added parsing of if statements

src/ast/expressions/if_then_else.cpp

@@ -0,0 +1,23 @@
+
+#include "if_then_else.hpp"
+
+#include <sstream>
+
+namespace ast {
+    if_then_else::if_then_else(token::token token)
+        : token(std::move(token)),
+          consequence(nullptr),
+          alternative(nullptr) {};
+
+    std::string if_then_else::token_literal() const {
+        return token.literal;
+    };
+
+    std::string if_then_else::str() const {
+        std::stringstream ss;
+        ss << "if " << condition->str() << consequence->str();
+        if (alternative != nullptr)
+            ss << "else" << alternative->str();
+        return ss.str();
+    };
+} // namespace ast

src/ast/expressions/if_then_else.hpp

@@ -0,0 +1,19 @@
+#pragma once
+
+#include "ast/ast.hpp"
+#include "ast/statements/block.hpp"
+#include "token/token.hpp"
+
+#include <string>
+
+namespace ast {
+    struct if_then_else : expression {
+        if_then_else(token::token);
+        token::token token;
+        ast::expression* condition;
+        ast::block_stmt *consequence, *alternative;
+
+        std::string token_literal() const override;
+        std::string str() const override;
+    };
+} // namespace ast

src/ast/statements/block.cpp

@@ -0,0 +1,25 @@
+#include "block.hpp"
+
+#include <sstream>
+
+namespace ast {
+    block_stmt::block_stmt(token::token token): token(std::move(token)) {}
+
+    std::string block_stmt::token_literal() const {
+        return token.literal;
+    }
+
+    block_stmt::~block_stmt() {
+        for (const auto& stmt : statements)
+            delete stmt;
+    };
+
+    std::string block_stmt::str() const {
+        std::stringstream ss;
+        ss << "{";
+        for (const auto& stmt : statements)
+            ss << stmt->str();
+        ss << "}";
+        return ss.str();
+    };
+} // namespace ast

src/ast/statements/block.hpp

@@ -0,0 +1,20 @@
+#pragma once
+
+#include "ast/ast.hpp"
+#include "token/token.hpp"
+
+#include <vector>
+
+namespace ast {
+    struct block_stmt : statement {
+        block_stmt(token::token token);
+
+        token::token token;
+        std::vector<ast::statement*> statements;
+
+        std::string token_literal() const override;
+        std::string str() const override;
+
+        ~block_stmt();
+    };
+} // namespace ast