# parser.py
import ply.yacc as yacc
from lexer import tokens


# AST node types
class Label:
    def __init__(self, name):
        self.name = name


class Instr:
    def __init__(self, op, args):
        self.op = op
        self.args = args


def p_program(p):
    """program : program line
    | line"""
    if len(p) == 2:
        p[0] = [p[1]]
    else:
        p[0] = p[1] + [p[2]]


def p_line(p):
    """line : label
    | instruction
    | empty"""
    p[0] = p[1]


def p_label(p):
    """label : IDENT COLON"""
    p[0] = Label(p[1])


def p_instruction(p):
    """instruction : MOV REGISTER COMMA NUMBER
    | ADD REGISTER COMMA REGISTER
    | JMP IDENT"""
    op = p[1]
    args = p[2:]
    p[0] = Instr(op, args)


def p_empty(p):
    "empty :"
    p[0] = None


def p_error(p):
    raise SyntaxError("Syntax error")


parser = yacc.yacc()