From 5f8462fe34f8c6979b0d305f611820245cc31cf7 Mon Sep 17 00:00:00 2001
From: Laria Carolin Chabowski <laria@laria.me>
Date: Thu, 10 Feb 2022 22:39:39 +0100
Subject: [PATCH] Add apfl_stackidx typedef

This makes it clear that a value of that type is meant as an index into the
stack.
---
 src/apfl.h |  4 +++-
 src/eval.c | 16 ++++++++--------
 2 files changed, 11 insertions(+), 9 deletions(-)

diff --git a/src/apfl.h b/src/apfl.h
index c4ca0a0..f4974fb 100644
--- a/src/apfl.h
+++ b/src/apfl.h
@@ -565,6 +565,8 @@ struct apfl_expr apfl_parser_get_expr(apfl_parser_ptr);
 struct apfl_ctx_data;
 typedef struct apfl_ctx_data *apfl_ctx;
 
+typedef int apfl_stackidx;
+
 enum apfl_result {
     APFL_RESULT_OK, // Evaluation succeeded, value is on the stack
 
@@ -581,7 +583,7 @@ void apfl_ctx_destroy(apfl_ctx);
 
 enum apfl_result apfl_eval(apfl_ctx, struct apfl_expr);
 
-void apfl_debug_print_val(apfl_ctx, int, FILE *);
+void apfl_debug_print_val(apfl_ctx, apfl_stackidx, FILE *);
 
 #ifdef __cplusplus
 }
diff --git a/src/eval.c b/src/eval.c
index bd2a266..55186cd 100644
--- a/src/eval.c
+++ b/src/eval.c
@@ -230,7 +230,7 @@ stack_push(apfl_ctx ctx, struct apfl_value value)
 }
 
 static bool
-stack_check_index(apfl_ctx ctx, int *index)
+stack_check_index(apfl_ctx ctx, apfl_stackidx *index)
 {
     if (*index < 0) {
         if ((size_t)-*index > ctx->stack_len) {
@@ -247,7 +247,7 @@ stack_check_index(apfl_ctx ctx, int *index)
 }
 
 static bool
-stack_pop(apfl_ctx ctx, struct apfl_value *value, int index)
+stack_pop(apfl_ctx ctx, struct apfl_value *value, apfl_stackidx index)
 {
     if (!stack_check_index(ctx, &index)) {
         return false;
@@ -271,7 +271,7 @@ stack_pop(apfl_ctx ctx, struct apfl_value *value, int index)
 }
 
 static struct apfl_value
-stack_must_pop(apfl_ctx ctx, int index)
+stack_must_pop(apfl_ctx ctx, apfl_stackidx index)
 {
     struct apfl_value value;
     assert(stack_pop(ctx, &value, index));
@@ -279,7 +279,7 @@ stack_must_pop(apfl_ctx ctx, int index)
 }
 
 static bool
-stack_get(apfl_ctx ctx, struct apfl_value *value, int index)
+stack_get(apfl_ctx ctx, struct apfl_value *value, apfl_stackidx index)
 {
     if (!stack_check_index(ctx, &index)) {
         return false;
@@ -291,7 +291,7 @@ stack_get(apfl_ctx ctx, struct apfl_value *value, int index)
 }
 
 static struct apfl_value
-stack_must_get(apfl_ctx ctx, int index)
+stack_must_get(apfl_ctx ctx, apfl_stackidx index)
 {
     struct apfl_value value;
     assert(stack_get(ctx, &value, index));
@@ -299,7 +299,7 @@ stack_must_get(apfl_ctx ctx, int index)
 }
 
 static bool
-stack_drop(apfl_ctx ctx, int index)
+stack_drop(apfl_ctx ctx, apfl_stackidx index)
 {
     struct apfl_value value;
     if (!stack_pop(ctx, &value, index)) {
@@ -310,7 +310,7 @@ stack_drop(apfl_ctx ctx, int index)
 }
 
 static void
-stack_must_drop(apfl_ctx ctx, int index)
+stack_must_drop(apfl_ctx ctx, apfl_stackidx index)
 {
     assert(stack_drop(ctx, index));
 }
@@ -1420,7 +1420,7 @@ apfl_eval(apfl_ctx ctx, struct apfl_expr expr)
 }
 
 void
-apfl_debug_print_val(apfl_ctx ctx, int index, FILE *f)
+apfl_debug_print_val(apfl_ctx ctx, apfl_stackidx index, FILE *f)
 {
     struct apfl_value value;
     if (!stack_pop(ctx, &value, index)) {