file, dsc.name, NULL);
+	file_read(&file, parse_line, ctx);
+	file_close(&file);
 	ctx->file = dsc.parent;
 	ctx->next_obj = saved_next_obj;
 	free(tmp);
 }
 
 
-static bool parse_line(void *user, const char *line)
+static bool parse_line(const struct file *file, void *user, const char *line)
 {
 	struct sch_ctx *ctx = user;
 	struct sch_obj *obj = &ctx->obj;
@@ -538,17 +541,20 @@ static bool parse_line(void *user, const char *line)
 }
 
 
-void sch_parse(struct sch_ctx *ctx, const char *file, const struct lib *lib)
+void sch_parse(struct sch_ctx *ctx, const char *name, const struct lib *lib)
 {
+	struct file file;
 	struct sch_file dsc = {
-		.name	= file,
+		.name	= name,
 		.lineno	= 0,
 		.parent	= NULL,
 	};
 
 	ctx->file = &dsc;
 	ctx->lib = lib;
-	file_read(file, parse_line, ctx);
+	file_open(&file, name, NULL);
+	file_read(&file, parse_line, ctx);
+	file_close(&file);
 }
 
 
diff --git a/eeshow/sch.h b/eeshow/sch.h
index b1e2d70..7f036ce 100644
--- a/eeshow/sch.h
+++ b/eeshow/sch.h
@@ -117,7 +117,7 @@ struct sch_ctx {
 void decode_alignment(struct text *txt, char hor, char vert);
 
 void sch_render(const struct sheet *sheet);
-void sch_parse(struct sch_ctx *ctx, const char *file, const struct lib *lib);
+void sch_parse(struct sch_ctx *ctx, const char *name, const struct lib *lib);
 void sch_init(struct sch_ctx *ctx, bool recurse);
 
 #endif /* !SCH_H */