Increase priority of constant rule in grammar (#108)

blark/iec.lark

@@ -36,11 +36,11 @@ _library_element_declaration: data_type_declaration
 IDENTIFIER: /[A-Za-z_][A-Za-z0-9_]*/i
 
 // B.1.2
-constant: time_literal
-        | numeric_literal
-        | string_literal
-        | bit_string_literal
-        | boolean_literal
+constant.1: time_literal
+          | numeric_literal
+          | string_literal
+          | bit_string_literal
+          | boolean_literal
 
 // B.1.2.1
 BIT_STRING: /(1|0)(_?(1|0))*/
@@ -430,7 +430,6 @@ edge_declaration: var1_list ":" _BOOL ( R_EDGE | F_EDGE )
 
 ?var_init_decl: array_var_init_decl
               | structured_var_init_decl
-              | string_var_declaration
               | var1_init_decl
               | fb_decl
 
@@ -499,20 +498,13 @@ location: _AT direct_variable
 
 global_var_list: global_var_name ( "," global_var_name )*
 
-?string_var_declaration: single_byte_string_var_declaration
-                       | double_byte_string_var_declaration
-
-single_byte_string_var_declaration: var1_list ":" single_byte_string_spec
-
 bracketed_expression: "[" expression "]"
 
 string_spec_length: parenthesized_expression
                   | bracketed_expression
 
 single_byte_string_spec: STRING [ string_spec_length ] [ ":=" SINGLE_BYTE_CHARACTER_STRING ]
 
-double_byte_string_var_declaration: var1_list ":" double_byte_string_spec
-
 double_byte_string_spec: WSTRING [ string_spec_length ] [ ":=" DOUBLE_BYTE_CHARACTER_STRING ]
 
 incomplete_located_var_declarations: _VAR [ variable_attributes ] incomplete_located_var_decl* _END_VAR ";"*

blark/tests/test_parsing.py

@@ -1,5 +1,6 @@
 import pathlib
 
+import lark
 import pytest
 
 from ..parse import parse, parse_source_code, summarize
@@ -130,3 +131,31 @@ def test_comment_parsing(code: str, expected_snippets: list[str]):
         result.source_code[token.start_pos: token.end_pos] for token in result.comments
     ]
     assert snippets == expected_snippets
+
+
+def tree_contains_token(tree, token):
+    """
+    Checks whether the given lark tree contains the given token, either as a node
+    or as a leaf.
+    """
+    return any((
+        tree.data == token,
+        token in tree.children,
+        any(tree_contains_token(child, token)
+            for child in tree.children
+            if isinstance(child, lark.Tree))))
+
+
+@pytest.mark.parametrize(
+    "start_rule, code, token_type, token_value",
+    [
+        pytest.param("unary_expression", "TRUE", "RULE", "constant"),
+        pytest.param("unary_expression", "TRUE", "TRUE_VALUE", "TRUE"),
+        pytest.param("unary_expression", "FALSE", "RULE", "constant"),
+        pytest.param("unary_expression", "FALSE", "FALSE_VALUE", "FALSE"),
+    ],
+)
+def test_key_token(start_rule: str, code: str, token_type: str, token_value: str):
+    """Test whether the parse tree contains the key token."""
+    result = conftest.get_grammar(start=start_rule).parse(code)
+    assert tree_contains_token(result, lark.Token(token_type, token_value))

blark/transform.py

@@ -2494,7 +2494,7 @@ def __str__(self) -> str:
     EnumeratedTypeInitialization,
     ArrayTypeInitialization,
     InitializedStructure,
-    _GenericInit,  # StringVariableInitDeclaration, EdgeDeclaration
+    _GenericInit,  # EdgeDeclaration
 ]
 
 
@@ -2568,44 +2568,6 @@ class StructuredVariableInitDeclaration(InitDeclaration):
     meta: Optional[Meta] = meta_field()
 
 
-@dataclass
-@_rule_handler(
-    "single_byte_string_var_declaration",
-    "double_byte_string_var_declaration",
-    comments=True
-)
-class StringVariableInitDeclaration(InitDeclaration):
-    """
-    A declaration of one or more variables using single/double byte strings,
-    with an optinoal initialization value.
-
-    Examples::
-
-        sVar1 : STRING(2_500_000) := 'test1'
-        sVar2, sVar3 : STRING(Param.iLower) := 'test2'
-        sVar4, sVar5 : WSTRING(Param.iLower) := "test3"
-    """
-    variables: List[DeclaredVariable]
-    spec: StringTypeSpecification
-    value: Optional[lark.Token]
-    init: _GenericInit
-    meta: Optional[Meta] = meta_field()
-
-    @staticmethod
-    def from_lark(variables: List[DeclaredVariable], string_info: StringTypeInitialization):
-        return StringVariableInitDeclaration(
-            variables=variables,
-            spec=string_info.spec,
-            value=string_info.value,
-            init=_GenericInit(
-                base_type_name=str(string_info.spec.base_type_name),
-                full_type_name=str(string_info.spec.full_type_name),
-                value=str(string_info.value),
-                repr=join_if(string_info.spec, " := ", string_info.value),
-            )
-        )
-
-
 @dataclass
 @_rule_handler("edge_declaration", comments=True)
 class EdgeDeclaration(InitDeclaration):
@@ -3294,7 +3256,6 @@ def __str__(self) -> str:
 
 VariableInitDeclaration = Union[
     ArrayVariableInitDeclaration,
-    StringVariableInitDeclaration,
     VariableOneInitDeclaration,
     FunctionBlockDeclaration,
     EdgeDeclaration,