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expression_translator.py
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expression_translator.py
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from __future__ import annotations
import json
from dataclasses import dataclass
from typing import Callable, cast
from computer_simulator.isa import Arg, ArgType, Instruction, Opcode
from computer_simulator.translator.errors import InvalidSymbolsError
from computer_simulator.translator.tokenizer import Token
EXPECTED_IDENTIFIER = "Expected identifier"
STATIC_MEMORY_SIZE = 512
DEFAULT_WORD = 0
STRING_ALLOC_SIZE = 32
SERVICE_VAR_ADDR = 1
@dataclass
class Function:
address: int
setq_count: int
@dataclass
class StackValue:
value: int
name: str | None
class Program:
def __init__(self):
# only for strings
self.memory: list[int | Instruction] = [0 for _ in range(STATIC_MEMORY_SIZE)]
self.memory_used: int = 0
self.current_stack: list[StackValue] = []
self.functions: dict[str, int] = {}
self.current_block_setq_count: int = 0
def load(self, value: int) -> None:
self.memory.append(Instruction(Opcode.LD, Arg(value, ArgType.DIRECT)))
# allocates variable on top of stack
def push_var_to_stack(self, name: str | None = None) -> None:
self.memory.append(Instruction(Opcode.PUSH, arg=None, comment=f"Push var {name}"))
self.current_stack.append(StackValue(len(self.memory), name))
def resolve_stack_var(self, name: str) -> None:
self.current_stack.append(StackValue(len(self.memory), name))
def unresolve_stack_var(self, name: str) -> None:
for i in range(len(self.current_stack) - 1, -1, -1):
if self.current_stack[i].name == name:
self.current_stack.pop(i)
return
raise InvalidSymbolsError(got=name, expected="known variable, but got unknown")
def pop_var_from_stack(self, comment: str | None = None) -> None:
self.memory.append(Instruction(Opcode.POP, None, comment))
self.current_stack.pop()
def alloc_string(self, value: str) -> int:
address = self.memory_used
self.memory[self.memory_used] = len(value)
self.memory.append(Instruction(Opcode.LD, Arg(len(value), ArgType.DIRECT)))
self.memory.append(Instruction(Opcode.ST, Arg(self.memory_used, ArgType.ADDRESS)))
self.memory_used += 1
for char in value:
self.memory[self.memory_used] = ord(char)
self.memory.append(Instruction(Opcode.LD, Arg(ord(char), ArgType.DIRECT)))
self.memory.append(Instruction(Opcode.ST, Arg(self.memory_used, ArgType.ADDRESS)))
self.memory_used += 1
return address
def alloc_string_of_size(self, size: int) -> int:
address = self.memory_used
self.memory[self.memory_used] = size
self.memory.append(Instruction(Opcode.LD, Arg(size, ArgType.DIRECT)))
self.memory.append(Instruction(Opcode.ST, Arg(self.memory_used, ArgType.ADDRESS)))
self.memory_used += 1
for _ in range(size):
self.memory[self.memory_used] = 0
self.memory_used += 1
return address
def get_var_sp_offset(self, name: str) -> int | None:
for i in range(len(self.current_stack) - 1, -1, -1):
if self.current_stack[i].name == name:
return len(self.current_stack) - i - 1
return None
def to_machine_code(self) -> str:
memory = []
for i in range(len(self.memory)):
if isinstance(self.memory[i], Instruction):
instruction = cast(Instruction, self.memory[i])
instruction_dict = {"opcode": instruction.opcode.value, "address": i}
if instruction.arg is not None:
instruction_dict["arg"] = {
"value": instruction.arg.value,
"type": instruction.arg.arg_type.value,
}
if instruction.comment is not None:
instruction_dict["comment"] = instruction.comment
memory.append(instruction_dict)
return json.dumps({"memory": memory}, indent=4)
BINOP_OPCODE: dict[str, Opcode] = {
"+": Opcode.ADD,
"-": Opcode.SUB,
"=": Opcode.EQ,
"%": Opcode.MOD,
"/": Opcode.DIV,
"<": Opcode.LT,
">": Opcode.GT,
"*": Opcode.MUL,
}
def exec_binop(op: str, program: Program) -> None:
program.memory.append(Instruction(BINOP_OPCODE[op], Arg(0, ArgType.STACK_OFFSET)))
def _is_expression_start(tokens: list[Token], idx: int) -> bool:
return tokens[idx].token_type in (
Token.Type.OPEN_BRACKET,
Token.Type.INT,
Token.Type.BINOP,
Token.Type.IF,
Token.Type.SETQ,
Token.Type.IDENTIFIER,
Token.Type.STRING,
)
def get_expr_end_idx(tokens: list[Token], idx: int, started_with_open_bracket: bool) -> int:
if tokens[idx].token_type == Token.Type.CLOSE_BRACKET and started_with_open_bracket:
return idx + 1
if not started_with_open_bracket:
return idx
raise InvalidSymbolsError(got=tokens[idx], expected="close bracket")
def seek_end_of_expression(tokens: list[Token], idx: int) -> int:
if idx >= len(tokens):
return idx
if tokens[idx].token_type == Token.Type.OPEN_BRACKET:
idx += 1
while tokens[idx].token_type != Token.Type.CLOSE_BRACKET:
idx = seek_end_of_expression(tokens, idx)
return idx + 1
return idx + 1
def get_args_of_func(tokens: list[Token], idx: int) -> tuple[list[str], int]:
if tokens[idx].token_type != Token.Type.OPEN_BRACKET:
raise InvalidSymbolsError(got=tokens[idx], expected="open bracket")
idx += 1
passed_args: list[str] = []
while tokens[idx].token_type != Token.Type.CLOSE_BRACKET:
if tokens[idx].token_type != Token.Type.IDENTIFIER:
raise RuntimeError(EXPECTED_IDENTIFIER)
passed_args.append(tokens[idx].value)
idx += 1
return passed_args, idx + 1
def pass_args_to_func(tokens: list[Token], idx: int, result: Program) -> tuple[int, int]:
args_n = 0
while tokens[idx].token_type != Token.Type.CLOSE_BRACKET:
translate_expression(tokens, idx, result)
result.memory.append(Instruction(Opcode.PUSH, None, "Push arg"))
idx += 1
args_n += 1
return idx, args_n
def handle_token_int(tokens: list[Token], idx: int, result: Program, started_with_open_bracket: bool) -> int:
result.load(int(tokens[idx].value))
return get_expr_end_idx(tokens, idx + 1, started_with_open_bracket)
def handle_token_binop(tokens: list[Token], idx: int, result: Program, started_with_open_bracket: bool) -> int:
first_expr_end_idx: int = seek_end_of_expression(tokens, idx + 1)
second_expr_end_idx: int = translate_expression(tokens, first_expr_end_idx, result)
result.push_var_to_stack("#binop result")
translate_expression(tokens, idx + 1, result)
exec_binop(tokens[idx].value, result)
result.pop_var_from_stack()
return get_expr_end_idx(tokens, second_expr_end_idx, started_with_open_bracket)
def handle_token_if(tokens: list[Token], idx: int, result: Program, started_with_open_bracket: bool) -> int:
condition_end_idx: int = translate_expression(tokens, idx + 1, result)
je_idx: int = len(result.memory)
result.memory.append(Instruction(Opcode.JZ, None))
true_branch_end_idx: int = translate_expression(tokens, condition_end_idx, result)
jmp_idx: int = len(result.memory)
result.memory.append(Instruction(Opcode.JMP, None))
false_branch_memory_idx: int = len(result.memory)
false_branch_end_idx: int = translate_expression(tokens, true_branch_end_idx, result)
cast(Instruction, result.memory[je_idx]).arg = Arg(false_branch_memory_idx, ArgType.ADDRESS)
cast(Instruction, result.memory[jmp_idx]).arg = Arg(len(result.memory), ArgType.ADDRESS)
return get_expr_end_idx(tokens, false_branch_end_idx, started_with_open_bracket)
def handle_token_setq(tokens: list[Token], idx: int, result: Program, started_with_open_bracket: bool) -> int:
if tokens[idx + 1].token_type != Token.Type.IDENTIFIER:
raise RuntimeError(EXPECTED_IDENTIFIER)
expr_end_idx: int = translate_expression(tokens, idx + 2, result)
varname: str = tokens[idx + 1].value
var_sp_offset: int | None = result.get_var_sp_offset(varname)
if var_sp_offset is None:
result.push_var_to_stack(varname)
var_sp_offset = result.get_var_sp_offset(varname)
result.current_block_setq_count += 1
result.memory.append(Instruction(Opcode.ST, Arg(cast(int, var_sp_offset), ArgType.STACK_OFFSET)))
return get_expr_end_idx(tokens, expr_end_idx, started_with_open_bracket)
def handle_token_identifier(tokens: list[Token], idx: int, result: Program, started_with_open_bracket: bool) -> int:
if tokens[idx].value in result.functions:
args_end_idx, args_n = pass_args_to_func(tokens, idx + 1, result)
result.memory.append(Instruction(Opcode.CALL, Arg(result.functions[tokens[idx].value], ArgType.ADDRESS)))
for arg in range(args_n):
result.memory.append(Instruction(Opcode.POP, None, f"Pop arg {arg}"))
return get_expr_end_idx(tokens, args_end_idx, started_with_open_bracket)
result.memory.append(
Instruction(Opcode.LD, Arg(cast(int, result.get_var_sp_offset(tokens[idx].value)), ArgType.STACK_OFFSET))
)
return get_expr_end_idx(tokens, idx + 1, started_with_open_bracket)
def handle_token_progn(tokens: list[Token], idx: int, result: Program, started_with_open_bracket: bool) -> int:
idx += 1
while tokens[idx].token_type == Token.Type.OPEN_BRACKET:
idx = translate_expression(tokens, idx, result)
return get_expr_end_idx(tokens, idx, started_with_open_bracket)
def handle_token_string(tokens: list[Token], idx: int, result: Program, started_with_open_bracket: bool) -> int:
string_addr = result.alloc_string(tokens[idx].value)
result.load(string_addr)
return get_expr_end_idx(tokens, idx + 1, started_with_open_bracket)
def handle_token_print_char(tokens: list[Token], idx: int, result: Program, started_with_open_bracket: bool) -> int:
idx = translate_expression(tokens, idx + 1, result)
result.memory.append(Instruction(Opcode.OUT, None))
return get_expr_end_idx(tokens, idx, started_with_open_bracket)
def handle_token_print_string(tokens: list[Token], idx: int, result: Program, started_with_open_bracket: bool) -> int:
idx = translate_expression(tokens, idx + 1, result)
str_pointer_varname = "#str_p"
result.push_var_to_stack(str_pointer_varname)
# save string size:
# load string size to ac
result.memory.append(Instruction(Opcode.ST, Arg(SERVICE_VAR_ADDR, ArgType.ADDRESS)))
result.memory.append(
Instruction(Opcode.LD, Arg(SERVICE_VAR_ADDR, ArgType.INDIRECT), "Load string size inside print_str")
)
# store string size
result.push_var_to_stack("#str_size")
# init index
result.memory.append(Instruction(Opcode.LD, Arg(0, ArgType.DIRECT)))
result.push_var_to_stack("#i")
loop_start_idx: int = len(result.memory)
# compare index with string size:
# load index
result.memory.append(Instruction(Opcode.LD, Arg(cast(int, result.get_var_sp_offset("#i")), ArgType.STACK_OFFSET)))
result.memory.append(
Instruction(Opcode.EQ, Arg(cast(int, result.get_var_sp_offset("#str_size")), ArgType.STACK_OFFSET))
)
jnz_idx: int = len(result.memory)
# jump if index == string size
result.memory.append(Instruction(Opcode.JNZ, None))
# load string pointer
result.memory.append(
Instruction(Opcode.LD, Arg(cast(int, result.get_var_sp_offset(str_pointer_varname)), ArgType.STACK_OFFSET))
)
result.memory.append(Instruction(Opcode.ADD, Arg(cast(int, result.get_var_sp_offset("#i")), ArgType.STACK_OFFSET)))
result.memory.append(Instruction(Opcode.ADD, Arg(1, ArgType.DIRECT)))
# load char
result.memory.append(Instruction(Opcode.ST, Arg(SERVICE_VAR_ADDR, ArgType.ADDRESS)))
result.memory.append(Instruction(Opcode.LD, Arg(SERVICE_VAR_ADDR, ArgType.INDIRECT), "Load char inside print_str"))
result.memory.append(Instruction(Opcode.OUT, None))
# increment index
increment_index(result)
# jump to compare index with string size
result.memory.append(Instruction(Opcode.JMP, Arg(loop_start_idx, ArgType.ADDRESS), "Jump to read str loop start"))
cast(Instruction, result.memory[jnz_idx]).arg = Arg(len(result.memory), ArgType.ADDRESS)
result.memory.append(
Instruction(Opcode.LD, Arg(cast(int, result.get_var_sp_offset(str_pointer_varname)), ArgType.STACK_OFFSET))
)
result.pop_var_from_stack(comment="Pop #i used to print string")
result.pop_var_from_stack(comment="Pop #str_size used to print string")
result.pop_var_from_stack(comment="Pop #str_p used to print string")
return get_expr_end_idx(tokens, idx, started_with_open_bracket)
def increment_index(result, index_name: str = "#i"):
result.memory.append(Instruction(Opcode.LD, Arg(result.get_var_sp_offset(index_name), ArgType.STACK_OFFSET)))
result.memory.append(Instruction(Opcode.ADD, Arg(1, ArgType.DIRECT)))
result.memory.append(Instruction(Opcode.ST, Arg(result.get_var_sp_offset(index_name), ArgType.STACK_OFFSET)))
def handle_token_read_string(tokens: list[Token], idx: int, result: Program, started_with_open_bracket: bool) -> int:
if tokens[idx + 1].token_type != Token.Type.IDENTIFIER:
raise RuntimeError(EXPECTED_IDENTIFIER)
varname = tokens[idx + 1].value
var_sp_offset = result.get_var_sp_offset(varname)
if var_sp_offset is None:
result.push_var_to_stack(varname)
# alloc string
string_addr = result.alloc_string_of_size(STRING_ALLOC_SIZE)
result.memory.append(Instruction(Opcode.LD, Arg(string_addr, ArgType.DIRECT)))
str_pointer_varname = "#str_p"
result.push_var_to_stack(str_pointer_varname)
# index
result.memory.append(Instruction(Opcode.LD, Arg(1, ArgType.DIRECT)))
result.push_var_to_stack("#i")
char_varname = "#char"
result.push_var_to_stack(char_varname)
# cycle start
cycle_start_idx = len(result.memory)
# read char
result.memory.append(Instruction(Opcode.IN, None))
result.memory.append(
Instruction(Opcode.ST, Arg(cast(int, result.get_var_sp_offset(char_varname)), ArgType.STACK_OFFSET))
)
# if char is 0, then break
result.memory.append(Instruction(Opcode.EQ, Arg(0, ArgType.DIRECT)))
jz_idx = len(result.memory)
result.memory.append(Instruction(Opcode.JNZ, None))
# save char by index
result.memory.append(
Instruction(Opcode.LD, Arg(cast(int, result.get_var_sp_offset(str_pointer_varname)), ArgType.STACK_OFFSET))
)
result.memory.append(Instruction(Opcode.ADD, Arg(cast(int, result.get_var_sp_offset("#i")), ArgType.STACK_OFFSET)))
result.memory.append(Instruction(Opcode.ST, Arg(SERVICE_VAR_ADDR, ArgType.ADDRESS)))
result.memory.append(
Instruction(Opcode.LD, Arg(cast(int, result.get_var_sp_offset(char_varname)), ArgType.STACK_OFFSET))
)
result.memory.append(Instruction(Opcode.ST, Arg(SERVICE_VAR_ADDR, ArgType.INDIRECT), "Save char by index"))
increment_index(result)
# jump to cycle start
result.memory.append(Instruction(Opcode.JMP, Arg(cycle_start_idx, ArgType.ADDRESS)))
cast(Instruction, result.memory[jz_idx]).arg = Arg(len(result.memory), ArgType.ADDRESS)
# save string size
result.memory.append(
Instruction(Opcode.LD, Arg(cast(int, result.get_var_sp_offset(str_pointer_varname)), ArgType.STACK_OFFSET))
)
result.memory.append(Instruction(Opcode.ST, Arg(SERVICE_VAR_ADDR, ArgType.ADDRESS)))
result.memory.append(Instruction(Opcode.LD, Arg(cast(int, result.get_var_sp_offset("#i")), ArgType.STACK_OFFSET)))
result.memory.append(Instruction(Opcode.SUB, Arg(1, ArgType.DIRECT)))
result.memory.append(Instruction(Opcode.ST, Arg(SERVICE_VAR_ADDR, ArgType.INDIRECT), "Save string size"))
# save string pointer to variable
result.memory.append(
Instruction(Opcode.LD, Arg(cast(int, result.get_var_sp_offset(str_pointer_varname)), ArgType.STACK_OFFSET))
)
result.memory.append(
Instruction(Opcode.ST, Arg(cast(int, result.get_var_sp_offset(varname)), ArgType.STACK_OFFSET))
)
result.pop_var_from_stack(comment="Pop #i used to read string")
result.pop_var_from_stack(comment="Pop #char used to read string")
result.pop_var_from_stack(comment="Pop #str_p used to read string")
result.memory.append(
Instruction(Opcode.LD, Arg(cast(int, result.get_var_sp_offset(varname)), ArgType.STACK_OFFSET))
)
return get_expr_end_idx(tokens, idx + 2, started_with_open_bracket)
def handle_token_while(tokens: list[Token], idx: int, result: Program, started_with_open_bracket: bool) -> int:
loop_start_idx = len(result.memory)
condition_end_idx = translate_expression(tokens, idx + 1, result)
jz_idx = len(result.memory)
result.memory.append(Instruction(Opcode.JZ, None))
body_end_idx = translate_expression(tokens, condition_end_idx, result)
result.memory.append(Instruction(Opcode.JMP, Arg(loop_start_idx, ArgType.ADDRESS)))
cast(Instruction, result.memory[jz_idx]).arg = Arg(len(result.memory), ArgType.ADDRESS)
return get_expr_end_idx(tokens, body_end_idx, started_with_open_bracket)
def handle_token_defun(tokens: list[Token], idx: int, result: Program, started_with_open_bracket: bool) -> int:
if tokens[idx + 1].token_type != Token.Type.IDENTIFIER:
raise RuntimeError(EXPECTED_IDENTIFIER)
jmp_idx = len(result.memory)
result.memory.append(Instruction(Opcode.JMP, None))
result.functions[tokens[idx + 1].value] = len(result.memory)
# add variables to stack
stack_variables, args_end_idx = get_args_of_func(tokens, idx + 2)
for var in stack_variables:
result.resolve_stack_var(var)
result.resolve_stack_var("#ret_addr")
outer_setq_count = result.current_block_setq_count
result.current_block_setq_count = 0
body_end_idx = translate_expression(tokens, args_end_idx, result)
for _ in range(result.current_block_setq_count):
result.memory.append(Instruction(Opcode.POP, None, f"Pop local var of function {tokens[idx + 1].value}"))
result.current_block_setq_count = outer_setq_count
result.memory.append(Instruction(Opcode.RET, None))
cast(Instruction, result.memory[jmp_idx]).arg = Arg(len(result.memory), ArgType.ADDRESS)
for var in stack_variables:
result.unresolve_stack_var(var)
result.memory.append(Instruction(Opcode.LD, Arg(0, ArgType.DIRECT), "Load 0 so that defun expression returns 0"))
return get_expr_end_idx(tokens, body_end_idx, started_with_open_bracket)
def handle_token_open_bracket(tokens: list[Token], idx: int, result: Program, started_with_open_bracket: bool) -> int:
inside_expr_end_idx = translate_expression(tokens, idx + 1, result)
if tokens[inside_expr_end_idx].token_type != Token.Type.CLOSE_BRACKET:
raise InvalidSymbolsError(got=tokens[inside_expr_end_idx], expected="close bracket")
return get_expr_end_idx(tokens, inside_expr_end_idx + 1, started_with_open_bracket)
def handle_token_read_char(tokens: list[Token], idx: int, result: Program, started_with_open_bracket: bool) -> int:
varname = tokens[idx + 1].value
var_sp_offset = result.get_var_sp_offset(varname)
if var_sp_offset is None:
result.push_var_to_stack(varname)
result.memory.append(Instruction(Opcode.IN, None))
result.memory.append(
Instruction(Opcode.ST, Arg(cast(int, result.get_var_sp_offset(varname)), ArgType.STACK_OFFSET))
)
return get_expr_end_idx(tokens, idx + 2, started_with_open_bracket)
TOKEN_HANDLERS: dict[Token.Type, Callable[[list[Token], int, Program, bool], int]] = {
Token.Type.INT: handle_token_int,
Token.Type.BINOP: handle_token_binop,
Token.Type.IF: handle_token_if,
Token.Type.SETQ: handle_token_setq,
Token.Type.IDENTIFIER: handle_token_identifier,
Token.Type.PROGN: handle_token_progn,
Token.Type.STRING: handle_token_string,
Token.Type.PRINT_CHAR: handle_token_print_char,
Token.Type.PRINT_STRING: handle_token_print_string,
Token.Type.READ_STRING: handle_token_read_string,
Token.Type.WHILE: handle_token_while,
Token.Type.DEFUN: handle_token_defun,
Token.Type.OPEN_BRACKET: handle_token_open_bracket,
Token.Type.READ_CHAR: handle_token_read_char,
}
def translate_expression(tokens: list[Token], idx: int, result: Program) -> int:
if idx >= len(tokens):
return idx
if not _is_expression_start(tokens, idx):
raise InvalidSymbolsError(got=tokens[idx], expected="expression start")
started_with_open_bracket: bool = False
if tokens[idx].token_type == Token.Type.OPEN_BRACKET:
idx += 1
started_with_open_bracket = True
return TOKEN_HANDLERS[tokens[idx].token_type](tokens, idx, result, started_with_open_bracket)
def translate_program(tokens: list[Token], result: Program) -> None:
result.memory[0] = Instruction(Opcode.JMP, Arg(STATIC_MEMORY_SIZE, ArgType.ADDRESS), "Skip static memory")
result.memory_used = 2 # for jmp and for service var
translate_expression(tokens, 0, result)
result.memory.append(Instruction(Opcode.HLT, None))