From 6fa4569a644090e04ff4dd1ae536c4d2b776668b Mon Sep 17 00:00:00 2001
From: Kimplul <kimi.h.kuparinen@gmail.com>
Date: Thu, 13 Aug 2026 20:15:01 +0300
Subject: allow reading from file

---
 src/fwdscript.c | 56 ++++++++++++++++++++++++++++++++++++++++++++++++--------
 1 file changed, 48 insertions(+), 8 deletions(-)

(limited to 'src/fwdscript.c')

diff --git a/src/fwdscript.c b/src/fwdscript.c
index 6b47ca0..7b1de26 100644
--- a/src/fwdscript.c
+++ b/src/fwdscript.c
@@ -1,9 +1,11 @@
 #include <err.h>
 #include <stdio.h>
 #include <ctype.h>
+#include <unistd.h>
 #include <stdlib.h>
 #include <stdint.h>
 #include <string.h>
+#include <sys/mman.h>
 
 #define TODO() errx(EXIT_FAILURE, "%s:%d: todo", __FILE__,  __LINE__)
 
@@ -1521,21 +1523,56 @@ static void fwdscript_destroy(struct fwdscript *s)
 	fwdbuiltins_destroy(&s->builtins);
 }
 
-int main()
+static const char *read_file(const char *fname)
 {
+	FILE *f = fopen(fname, "rb");
+	if (!f)
+		err(EXIT_FAILURE, "failed opening %s", fname);
+
+	if (fseek(f, 0, SEEK_END) < 0)
+		err(EXIT_FAILURE, "failed seeking %s", fname);
+
+	long sz = ftell(f);
+	if (sz < 0)
+		err(EXIT_FAILURE, "failed telling %s", fname);
+
+	if (fseek(f, 0, SEEK_SET) < 0)
+		err(EXIT_FAILURE, "failed rewinding %s", fname);
+
+	char *buf = malloc(sz + 1);
+	if (!buf)
+		err(EXIT_FAILURE, "failed allocating buf for %s", fname);
+
+	if ((long)fread(buf, 1, sz, f) != sz)
+		err(EXIT_FAILURE, "failed reading file %s", fname);
+
+	/* trailing zero */
+	buf[sz] = '\0';
+
+	fclose(f);
+	return buf;
+}
+
+int main(int argc, char *argv[])
+{
+	/* a bit silly but good enough for testing */
+	const char *buf =
+	"main /tbl args {\n"
+	"	get args 0 => {abort \"impossible\"}\n"
+	"	=> /str line;\n"
+	"	print line\n"
+	"}\n";
+
+	if (argc == 2)
+		buf = read_file(argv[1]);
+
 	int ret = 0;
 	struct fwdscript inst = fwdscript_create();
 
 	ret = fwdscript_register_builtins(&inst);
 	assert(ret == 0);
 
-	ret = fwdscript_parse(&inst,
-			"main /tbl args {\n"
-			"	get args 0 => {abort \"impossible\"}\n"
-			"	=> /str line;\n"
-			"	print line\n"
-			"}\n");
-
+	ret = fwdscript_parse(&inst, buf);
 	assert(ret == 0);
 
 	struct fwdvals args = fwdvals_create(1);
@@ -1546,4 +1583,7 @@ int main()
 	/* string should've been consumed by main so we shouldn't try to free it */
 	fwdvals_destroy(&args);
 	fwdscript_destroy(&inst);
+
+	if (argc == 2)
+		free((void *)buf);
 }
-- 
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