better parse errors

tests/decl_restrictions.ce

@@ -0,0 +1,165 @@
+// Declaration restriction tests
+// Run: ./cell tests/decl_restrictions.ce
+
+var tokenize = use("tokenize")
+var parse = use("parse")
+
+var passed = 0
+var failed = 0
+var error_names = []
+var error_reasons = []
+var fail_msg = ""
+
+var _i = 0
+for (_i = 0; _i < 20; _i++) {
+  error_names[] = null
+  error_reasons[] = null
+}
+
+var fail = function(msg) {
+  fail_msg = msg
+  disrupt
+}
+
+var run = function(name, fn) {
+  fail_msg = ""
+  fn()
+  passed = passed + 1
+} disruption {
+  error_names[failed] = name
+  error_reasons[failed] = fail_msg == "" ? "disruption" : fail_msg
+  failed = failed + 1
+}
+
+var parse_snippet = function(src) {
+  var result = tokenize(src, "<test>")
+  var ast = parse(result.tokens, src, "<test>", tokenize)
+  return ast
+}
+
+var has_error = function(ast, substring) {
+  if (ast.errors == null) return false
+  var i = 0
+  while (i < length(ast.errors)) {
+    if (search(ast.errors[i].message, substring) != null) return true
+    i = i + 1
+  }
+  return false
+}
+
+var has_no_errors = function(ast) {
+  return ast.errors == null || length(ast.errors) == 0
+}
+
+// === BARE BLOCK ===
+
+run("bare block rejected", function() {
+  var ast = parse_snippet("{ var x = 1 }")
+  if (!has_error(ast, "bare block")) fail("expected 'bare block' error, got: " + text(ast.errors))
+})
+
+// === VAR IN IF (braces) ===
+
+run("var in if braces", function() {
+  var ast = parse_snippet("if (true) { var x = 1 }")
+  if (!has_error(ast, "not inside 'if'")) fail("expected 'not inside if' error, got: " + text(ast.errors))
+})
+
+// === VAR IN IF (no braces) ===
+
+run("var in if no braces", function() {
+  var ast = parse_snippet("if (true) var x = 1")
+  if (!has_error(ast, "not inside 'if'")) fail("expected 'not inside if' error, got: " + text(ast.errors))
+})
+
+// === VAR IN WHILE ===
+
+run("var in while", function() {
+  var ast = parse_snippet("while (true) { var x = 1; break }")
+  if (!has_error(ast, "not inside 'while'")) fail("expected 'not inside while' error, got: " + text(ast.errors))
+})
+
+// === VAR IN FOR INIT ===
+
+run("var in for init", function() {
+  var ast = parse_snippet("for (var i = 0; i < 1; i++) {}")
+  if (!has_error(ast, "for initializer")) fail("expected 'for initializer' error, got: " + text(ast.errors))
+})
+
+// === VAR IN FOR BODY ===
+
+run("var in for body", function() {
+  var ast = parse_snippet("var i = 0; for (i = 0; i < 1; i++) { var x = 1 }")
+  if (!has_error(ast, "not inside 'for'")) fail("expected 'not inside for' error, got: " + text(ast.errors))
+})
+
+// === VAR IN DO ===
+
+run("var in do", function() {
+  var ast = parse_snippet("do { var x = 1; break } while (true)")
+  if (!has_error(ast, "not inside 'do'")) fail("expected 'not inside do' error, got: " + text(ast.errors))
+})
+
+// === DEF IN IF ===
+
+run("def in if", function() {
+  var ast = parse_snippet("if (true) { def x = 1 }")
+  if (!has_error(ast, "not inside 'if'")) fail("expected 'not inside if' error, got: " + text(ast.errors))
+})
+
+// === UNINITIALIZED VAR ===
+
+run("uninitialized var", function() {
+  var ast = parse_snippet("var x")
+  if (!has_error(ast, "must be initialized")) fail("expected 'must be initialized' error, got: " + text(ast.errors))
+})
+
+// === NESTED: VAR IN IF INSIDE WHILE ===
+
+run("nested var in if inside while", function() {
+  var ast = parse_snippet("while (true) { if (true) { var x = 1 }; break }")
+  if (!has_error(ast, "not inside 'if'")) fail("expected 'not inside if' error, got: " + text(ast.errors))
+})
+
+// === VALID: NESTED FUNCTION ===
+
+run("valid nested fn in control flow", function() {
+  var ast = parse_snippet("if (true) { var fn = function() { var x = 1; return x } }")
+  // The var inside the function is fine; only the var fn = ... inside if should error
+  if (!has_error(ast, "not inside 'if'")) fail("expected error for var fn inside if")
+  // But there should NOT be an error about var x inside the function body
+  var i = 0
+  var bad = false
+  if (ast.errors != null) {
+    while (i < length(ast.errors)) {
+      if (search(ast.errors[i].message, "var x") != null) bad = true
+      i = i + 1
+    }
+  }
+  if (bad) fail("should not error on var inside nested function")
+})
+
+// === VALID: NORMAL VAR ===
+
+run("valid normal var", function() {
+  var ast = parse_snippet("var x = 1")
+  if (!has_no_errors(ast)) fail("expected no errors, got: " + text(ast.errors))
+})
+
+// === VALID: VAR IN FUNCTION BODY ===
+
+run("valid var in function body", function() {
+  var ast = parse_snippet("var fn = function() { var x = 1; return x }")
+  if (!has_no_errors(ast)) fail("expected no errors, got: " + text(ast.errors))
+})
+
+// === SUMMARY ===
+
+print(text(passed) + " passed, " + text(failed) + " failed out of " + text(passed + failed))
+var _j = 0
+if (failed > 0) {
+  print("")
+  for (_j = 0; _j < failed; _j++) {
+    print("  FAIL " + error_names[_j] + ": " + error_reasons[_j])
+  }
+}