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# parser.py
import ply.yacc as yacc
from lexer import tokens
# --- AST node types ---
class Label:
def __init__(self, name):
self.name = name
def __repr__(self):
return f"Label({self.name!r})"
class Instr:
def __init__(self, op, args):
self.op = op # "mov", "add", "jmp"
self.args = args # list of operands
def __repr__(self):
return f"Instr({self.op!r}, {self.args!r})"
# --- Grammar ---
def p_program(p):
"""program : lines"""
p[0] = p[1]
def p_lines_multi(p):
"""lines : lines line"""
# p[1] is the list so far, p[2] is a single line (Label or Instr)
p[0] = p[1]
if p[2] is not None:
p[0].append(p[2])
def p_lines_single(p):
"""lines : line"""
# start list with the single line (unless it's None; but we never produce None here)
p[0] = [p[1]] if p[1] is not None else []
def p_line(p):
"""line : label
| instruction"""
p[0] = p[1]
def p_label(p):
"""label : IDENT COLON"""
p[0] = Label(p[1])
def p_instruction_mov(p):
"""instruction : MOV REGISTER COMMA NUMBER"""
# mov A, #123
p[0] = Instr("mov", [p[2], p[4]])
def p_instruction_add(p):
"""instruction : ADD REGISTER COMMA REGISTER"""
# add B, A
p[0] = Instr("add", [p[2], p[4]])
def p_instruction_jmp(p):
"""instruction : JMP IDENT"""
# jmp label
p[0] = Instr("jmp", [p[2]])
def p_error(p):
if p is None:
raise SyntaxError("Syntax error at EOF")
else:
raise SyntaxError(f"Syntax error at {p.value!r} (type {p.type})")
parser = yacc.yacc()
|
