parser.h

#ifndef PARSER_H
#define PARSER_H

#include <vector>
#include <initializer_list>
#include "token.h"
#include "ast.h"

// Parser turns a flat list of tokens into an abstract syntax tree. It handles
// declarations, statements and expressions for FunLang.
class Parser {
public:
    explicit Parser(const std::vector<Token>& tokens);
    std::vector<StmtPtr> parseProgram();

private:
    std::vector<Token> tks;
    size_t cur;

    bool isAtEnd() const;
    const Token& peek() const;
    const Token& prev() const;
    const Token& advance();

    bool check(TokenType t) const;
    bool match(TokenType t);
    bool matchAny(std::initializer_list<TokenType> types);
    const Token& consume(TokenType t, const std::string& msg);

    bool isTypeToken(const Token& tk) const;

    // top‑level declarations or statements
    StmtPtr declOrStmt();
    StmtPtr funcDecl();
    StmtPtr varDecl();
    StmtPtr printStmt();
    StmtPtr assignOrExprStmt();

    // new statements
    StmtPtr whileStmt();
    StmtPtr forStmt();
    StmtPtr ifStmt();
    StmtPtr parseForAssignOrEmpty(); // parse IDENT '=' expr or empty

    // expressions
    ExprPtr expression();
    ExprPtr logicOr();
    ExprPtr logicAnd();
    ExprPtr equality();
    ExprPtr comparison();
    ExprPtr term();
    ExprPtr factor();
    ExprPtr unary();
    ExprPtr call();
    ExprPtr primary();
};

#endif