Add support for guarded branches, closes #258

CHANGELOG.md

@@ -9,6 +9,7 @@
  - Added support for properties in `gd2py`
  - Added support for `get():` property syntax
  - Added support for multiline arrays and dictionaries in `match` statement branches
+ - Added support for guarded `match` branches
 
 ### Changed
  - Fixed support for `breakpoint` statement in formatter

gdtoolkit/formatter/function_statement.py

@@ -7,6 +7,7 @@
 from .context import Context, ExpressionContext
 from .types import Outcome, FormattedLines
 from .expression import format_expression
+from .expression_to_str import expression_to_str
 from .block import format_block, reconstruct_blank_lines_in_range
 from .statement_utils import format_simple_statement
 from .var_statement import format_var_statement
@@ -32,6 +33,7 @@ def format_func_statement(statement: Tree, context: Context) -> Outcome:
         "annotation": format_standalone_annotation,
         # fake statements:
         "match_branch": _format_match_branch,
+        "guarded_match_branch": _format_guarded_match_branch,
     }  # type: Dict[str, Callable]
     return handlers[statement.data](statement, context)
 
@@ -106,6 +108,15 @@ def _format_match_branch(statement: Tree, context: Context) -> Outcome:
     return _format_branch(prefix, suffix, expr_position, statement, context)
 
 
+def _format_guarded_match_branch(statement: Tree, context: Context) -> Outcome:
+    # TODO: fold pattern as well
+    pattern_str = expression_to_str(statement.children[0].children[0])
+    prefix = f"{pattern_str} when "
+    suffix = ":"
+    expr_position = 1
+    return _format_branch(prefix, suffix, expr_position, statement, context)
+
+
 def _format_branch(
     prefix: str,
     suffix: str,

gdtoolkit/parser/gdscript.lark

@@ -123,7 +123,8 @@ for_stmt: "for" NAME "in" expr ":" _func_suite
 for_stmt_typed: "for" _for_iterator_var_typed "in" expr ":" _func_suite
 match_stmt: "match" expr ":" _match_body
 _match_body: _NL _INDENT match_branch+ _DEDENT
-match_branch: pattern ":" _func_suite
+?match_branch: pattern ":" _func_suite
+             | pattern "when" expr ":" _func_suite -> guarded_match_branch
 
 pattern: list_pattern
 ?list_pattern: test_pattern ("," test_pattern)*

tests/formatter/input-output-pairs/multiline_match_statements.in.gd

@@ -37,6 +37,8 @@ class X:
 				pass
 			[_,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1]:
 				pass
+			[_,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1] when [1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1]:
+				pass
 			{'aaaaa', 'bbbbbbbbbbbbbbbbbbbbb': 1111, 'ccccccccccccccccccccc': 1111, 'ddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddd': 1111}:
 				pass
 			[1,2,]:

tests/formatter/input-output-pairs/multiline_match_statements.out.gd

@@ -291,6 +291,50 @@ class X:
 				1
 			]:
 				pass
+			[_, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1] when [
+				1,
+				1,
+				1,
+				1,
+				1,
+				1,
+				1,
+				1,
+				1,
+				1,
+				1,
+				1,
+				1,
+				1,
+				1,
+				1,
+				1,
+				1,
+				1,
+				1,
+				1,
+				1,
+				1,
+				1,
+				1,
+				1,
+				1,
+				1,
+				1,
+				1,
+				1,
+				1,
+				1,
+				1,
+				1,
+				1,
+				1,
+				1,
+				1,
+				1,
+				1
+			]:
+				pass
 			{
 				"aaaaa",
 				"bbbbbbbbbbbbbbbbbbbbb": 1111,

tests/formatter/input-output-pairs/simple_match_statements.in.gd

@@ -45,6 +45,12 @@ class X:
 				pass
 			1 if 1 else 2:
 				pass
+			2 when true:
+				pass
+			2 when 1 == 1:
+				pass
+			2 when 1.0 as int:
+				pass
 			_:
 				pass
 		match Vector3(1,1,1):

tests/formatter/input-output-pairs/simple_match_statements.out.gd

@@ -45,6 +45,12 @@ class X:
 				pass
 			1 if 1 else 2:
 				pass
+			2 when true:
+				pass
+			2 when 1 == 1:
+				pass
+			2 when 1.0 as int:
+				pass
 			_:
 				pass
 		match Vector3(1, 1, 1):

tests/valid-gd-scripts/match.gd

@@ -3,6 +3,14 @@ func foo(x):
 	match x:
 		1:
 			pass
+		5 when true:
+			pass
+		6 when 1 + 2 > 0:
+			pass
+		7 when y.aaa.bb == 0:
+			pass
+		8 when 1.0 as int:
+			pass
 		# TODO: remove support for
 		# y.aaa:
 		# 	pass