refactor(c): modify macro declaration in C.g4 #24

Refactor the macro declaration in C.g4 to improve readability and maintainability. The `defineMacro` rule is now split into three separate rules: `macroAssignDeclaration`, `macroAliasDeclaration`, and `macroStructureDeclaration`. The `macroStatementDeclaration` rule now accepts `macroFunctionExpression` as an optional argument.

Author: phodal

Diff for: chapi-ast-c/src/main/antlr/C.g4

@@ -496,15 +496,20 @@ macroStatement
 //    : include (StringLiteral | Identifier | ('<' includeIdentifier '>' ))             #includeDeclaration
 //    | ('ifdef' | 'ifndef' | 'if') Identifier statement* ('#' 'else' statement*)? '#' 'endif'
 //                                                                                      #ifdefDeclaration
-//    | 'define' Identifier expressionStatement?                                        #macroAssignDeclaration
-//    | 'define' Identifier postixCall Identifier postixCall                            #macroAliasDeclaration
-//    | 'define' Identifier structOrUnionSpecifier                                      #macroStructureDeclaration
+//    | 'define' Identifier defineMacro                                                 #defineDeclaration
 ////    | macroKeywords (assignmentExpression)*
 ////                ('#' macroKeywords)? identifierList?                                  #macroDefineDeclaration
 //    | '#'? Identifier                                                                 #macroCastDeclaration
-//    | macroKeywords assignmentExpression?                                          #macroStatementDeclaration
+//    | macroKeywords macroFunctionExpression?                                          #macroStatementDeclaration
 //    ;
 //
+//defineMacro
+//    : expressionStatement?                                        #macroAssignDeclaration
+//    | postixCall Identifier postixCall                            #macroAliasDeclaration
+//    | structOrUnionSpecifier                                      #macroStructureDeclaration
+//    ;
+//
+//
 //macroFunctionExpression
 //    : Identifier
 //    | Identifier '(' ( parameterTypeList| (macroType (',' macroType)*) ) ')'
@@ -516,7 +521,6 @@ macroStatement
 //    | expressionStatement
 //    ;
 //
-//
 //macroKeywords
 //    :  'if' | 'undef' | 'else' | 'pragma' | 'endif' | 'ifdef' | 'ifndef' | 'elif' | 'define' | 'ifndef' | 'error'
 //    ;