refactor: make interpreter portable with static pools and I/O hooks

Co-authored-by: aider (openrouter/moonshotai/kimi-k2.6) <aider@aider.chat>

forth_interp.c

@@ -19,17 +19,12 @@ char* next_token(void) {
 }
 
 // Ensure compile_buf has room for at least 'needed' more cells
-void ensure_compile_cap(int32_t needed) {
-    while (compile_idx + needed > compile_cap) {
-        int32_t new_cap = compile_cap ? compile_cap * 2 : 256;
-        Cell *tmp = realloc(compile_buf, new_cap * sizeof(Cell));
-        if (!tmp) {
-            fprintf(stderr, "Out of memory\n");
-            exit(1);
-        }
-        compile_buf = tmp;
-        compile_cap = new_cap;
+int ensure_compile_cap(int32_t needed) {
+    if (compile_idx + needed > compile_cap) {
+        forth_printf("Compile buffer overflow\n");
+        return 0;
     }
+    return 1;
 }
 
 // Inner interpreter (unchanged)
@@ -62,7 +57,7 @@ void process_token(const char* token) {
                     w->code(w);
                 }
             } else { // Compile normal word
-                ensure_compile_cap(1);
+                if (!ensure_compile_cap(1)) return;
                 compile_buf[compile_idx++] = (Cell){.word = w};
             }
         }
@@ -74,27 +69,30 @@ void process_token(const char* token) {
                 data_push((int64_t)v);
             } else { // Compile lit + number
                 if (!w_lit) {
-                    fprintf(stderr, "Fatal: lit word not found\n");
+                    forth_printf("Fatal: lit word not found\n");
                     return;
                 }
-                ensure_compile_cap(2);
+                if (!ensure_compile_cap(2)) return;
                 compile_buf[compile_idx++] = (Cell){.word = w_lit};
                 compile_buf[compile_idx++] = (Cell){.num = (int64_t)v};
             }
         } else {
-            printf("Unknown word: '%s'\n", token);
+            forth_printf("Unknown word: '%s'\n", token);
         }
     }
 }
 
 void outer_interpreter(void) {
+    static char line_buf[256];
     while (1) {
-        printf("ok ");
-        fflush(stdout);
-        ssize_t n = getline(&input_buf, &input_buf_cap, stdin);
-        if (n < 0) {
+        forth_printf("ok ");
+        forth_fflush();
+        if (fgets(line_buf, sizeof(line_buf), stdin) == NULL) {
             break;
         }
+        input_buf = line_buf;
+        input_buf_cap = sizeof(line_buf);
+        size_t n = strlen(input_buf);
         if (n > 0 && input_buf[n - 1] == '\n') {
             input_buf[n - 1] = '\0';
         }
@@ -104,5 +102,5 @@ void outer_interpreter(void) {
             process_token(tok);
         }
     }
-    printf("\n");
+    forth_printf("\n");
 }