Phase 3: file I/O, PRINT USING, SAVE/LOAD, MID$ assignment, graphics stubs

Add OPEN/CLOSE with both modern (OPEN "f" FOR OUTPUT AS #n) and compact (OPEN "O",#n,"f") syntaxes. PRINT#, WRITE#, INPUT#, LINE INPUT# for sequential file access. EOF() now returns real file status with peek-ahead. LOC/LOF return approximate values. PRINT USING with numeric (#, ., +, -, $$, **, ^^^^, comma grouping) and string (!, &, \ \) format specifiers. Shared by PRINT USING and PRINT# USING. SAVE (ASCII), LOAD (with ,R auto-run), and MERGE for program persistence. MID$ assignment (MID$(var$, start [,len]) = expr) for in-place string modification. Works with both scalar variables and array elements. Graphics stubs for SCREEN, PSET, PRESET, LINE, CIRCLE, DRAW, PAINT, VIEW, WINDOW, PALETTE - parse and discard arguments so graphics-heavy programs don't crash. SYSTEM and NEW/CLEAR now close all open files. Version bumped to 0.3.0. 22 tests pass (16 existing + 6 new).
2026-02-10 11:53:28 -05:00
parent 616259537a
commit c2d73e9c24
16 changed files with 1443 additions and 7 deletions
@@ -0,0 +1,145 @@
+#include "gwbasic.h"
+#include <string.h>
+#include <stdlib.h>
+#include <ctype.h>
+
+/* SAVE "filename" [,A] - save program as ASCII text */
+void gw_stmt_save(void)
+{
+    gw_skip_spaces();
+    gw_value_t fname_val = gw_eval_str();
+    char *filename = gw_str_to_cstr(&fname_val.sval);
+    gw_str_free(&fname_val.sval);
+
+    /* We only support ASCII saves (,A is optional/default) */
+    gw_skip_spaces();
+    if (gw_chrgot() == ',') {
+        gw_chrget();
+        gw_skip_spaces();
+        /* Skip A or P flag */
+        if (gw_is_letter(gw_chrgot()))
+            gw_chrget();
+    }
+
+    FILE *fp = fopen(filename, "w");
+    if (!fp) {
+        free(filename);
+        gw_error(ERR_IO);
+    }
+    free(filename);
+
+    char listbuf[512];
+    program_line_t *p = gw.prog_head;
+    while (p) {
+        gw_list_line(p->tokens, p->len, listbuf, sizeof(listbuf));
+        fprintf(fp, "%u %s\n", p->num, listbuf);
+        p = p->next;
+    }
+    fclose(fp);
+}
+
+/* Helper: load lines from a file into the program, optionally clearing first */
+static void load_from_file(const char *filename, bool clear)
+{
+    FILE *fp = fopen(filename, "r");
+    if (!fp)
+        gw_error(ERR_FF);
+
+    if (clear) {
+        gw_free_program();
+        gw_vars_clear();
+        gw_arrays_clear();
+        gw_file_close_all();
+        memset(gw.fn_defs, 0, sizeof(gw.fn_defs));
+        gw.for_sp = 0;
+        gw.gosub_sp = 0;
+        gw.while_sp = 0;
+        gw.data_ptr = NULL;
+        gw.data_line_ptr = NULL;
+        gw.cont_text = NULL;
+        gw.cont_line = NULL;
+        gw.on_error_line = 0;
+        gw.in_error_handler = false;
+    }
+
+    char buf[256];
+    while (fgets(buf, sizeof(buf), fp)) {
+        int len = strlen(buf);
+        while (len > 0 && (buf[len - 1] == '\n' || buf[len - 1] == '\r'))
+            buf[--len] = '\0';
+        if (buf[0] == '\0') continue;
+
+        int clen = gw_crunch(buf, gw.kbuf, sizeof(gw.kbuf));
+
+        /* Parse line number from tokenized form */
+        uint8_t *tp = gw.kbuf;
+        while (*tp == ' ') tp++;
+        uint8_t tok = *tp;
+        uint16_t num;
+        int skip = 0;
+
+        if (tok >= 0x11 && tok <= 0x1A) {
+            num = tok - 0x11;
+            skip = (tp - gw.kbuf) + 1;
+        } else if (tok == 0x0F) {
+            num = tp[1];
+            skip = (tp - gw.kbuf) + 2;
+        } else if (tok == 0x0E) {
+            num = (uint16_t)(tp[1] | (tp[2] << 8));
+            skip = (tp - gw.kbuf) + 3;
+        } else {
+            continue;  /* skip non-numbered lines */
+        }
+
+        int data_len = clen - skip;
+        uint8_t *data = gw.kbuf + skip;
+        while (*data == ' ' && data_len > 0) { data++; data_len--; }
+
+        if (data_len > 0 && *data != 0)
+            gw_store_line(num, data, data_len);
+    }
+    fclose(fp);
+}
+
+/* LOAD "filename" [,R] */
+void gw_stmt_load(void)
+{
+    gw_skip_spaces();
+    gw_value_t fname_val = gw_eval_str();
+    char *filename = gw_str_to_cstr(&fname_val.sval);
+    gw_str_free(&fname_val.sval);
+
+    bool run_after = false;
+    gw_skip_spaces();
+    if (gw_chrgot() == ',') {
+        gw_chrget();
+        gw_skip_spaces();
+        if (gw_is_letter(gw_chrgot()) && toupper(gw_chrgot()) == 'R') {
+            run_after = true;
+            gw_chrget();
+        }
+    }
+
+    load_from_file(filename, true);
+    free(filename);
+
+    if (run_after && gw.prog_head) {
+        gw.cur_line = gw.prog_head;
+        gw.text_ptr = gw.prog_head->tokens;
+        gw.cur_line_num = gw.prog_head->num;
+        gw.running = true;
+        gw_run_loop();
+    }
+}
+
+/* MERGE "filename" - load without clearing existing program */
+void gw_stmt_merge(void)
+{
+    gw_skip_spaces();
+    gw_value_t fname_val = gw_eval_str();
+    char *filename = gw_str_to_cstr(&fname_val.sval);
+    gw_str_free(&fname_val.sval);
+
+    load_from_file(filename, false);
+    free(filename);
+}