feat(wheel_parser): add expression declaration parser

Author: Reim-developer

wheel_parser/include/wheel_parser/functions/expression_declaration.hxx

@@ -0,0 +1,46 @@
+
+#if !defined (PARSE_EXPRESSION_DECLARATION_HXX)
+#define PARSE_EXPRESSION_DECLARATION_HXX
+#include "wheel_parser/config.hxx"
+#include "contracts_declaration.hxx"
+#include "wheel_parser/ast/nodes.hxx"
+#include <wheel_lexer/kind.hxx>
+#include "wheel_parser/parser_utils.hxx"
+
+WHEEL_PARSER_FUNCTIONS_BEGIN_NAMESPACE
+    using wheel_parser::ast::ExpressionNode;
+    using wheel_parser::ast::LiteralExpression;
+    using wheel_parser::ast::IdentifierExpression;
+    using wheel_lexer::TokenKind;
+
+    PARSE_BEGIN(parse_expression_declaration, ExpressionNode)
+        using Kind = TokenKind;
+        auto current_token = contract.state.current_token;
+        auto arena = &contract.arena;
+        auto interner = &contract.interner;
+
+        switch (current_token.kind) {
+            case TokenKind::INT_LITERAL:
+            case TokenKind::FLOAT_LITERAL:
+            case TokenKind::STRING_LITERAL:
+            case TokenKind::RAW_STRING_LITERAL:
+                return arena->allocate<LiteralExpression>(
+                    copy_token(*arena, current_token)
+                );
+
+            case TokenKind::IDENT:
+                return arena->allocate<IdentifierExpression>(
+                    copy_token(*arena, current_token),
+                    interner->intern(current_token.str)
+                );
+
+            default:
+                return nullptr;
+        }
+
+    PARSE_END
+
+
+WHEEL_PARSER_FUNCTIONS_END_NAMESPACE
+
+#endif