very basic parser of let statements

src/ast/ast.cpp

@@ -0,0 +1,9 @@
+#include "ast.hpp"
+
+namespace ast {
+    std::string program ::token_literal() const {
+        if (statements.size() > 0)
+            return statements[0]->token_literal();
+        return "";
+    }
+} // namespace ast

src/ast/ast.hpp

@@ -0,0 +1,29 @@
+#pragma once
+
+#include <string>
+#include <vector>
+
+namespace ast {
+    struct node {
+        virtual std::string token_literal() const = 0;
+        virtual ~node() = default;
+    };
+
+    struct statement : node {
+        virtual std::string token_literal() const override = 0;
+    };
+
+    struct expression : node {
+        virtual std::string token_literal() const override = 0;
+    };
+
+    struct program : public node {
+        std::vector<statement*> statements;
+        std::string token_literal() const override;
+
+        ~program() {
+            for (const auto& ref : statements)
+                delete ref;
+        };
+    };
+} // namespace ast

src/ast/expressions/identifier.cpp

@@ -0,0 +1,11 @@
+#include "identifier.hpp"
+
+namespace ast {
+    identifier::identifier(token::token token, std::string value)
+        : token(std::move(token)),
+          value(std::move(value)) {}
+
+    std::string identifier::token_literal() const {
+        return token.literal;
+    }
+} // namespace ast

src/ast/expressions/identifier.hpp

@@ -0,0 +1,16 @@
+#pragma once
+
+#include "ast/ast.hpp"
+#include "token/token.hpp"
+
+#include <string>
+
+namespace ast {
+    struct identifier : expression {
+        identifier(token::token token, std::string value);
+        token::token token;
+        std::string value;
+
+        std::string token_literal() const override;
+    };
+} // namespace ast

src/ast/statements/let.cpp

@@ -0,0 +1,17 @@
+#include "let.hpp"
+
+namespace ast {
+    let::let(token::token token)
+        : token(std::move(token)),
+          name(nullptr),
+          value(nullptr) {}
+
+    std::string let::token_literal() const {
+        return token.literal;
+    }
+
+    let::~let() {
+        delete name;
+        delete value;
+    };
+} // namespace ast

src/ast/statements/let.hpp

@@ -0,0 +1,19 @@
+#pragma once
+
+#include "ast/ast.hpp"
+#include "ast/expressions/identifier.hpp"
+#include "token/token.hpp"
+
+namespace ast {
+    struct let : statement {
+        let(token::token token);
+
+        token::token token;
+        identifier* name;
+        expression* value;
+
+        std::string token_literal() const override;
+
+        ~let();
+    };
+} // namespace ast