parser: Merge consecutive "Unexpected tokens" errors

Fixes #24

blueprintcompiler/errors.py

@@ -85,6 +85,11 @@ at {filename} line {line_num} column {col_num}:
         print()
 
 
+class UnexpectedTokenError(CompileError):
+    def __init__(self, start, end):
+        super().__init__("Unexpected tokens", start, end)
+
+
 @dataclass
 class CodeAction:
     title: str

blueprintcompiler/parse_tree.py

@@ -25,7 +25,7 @@ from collections import defaultdict
 from enum import Enum
 
 from .ast import AstNode
-from .errors import assert_true, CompilerBugError, CompileError
+from .errors import assert_true, CompilerBugError, CompileError, UnexpectedTokenError
 from .tokenizer import Token, TokenType
 
 
@@ -184,6 +184,22 @@ class ParseContext:
         token = self.tokens[self.index]
         return token
 
+    def skip_unexpected_token(self):
+        """ Skips a token and logs an "unexpected token" error. """
+
+        self.skip()
+        start = self.tokens[self.index].start
+        self.next_token()
+        self.skip()
+        end = self.tokens[self.index - 1].end
+
+        if (len(self.errors)
+                and isinstance((err := self.errors[-1]), UnexpectedTokenError)
+                and err.end == start):
+            err.end = end
+        else:
+            self.errors.append(UnexpectedTokenError(start, end))
+
     def is_eof(self) -> Token:
         return self.index >= len(self.tokens) or self.peek_token().type == TokenType.EOF
 
@@ -330,8 +346,7 @@ class Until(ParseNode):
         while not self.delimiter.parse(ctx).succeeded():
             try:
                 if not self.child.parse(ctx).matched():
-                    token = ctx.next_token()
+                    ctx.skip_unexpected_token()
-                    ctx.errors.append(CompileError("Unexpected token", token.start, token.end))
             except CompileError as e:
                 ctx.errors.append(e)
                 ctx.next_token()

tests/sample_errors/consecutive_unexpected_tokens.blp

@@ -0,0 +1,7 @@
+using Gtk 4.0;
+
+Button {
+  visible: false;
+  not actually blueprint code;
+  Label {}
+}

tests/sample_errors/consecutive_unexpected_tokens.err

@@ -0,0 +1 @@
+5,3,31,Unexpected tokens

tests/test_samples.py

@@ -71,9 +71,9 @@ class TestSamples(unittest.TestCase):
                 raise MultipleErrors(ast.errors)
         except PrintableError as e:
             def error_str(error):
-                line, col = utils.idx_to_pos(error.start, blueprint)
+                line, col = utils.idx_to_pos(error.start + 1, blueprint)
                 len = error.end - error.start
-                return ",".join([str(line + 1), str(col + 1), str(len), error.message])
+                return ",".join([str(line + 1), str(col), str(len), error.message])
 
             if isinstance(e, CompileError):
                 actual = error_str(e)
@@ -143,6 +143,7 @@ class TestSamples(unittest.TestCase):
         self.assert_sample_error("a11y_prop_type")
         self.assert_sample_error("class_assign")
         self.assert_sample_error("class_dne")
+        self.assert_sample_error("consecutive_unexpected_tokens")
         self.assert_sample_error("duplicate_obj_id")
         self.assert_sample_error("enum_member_dne")
         self.assert_sample_error("filters_in_non_file_filter")