treewide: implement strict assignment mode

Signed-off-by: Jo-Philipp Wich <jo@mein.io>

3 files changed, 21 insertions, 4 deletions

diff --git a/ast.h b/ast.h
index cac75d2..6f2b12c 100644
--- a/ast.h
+++ b/ast.h
@@ -82,6 +82,7 @@ struct ut_state {
 	uint8_t srand_called:1;
 	uint8_t trim_blocks:1;
 	uint8_t lstrip_blocks:1;
+	uint8_t strict_declarations:1;
 	size_t off;
 	enum ut_block_type blocktype;
 	struct {
diff --git a/eval.c b/eval.c
index 954f596..4410d2d 100644
--- a/eval.c
+++ b/eval.c
@@ -303,8 +303,14 @@ ut_getref(struct ut_state *state, uint32_t off, struct json_object **key)
 
 			next = ut_getscope(state, ++i);
 
-			if (!next)
+			if (!next) {
+				if (state->strict_declarations)
+					ut_throw(state, off,
+					         "Reference error: access to undeclared variable %s",
+					         json_object_get_string(op->val));
+
 				break;
+			}
 
 			scope = next;
 		}
@@ -1356,6 +1362,11 @@ ut_execute_op(struct ut_state *state, uint32_t off)
 		ut_putval(state->ctx);
 		state->ctx = NULL;
 
+		if (state->strict_declarations && scope == NULL) {
+			ut_throw(state, off, "Reference error: %s is not defined",
+			         json_object_get_string(op->val));
+		}
+
 		val = ut_getval(scope, key);
 		ut_putval(scope);
 
diff --git a/main.c b/main.c
index 68b39c1..18db4a7 100644
--- a/main.c
+++ b/main.c
@@ -38,13 +38,14 @@ print_usage(char *app)
 {
 	printf(
 	"== Usage ==\n\n"
-	"  # %s [-d] [-l] [-r] {-i <file> | -s \"utpl script...\"}\n"
+	"  # %s [-d] [-l] [-r] [-S] {-i <file> | -s \"utpl script...\"}\n"
 	"  -h, --help	Print this help\n"
 	"  -i file	Specify an utpl script to parse\n"
 	"  -s \"utpl script...\"	Specify an utpl code fragment to parse\n"
 	"  -d Instead of executing the script, dump the resulting AST as dot\n"
 	"  -l Do not strip leading block whitespace\n"
-	"  -r Do not trim trailing block newlines\n",
+	"  -r Do not trim trailing block newlines\n"
+	"  -S Enable strict mode\n",
 		app);
 }
 
@@ -198,7 +199,7 @@ main(int argc, char **argv)
 	state->lstrip_blocks = 1;
 	state->trim_blocks = 1;
 
-	while ((opt = getopt(argc, argv, "dhlri:s:")) != -1)
+	while ((opt = getopt(argc, argv, "dhlrSi:s:")) != -1)
 	{
 		switch (opt) {
 		case 'h':
@@ -231,6 +232,10 @@ main(int argc, char **argv)
 		case 's':
 			source = optarg;
 			break;
+
+		case 'S':
+			state->strict_declarations = 1;
+			break;
 		}
 	}