parser

1 files changed, 171 insertions, 0 deletions

diff --git a/src/parser/parser.cpp b/src/parser/parser.cpp
new file mode 100644
index 0000000..9eb94a3
--- /dev/null
+++ b/src/parser/parser.cpp
@@ -0,0 +1,171 @@
+#include <iostream>
+
+#include "parser/parser.h"
+
+Parser::Parser(const std::vector<Token>& tokens) : tokens_(tokens), position_(0) {}
+
+std::unique_ptr<Program> Parser::parse() {
+    auto program = std::make_unique<Program>();
+
+    while (peek().type != TokenType::END_OF_FILE) {
+        try {
+            auto statement = parseStatement();
+            program->declarations.push_back(std::move(statement));
+            
+            if (peek().type == TokenType::SEMICOLON) {
+                advance();
+            }
+        }
+
+        catch (const std::exception& e) {
+            std::cerr << " Parser error: " << e.what() << std::endl;
+            break;
+        }
+    } 
+    
+    return program;
+}
+
+std::unique_ptr<ASTNode> Parser::parseStatement() {
+    switch(peek().type) {
+        case TokenType::INT:
+        case TokenType::STRING:
+        {
+            return parseDeclaration();
+            break;
+        }
+
+        default:
+        {
+            error("Unexpected statement");
+            return nullptr;
+        }
+    }
+}
+
+std::unique_ptr<ASTNode> Parser::parseExpression() {
+    return parseAddSub(); 
+}
+
+std::unique_ptr<ASTNode> Parser::parseDeclaration() {
+    std::string type;
+
+    switch(peek().type) {
+        case TokenType::INT:
+        {
+            type = "int";
+            break;
+        }
+
+        case TokenType::STRING:
+        {
+            type = "string";
+            break;
+        }
+
+        default:
+        {
+            error("Unexpected declaration: Invalid type");
+            return nullptr;
+        }
+    }
+    
+    advance();
+    std::string name = peek().value;
+    advance();
+    if (peek().type == TokenType::ASSIGN) {
+        advance();
+        auto value = parseExpression();
+        return std::make_unique<Declaration>(type, name, std::move(value));
+    } 
+
+    else if (peek().type == TokenType::SEMICOLON) {
+        return std::make_unique<Declaration>(type, name); 
+    }
+
+    else {
+        error("Invalid declaration");
+        return nullptr;
+    }
+}
+
+std::unique_ptr<ASTNode> Parser::parseAssignment() {
+    std::string name = peek().value;
+    advance();
+    advance(); // consume =
+    auto value = parseExpression();
+    return std::make_unique<Assignment>(name, std::move(value));
+}
+
+std::unique_ptr<ASTNode> Parser::parseAddSub() {
+    auto left = parseMulDiv();
+
+    while (peek().type == TokenType::PLUS || peek().type == TokenType::MINUS) {
+        std::string op = peek().value;
+        advance();
+        auto right = parseMulDiv();
+        left = std::make_unique<BinaryOp>(std::move(left), op, std::move(right));
+    }
+
+    return left;
+}
+
+std::unique_ptr<ASTNode> Parser::parseMulDiv() {
+    auto left = parsePrimary();
+    
+    while (peek().type == TokenType::MULTIPLY || peek().type == TokenType::DIVIDE) {
+        std::string op = peek().value;
+        advance();
+        auto right = parsePrimary();
+        left = std::make_unique<BinaryOp>(std::move(left), op, std::move(right));
+    } 
+
+    return left;
+}
+
+std::unique_ptr<ASTNode> Parser::parsePrimary() {
+    switch(peek().type) {
+        case TokenType::NUMBER:
+        {
+            double value = std::stod(peek().value);
+            advance();
+            return std::make_unique<NumberLiteral>(value);
+        }
+
+        case TokenType::IDENTIFIER:
+        {
+            std::string name = peek().value;
+            advance();
+            return std::make_unique<Identifier>(name);
+        }
+
+        case TokenType::STRING:
+        {
+            std::string value = peek().value;
+            advance();
+            return std::make_unique<StringLiteral>(value);
+        }
+
+        default:
+        {
+            error("Unknown keyword");
+            return nullptr;
+        }
+    }
+}
+
+Token Parser::advance() {
+    return tokens_[position_++];
+}
+
+Token Parser::peek() {
+    return tokens_[position_];
+}
+
+bool Parser::isAtEnd() {
+    return position_ >= tokens_.size();
+}
+
+void Parser::error(std::string s) {
+
+}