added the parsing of expression statements

src/ast/statements/expression.cpp

@@ -0,0 +1,16 @@
+#include "expression.hpp"
+
+namespace ast {
+
+    expression_stmt::expression_stmt(token::token token)
+        : token(std::move(token)),
+          expression(nullptr) {}
+
+    std::string expression_stmt::token_literal() const {
+        return token.literal;
+    }
+
+    expression_stmt::~expression_stmt() {
+        delete expression;
+    }
+} // namespace ast

src/ast/statements/expression.hpp

@@ -0,0 +1,15 @@
+#include "ast/ast.hpp"
+#include "token/token.hpp"
+
+namespace ast {
+    struct expression_stmt : statement {
+        expression_stmt(token::token token);
+
+        token::token token;
+        ast::expression* expression;
+
+        std::string token_literal() const override;
+
+        ~expression_stmt();
+    };
+} // namespace ast