From 9fe6cd7c0e92ac5c5a711ed41e414ebbc1d50ad8 Mon Sep 17 00:00:00 2001
From: iamcheeseman <dev@iamcheeseman.net>
Date: Tue, 14 Apr 2026 12:50:32 -0400
Subject: microscript: string indexing

---
 uscript/vm.c | 65 +++++++++++++++++++++++++++++++++++++++++++-----------------
 1 file changed, 47 insertions(+), 18 deletions(-)

(limited to 'uscript')

diff --git a/uscript/vm.c b/uscript/vm.c
index 26fccbe..e01d17d 100644
--- a/uscript/vm.c
+++ b/uscript/vm.c
@@ -76,6 +76,51 @@ void close_upvals(struct us_val *to)
         vm.open_upvals = upval;
 }
 
+static
+void index_val(struct us_val idx_val, struct us_val idxee_val)
+{
+        switch (idxee_val.type) {
+        case VAL_ARR: {
+                if (idx_val.type != VAL_NUM)
+                        log_fatal(1, "arrays must be indexed by numbers");
+                int idx = (int)get_num(idx_val);
+                struct us_arr *arr = get_arr(idxee_val);
+                if (idx < 0)
+                        idx += da_len(arr->e);
+                if (idx < 0 || idx >= da_len(arr->e)) {
+                        log_fatal(
+                                1,
+                                "index out of range (%d/%d)",
+                                idx,
+                                da_len(arr->e) - 1
+                        );
+                }
+                vm_push(arr->e[idx]);
+                break;
+        }
+        case VAL_STR: {
+                if (idx_val.type != VAL_NUM)
+                        log_fatal(1, "strings must be indexed by numbers");
+                int idx = (int)get_num(idx_val);
+                struct us_str *str = get_str(idxee_val);
+                if (idx < 0)
+                        idx += str->len;
+                if (idx < 0 || (size_t)idx >= str->len) {
+                        log_fatal(
+                                1,
+                                "index out of range (%d/%d)",
+                                idx,
+                                str->len - 1
+                        );
+                }
+                vm_push(wrap_str(copy_str(&str->chars[idx], 1)));
+                break;
+        }
+        default:
+                log_fatal(1, "cannot index that value");
+                break;
+        }
+}
 
 static
 void call_val(struct us_val callee, int argc) 
@@ -218,24 +263,8 @@ void us_exec(struct us_func *func)
                         break;
                 case BC_GET_INDEX: {
                         struct us_val idx_val = vm_pop();
-                        struct us_val arr_val = vm_pop();
-                        if (idx_val.type != VAL_NUM)
-                                log_fatal(1, "index type must be number");
-                        if (arr_val.type != VAL_ARR)
-                                log_fatal(1, "only arrays can be indexed");
-                        int idx = (int)get_num(idx_val);
-                        struct us_arr *arr = get_arr(arr_val);
-                        if (idx < 0)
-                                idx += da_len(arr->e);
-                        if (idx < 0 || idx >= da_len(arr->e)) {
-                                log_fatal(
-                                        1,
-                                        "index out of range (%d/%d)",
-                                        idx,
-                                        da_len(arr->e) - 1
-                                );
-                        }
-                        vm_push(arr->e[idx]);
+                        struct us_val idxee_val = vm_pop();
+                        index_val(idx_val, idxee_val);
                         break;
                 }
                 case BC_SET_INDEX: {
-- 
cgit v1.3-2-g0d8e