better parser error reporting

source/cell.c

@@ -114,12 +114,19 @@ static int print_tree_errors(cJSON *root) {
   cJSON *fname = cJSON_GetObjectItemCaseSensitive(root, "filename");
   if (cJSON_IsString(fname))
     filename = fname->valuestring;
+  int prev_line = -1;
+  const char *prev_msg = NULL;
   cJSON *e;
   cJSON_ArrayForEach(e, errors) {
     const char *msg = cJSON_GetStringValue(
       cJSON_GetObjectItemCaseSensitive(e, "message"));
     cJSON *line = cJSON_GetObjectItemCaseSensitive(e, "line");
     cJSON *col = cJSON_GetObjectItemCaseSensitive(e, "column");
+    int cur_line = cJSON_IsNumber(line) ? (int)line->valuedouble : -1;
+    if (prev_msg && msg && cur_line == prev_line && strcmp(msg, prev_msg) == 0)
+      continue;
+    prev_line = cur_line;
+    prev_msg = msg;
     if (msg && cJSON_IsNumber(line) && cJSON_IsNumber(col))
       fprintf(stderr, "%s:%d:%d: error: %s\n",
         filename, (int)line->valuedouble, (int)col->valuedouble, msg);

source/quickjs.c

@@ -28290,6 +28290,7 @@ typedef struct ASTParseState {
   int function_nr;
   cJSON *errors;  /* array of error objects */
   int has_error;
+  int error_count;
   int in_disruption;
   char *decoded_str;  /* allocated buffer for decoded string escapes */
   GetLineColCache lc_cache;
@@ -28396,6 +28397,9 @@ static void ast_node_end (ASTParseState *s, cJSON *node, const uint8_t *end_ptr)
 }
 
 static void ast_error (ASTParseState *s, const uint8_t *ptr, const char *fmt, ...) {
+  if (s->error_count >= 5) return;
+  s->error_count++;
+
   va_list ap;
   char buf[256];
   int line, col;
@@ -29846,11 +29850,11 @@ static cJSON *ast_parse_primary (ASTParseState *s) {
   default:
     /* Report syntax error with token info */
     if (s->token_val >= 32 && s->token_val < 127) {
-      ast_error (s, start, "unexpected token '%c'", s->token_val);
+      ast_error (s, start, "unexpected '%c' in expression", s->token_val);
     } else if (s->token_val == TOK_EOF) {
       ast_error (s, start, "unexpected end of input");
     } else {
-      ast_error (s, start, "unexpected token");
+      ast_error (s, start, "unexpected token (keyword or operator) where expression expected");
     }
     ast_next_token (s);
     return NULL;
@@ -30689,7 +30693,7 @@ static cJSON *ast_parse_statement (ASTParseState *s) {
       cJSON_AddItemToObject (node, "expression", expr);
       ast_node_end (s, node, s->buf_ptr);
     } else {
-      ast_error (s, start, "unexpected token");
+      ast_error (s, start, "unexpected token at start of statement");
       return NULL; /* caller syncs */
     }
     ast_expect_semi (s);
@@ -31105,7 +31109,7 @@ static void ast_sem_check_expr (ASTSemState *st, ASTSemScope *scope, cJSON *expr
       const char *pname = cJSON_GetStringValue (cJSON_GetObjectItemCaseSensitive (param, "name"));
       if (pname) ast_sem_add_var (&fn_scope, pname, 1, "input", fn_nr);
       /* Check default value expressions */
-      cJSON *def_val = cJSON_GetObjectItemCaseSensitive (param, "default");
+      cJSON *def_val = cJSON_GetObjectItemCaseSensitive (param, "expression");
       if (def_val) ast_sem_check_expr (st, &fn_scope, def_val);
     }
 
@@ -31398,7 +31402,7 @@ static void ast_sem_check_stmt (ASTSemState *st, ASTSemScope *scope, cJSON *stmt
       const char *pname = cJSON_GetStringValue (cJSON_GetObjectItemCaseSensitive (param, "name"));
       if (pname) ast_sem_add_var (&fn_scope, pname, 1, "input", fn_nr);
       /* Check default value expressions */
-      cJSON *def_val = cJSON_GetObjectItemCaseSensitive (param, "default");
+      cJSON *def_val = cJSON_GetObjectItemCaseSensitive (param, "expression");
       if (def_val) ast_sem_check_expr (st, &fn_scope, def_val);
     }
 
@@ -31503,32 +31507,37 @@ cJSON *JS_ASTTree (const char *source, size_t len, const char *filename) {
     return NULL;
   }
 
-  /* Run semantic pass */
+  /* Run semantic pass - only if parsing succeeded without errors */
-  cJSON *sem_errors = NULL;
+  if (!s.has_error) {
-  cJSON *scopes = NULL;
+    cJSON *sem_errors = NULL;
-  cJSON *intrinsics = NULL;
+    cJSON *scopes = NULL;
-  ast_semantic_check (ast, &sem_errors, &scopes, &intrinsics);
+    cJSON *intrinsics = NULL;
+    ast_semantic_check (ast, &sem_errors, &scopes, &intrinsics);
 
-  /* Attach scopes and intrinsics to AST */
+    /* Attach scopes and intrinsics to AST */
-  if (scopes) cJSON_AddItemToObject (ast, "scopes", scopes);
+    if (scopes) cJSON_AddItemToObject (ast, "scopes", scopes);
-  if (intrinsics) cJSON_AddItemToObject (ast, "intrinsics", intrinsics);
+    if (intrinsics) cJSON_AddItemToObject (ast, "intrinsics", intrinsics);
 
-  /* Merge parse errors and semantic errors */
+    if (sem_errors) {
-  if (s.errors && sem_errors) {
+      cJSON_AddItemToObject (ast, "errors", sem_errors);
-    /* Append semantic errors to parse errors */
+    }
-    cJSON *err;
+  }
-    cJSON *next;
+
-    for (err = sem_errors->child; err; err = next) {
+  if (s.errors) {
-      next = err->next;
+    cJSON *existing = cJSON_GetObjectItemCaseSensitive (ast, "errors");
-      cJSON_DetachItemViaPointer (sem_errors, err);
+    if (existing) {
-      cJSON_AddItemToArray (s.errors, err);
+      /* Append parse errors to existing semantic errors */
+      cJSON *err;
+      cJSON *next;
+      for (err = s.errors->child; err; err = next) {
+        next = err->next;
+        cJSON_DetachItemViaPointer (s.errors, err);
+        cJSON_AddItemToArray (existing, err);
+      }
+      cJSON_Delete (s.errors);
+    } else {
+      cJSON_AddItemToObject (ast, "errors", s.errors);
     }
-    cJSON_Delete (sem_errors);
-    cJSON_AddItemToObject (ast, "errors", s.errors);
-  } else if (s.errors) {
-    cJSON_AddItemToObject (ast, "errors", s.errors);
-  } else if (sem_errors) {
-    cJSON_AddItemToObject (ast, "errors", sem_errors);
   }
 
   return ast;
@@ -32829,6 +32838,28 @@ static int mach_compile_expr(MachCompState *cs, cJSON *node, int dest) {
     /* Scan scope record for var/def declarations */
     mach_scan_scope(&child);
 
+    /* Emit default parameter initialization */
+    for (int i = 0; i < nparams; i++) {
+      cJSON *p = cJSON_GetArrayItem(params, i);
+      cJSON *default_expr = cJSON_GetObjectItemCaseSensitive(p, "expression");
+      if (default_expr) {
+        int slot = 1 + i; /* param slots start at 1 (slot 0 = this) */
+        /* If param is null, skip the JMP and fall into default code */
+        mach_emit(&child, MACH_AsBx(MACH_JMPNULL, slot, 1));
+        /* If param is NOT null, jump past the default code */
+        int jmp_pc = mach_current_pc(&child);
+        mach_emit(&child, MACH_sJ(MACH_JMP, 0)); /* placeholder */
+
+        int save = child.freereg;
+        mach_compile_expr(&child, default_expr, slot);
+        child.freereg = save;
+
+        /* Patch JMP offset */
+        int offset = mach_current_pc(&child) - (jmp_pc + 1);
+        child.code[jmp_pc] = MACH_sJ(MACH_JMP, offset);
+      }
+    }
+
     /* Compile body */
     cJSON *body = cJSON_GetObjectItemCaseSensitive(node, "body");
     if (!body) body = node; /* statements may be directly on the function node */
@@ -35922,13 +35953,11 @@ static void mach_gen_statement (MachGenState *s, cJSON *stmt) {
 
   if (strcmp (kind, "break") == 0) {
     if (s->loop_break) mach_gen_emit_jump (s, s->loop_break);
-    else mach_gen_error (s, stmt, "'break' used outside of loop or switch");
     return;
   }
 
   if (strcmp (kind, "continue") == 0) {
     if (s->loop_continue) mach_gen_emit_jump (s, s->loop_continue);
-    else mach_gen_error (s, stmt, "'continue' used outside of loop");
     return;
   }
 
@@ -36070,6 +36099,24 @@ static cJSON *mach_gen_function (MachGenState *parent, cJSON *func_node) {
   s.next_temp_slot = 1 + s.nr_args + s.nr_local_slots;
   if (s.next_temp_slot > s.max_slot) s.max_slot = s.next_temp_slot;
 
+  /* Emit default parameter initialization */
+  {
+    int ps = 1;
+    cJSON *pp;
+    cJSON_ArrayForEach(pp, params) {
+      cJSON *default_expr = cJSON_GetObjectItemCaseSensitive(pp, "expression");
+      if (default_expr) {
+        char *end_label = mach_gen_label(&s, "default_end");
+        mach_gen_emit_jump_cond(&s, "jump_not_null", ps, end_label);
+        int default_slot = mach_gen_expr(&s, default_expr, -1);
+        mach_gen_emit_2(&s, "move", ps, default_slot);
+        mach_gen_emit_label(&s, end_label);
+        sys_free(end_label);
+      }
+      ps++;
+    }
+  }
+
   /* Pre-load intrinsics (global names) */
   mach_gen_load_intrinsics (&s, cJSON_GetObjectItemCaseSensitive (func_node, "intrinsics"));