l2/main.py

"""Bootstrap compiler for the L2 language.

This file now contains working scaffolding for:

* Parsing definitions, literals, and ordinary word references.
* Respecting immediate/macro words so syntax can be rewritten on the fly.
* Emitting NASM-compatible x86-64 assembly with explicit data and return stacks.
* Driving the toolchain via ``nasm`` + ``ld``.
"""

from __future__ import annotations

import argparse
import subprocess
import sys
import textwrap
from dataclasses import dataclass, field
from pathlib import Path
from typing import Any, Callable, Dict, Iterable, List, Optional, Sequence, Set, Union, Tuple


class ParseError(Exception):
	"""Raised when the source stream cannot be parsed."""


class CompileError(Exception):
	"""Raised when IR cannot be turned into assembly."""


# ---------------------------------------------------------------------------
# Tokenizer / Reader
# ---------------------------------------------------------------------------


@dataclass
class Token:
	lexeme: str
	line: int
	column: int
	start: int
	end: int

	def __repr__(self) -> str:  # pragma: no cover - debug helper
		return f"Token({self.lexeme!r}@{self.line}:{self.column})"


class Reader:
	"""Default reader; users can swap implementations at runtime."""

	def __init__(self) -> None:
		self.line = 1
		self.column = 0

	def tokenize(self, source: str) -> Iterable[Token]:
		self.line = 1
		self.column = 0
		index = 0
		lexeme: List[str] = []
		token_start = 0
		token_line = 1
		token_column = 0
		source_len = len(source)
		while index < source_len:
			char = source[index]
			if char == "#":
				while index < source_len and source[index] != "\n":
					index += 1
				continue
			if char.isspace():
				if lexeme:
					yield Token(
						"".join(lexeme),
						token_line,
						token_column,
						token_start,
						index,
					)
					lexeme.clear()
				if char == "\n":
					self.line += 1
					self.column = 0
				else:
					self.column += 1
				index += 1
				continue
			if not lexeme:
				token_start = index
				token_line = self.line
				token_column = self.column
			lexeme.append(char)
			self.column += 1
			index += 1
		if lexeme:
			yield Token("".join(lexeme), token_line, token_column, token_start, index)


# ---------------------------------------------------------------------------
# Dictionary / Words
# ---------------------------------------------------------------------------


class ASTNode:
	"""Base class for all AST nodes."""


@dataclass
class WordRef(ASTNode):
	name: str


@dataclass
class Literal(ASTNode):
	value: Any


@dataclass
class Definition(ASTNode):
	name: str
	body: List[ASTNode]
	immediate: bool = False
	compile_only: bool = False


@dataclass
class AsmDefinition(ASTNode):
	name: str
	body: str
	immediate: bool = False
	compile_only: bool = False


@dataclass
class Module(ASTNode):
	forms: List[ASTNode]


@dataclass
class MacroDefinition:
	name: str
	tokens: List[str]
	param_count: int = 0


@dataclass
class StructField:
	name: str
	offset: int
	size: int


@dataclass
class BranchZero(ASTNode):
	target: str


@dataclass
class Jump(ASTNode):
	target: str


@dataclass
class Label(ASTNode):
	name: str


@dataclass
class ForBegin(ASTNode):
	loop_label: str
	end_label: str


@dataclass
class ForNext(ASTNode):
	loop_label: str
	end_label: str


class MacroContext:
	"""Small facade exposed to Python-defined macros."""

	def __init__(self, parser: "Parser") -> None:
		self._parser = parser

	@property
	def parser(self) -> "Parser":
		return self._parser

	def next_token(self) -> Token:
		return self._parser.next_token()

	def peek_token(self) -> Optional[Token]:
		return self._parser.peek_token()

	def emit_literal(self, value: int) -> None:
		self._parser.emit_node(Literal(value=value))

	def emit_word(self, name: str) -> None:
		self._parser.emit_node(WordRef(name=name))

	def emit_node(self, node: ASTNode) -> None:
		self._parser.emit_node(node)

	def inject_tokens(self, tokens: Sequence[str], template: Optional[Token] = None) -> None:
		if template is None:
			template = Token(lexeme="", line=0, column=0, start=0, end=0)
		generated = [
			Token(
				lexeme=lex,
				line=template.line,
				column=template.column,
				start=template.start,
				end=template.end,
			)
			for lex in tokens
		]
		self.inject_token_objects(generated)

	def inject_token_objects(self, tokens: Sequence[Token]) -> None:
		self._parser.tokens[self._parser.pos:self._parser.pos] = list(tokens)

	def enable_call_syntax(self) -> None:
		self._parser.call_syntax_enabled = True

	def disable_call_syntax(self) -> None:
		self._parser.call_syntax_enabled = False

	def new_label(self, prefix: str) -> str:
		return self._parser._new_label(prefix)

	def most_recent_definition(self) -> Optional[Word]:
		return self._parser.most_recent_definition()


MacroHandler = Callable[[MacroContext], Optional[List[ASTNode]]]
IntrinsicEmitter = Callable[["FunctionEmitter"], None]


@dataclass
class Word:
	name: str
	immediate: bool = False
	stack_effect: str = "( -- )"
	definition: Optional[Union[Definition, AsmDefinition]] = None
	macro: Optional[MacroHandler] = None
	intrinsic: Optional[IntrinsicEmitter] = None
	macro_expansion: Optional[List[str]] = None
	macro_params: int = 0
	compile_time_intrinsic: Optional[Callable[["CompileTimeVM"], None]] = None
	compile_only: bool = False


@dataclass
class Dictionary:
	words: Dict[str, Word] = field(default_factory=dict)

	def register(self, word: Word) -> None:
		if word.name in self.words:
			sys.stderr.write(f"[warn] redefining word {word.name}\n")
		self.words[word.name] = word

	def lookup(self, name: str) -> Optional[Word]:
		return self.words.get(name)


# ---------------------------------------------------------------------------
# Parser
# ---------------------------------------------------------------------------


Context = Union[Module, Definition]


class Parser:
	def __init__(self, dictionary: Dictionary) -> None:
		self.dictionary = dictionary
		self.tokens: List[Token] = []
		self.pos = 0
		self.context_stack: List[Context] = []
		self.definition_stack: List[Word] = []
		self.last_defined: Optional[Word] = None
		self.source: str = ""
		self.macro_recording: Optional[MacroDefinition] = None
		self.control_stack: List[Dict[str, str]] = []
		self.label_counter = 0
		self.call_syntax_enabled = False
		self.compile_time_vm = CompileTimeVM(self)

	# Public helpers for macros ------------------------------------------------
	def next_token(self) -> Token:
		return self._consume()

	def peek_token(self) -> Optional[Token]:
		return None if self._eof() else self.tokens[self.pos]

	def emit_node(self, node: ASTNode) -> None:
		self._append_node(node)

	def most_recent_definition(self) -> Optional[Word]:
		return self.last_defined

	# Parsing ------------------------------------------------------------------
	def parse(self, tokens: Iterable[Token], source: str) -> Module:
		self.tokens = list(tokens)
		self.source = source
		self.pos = 0
		self.context_stack = [Module(forms=[])]
		self.definition_stack.clear()
		self.last_defined = None
		self.control_stack = []
		self.label_counter = 0
		self.call_syntax_enabled = False

		while not self._eof():
			token = self._consume()
			if self._handle_macro_recording(token):
				continue
			lexeme = token.lexeme
			if lexeme == ":":
				self._begin_definition(token)
				continue
			if lexeme == ";":
				self._end_definition(token)
				continue
			if lexeme == ":asm":
				self._parse_asm_definition(token)
				continue
			if lexeme == ":py":
				self._parse_py_definition(token)
				continue
			if lexeme == "if":
				self._handle_if_control()
				continue
			if lexeme == "else":
				self._handle_else_control()
				continue
			if lexeme == "then":
				self._handle_then_control()
				continue
			if lexeme == "for":
				self._handle_for_control()
				continue
			if lexeme == "next":
				self._handle_next_control()
				continue
			if self._maybe_expand_macro(token):
				continue
			self._handle_token(token)

		if len(self.context_stack) != 1:
			raise ParseError("unclosed definition at EOF")
		if self.control_stack:
			raise ParseError("unclosed control structure at EOF")

		module = self.context_stack.pop()
		if not isinstance(module, Module):  # pragma: no cover - defensive
			raise ParseError("internal parser state corrupt")
		return module

	# Internal helpers ---------------------------------------------------------
	def _handle_token(self, token: Token) -> None:
		if self.call_syntax_enabled:
			call_target = self._maybe_call_form(token.lexeme)
			if call_target is not None:
				self._append_node(WordRef(name=call_target))
				return
		if self._try_literal(token):
			return

		word = self.dictionary.lookup(token.lexeme)
		if word and word.immediate:
			if word.macro:
				produced = word.macro(MacroContext(self))
				if produced:
					for node in produced:
						self._append_node(node)
			else:
				self._execute_immediate_word(word)
			return

		self._append_node(WordRef(name=token.lexeme))

	def _execute_immediate_word(self, word: Word) -> None:
		try:
			self.compile_time_vm.invoke(word)
		except ParseError:
			raise
		except Exception as exc:  # pragma: no cover - defensive
			raise ParseError(f"compile-time word '{word.name}' failed: {exc}") from exc

	def _handle_macro_recording(self, token: Token) -> bool:
		if self.macro_recording is None:
			return False
		if token.lexeme == ";macro":
			self._finish_macro_recording(token)
		else:
			self.macro_recording.tokens.append(token.lexeme)
		return True

	def _maybe_expand_macro(self, token: Token) -> bool:
		word = self.dictionary.lookup(token.lexeme)
		if word and word.macro_expansion is not None:
			args = self._collect_macro_args(word.macro_params)
			self._inject_macro_tokens(word, token, args)
			return True
		return False

	def _inject_macro_tokens(self, word: Word, token: Token, args: List[str]) -> None:
		replaced: List[str] = []
		for lex in word.macro_expansion or []:
			if lex.startswith("$"):
				idx = int(lex[1:]) - 1
				if idx < 0 or idx >= len(args):
					raise ParseError(f"macro {word.name} missing argument for {lex}")
				replaced.append(args[idx])
			else:
				replaced.append(lex)
		insertion = [
			Token(lexeme=lex, line=token.line, column=token.column, start=token.start, end=token.end)
			for lex in replaced
		]
		self.tokens[self.pos:self.pos] = insertion

	def _collect_macro_args(self, count: int) -> List[str]:
		args: List[str] = []
		for _ in range(count):
			if self._eof():
				raise ParseError("macro invocation missing arguments")
			args.append(self._consume().lexeme)
		return args

	def _start_macro_recording(self, name: str, param_count: int) -> None:
		if self.macro_recording is not None:
			raise ParseError("nested macro definitions are not supported")
		self.macro_recording = MacroDefinition(name=name, tokens=[], param_count=param_count)

	def _finish_macro_recording(self, token: Token) -> None:
		if self.macro_recording is None:
			raise ParseError(f"unexpected ';macro' at {token.line}:{token.column}")
		macro_def = self.macro_recording
		self.macro_recording = None
		word = Word(name=macro_def.name)
		word.macro_expansion = list(macro_def.tokens)
		word.macro_params = macro_def.param_count
		self.dictionary.register(word)

	def _push_control(self, entry: Dict[str, str]) -> None:
		self.control_stack.append(entry)

	def _pop_control(self, expected: Tuple[str, ...]) -> Dict[str, str]:
		if not self.control_stack:
			raise ParseError("control stack underflow")
		entry = self.control_stack.pop()
		if entry.get("type") not in expected:
			raise ParseError(f"mismatched control word '{entry.get('type')}'")
		return entry

	def _new_label(self, prefix: str) -> str:
		label = f"L_{prefix}_{self.label_counter}"
		self.label_counter += 1
		return label

	def _maybe_call_form(self, lexeme: str) -> Optional[str]:
		if len(lexeme) <= 2 or not lexeme.endswith("()"):
			return None
		name = lexeme[:-2]
		if not name or not _is_identifier(name):
			return None
		return name

	def _handle_if_control(self) -> None:
		false_label = self._new_label("if_false")
		self._append_node(BranchZero(target=false_label))
		self._push_control({"type": "if", "false": false_label})

	def _handle_else_control(self) -> None:
		entry = self._pop_control(("if",))
		end_label = self._new_label("if_end")
		self._append_node(Jump(target=end_label))
		self._append_node(Label(name=entry["false"]))
		self._push_control({"type": "else", "end": end_label})

	def _handle_then_control(self) -> None:
		entry = self._pop_control(("if", "else"))
		if entry["type"] == "if":
			self._append_node(Label(name=entry["false"]))
		else:
			self._append_node(Label(name=entry["end"]))

	def _handle_for_control(self) -> None:
		loop_label = self._new_label("for_loop")
		end_label = self._new_label("for_end")
		self._append_node(ForBegin(loop_label=loop_label, end_label=end_label))
		self._push_control({"type": "for", "loop": loop_label, "end": end_label})

	def _handle_next_control(self) -> None:
		entry = self._pop_control(("for",))
		self._append_node(ForNext(loop_label=entry["loop"], end_label=entry["end"]))

	def _begin_definition(self, token: Token) -> None:
		if self._eof():
			raise ParseError(f"definition name missing after ':' at {token.line}:{token.column}")
		name_token = self._consume()
		definition = Definition(name=name_token.lexeme, body=[])
		self.context_stack.append(definition)
		word = self.dictionary.lookup(definition.name)
		if word is None:
			word = Word(name=definition.name)
			self.dictionary.register(word)
		word.definition = definition
		self.definition_stack.append(word)

	def _end_definition(self, token: Token) -> None:
		if len(self.context_stack) <= 1:
			raise ParseError(f"unexpected ';' at {token.line}:{token.column}")
		ctx = self.context_stack.pop()
		if not isinstance(ctx, Definition):
			raise ParseError("';' can only close definitions")
		word = self.definition_stack.pop()
		ctx.immediate = word.immediate
		ctx.compile_only = word.compile_only
		module = self.context_stack[-1]
		if not isinstance(module, Module):
			raise ParseError("nested definitions are not supported yet")
		module.forms.append(ctx)
		self.last_defined = word

	def _parse_asm_definition(self, token: Token) -> None:
		if self._eof():
			raise ParseError(f"definition name missing after ':asm' at {token.line}:{token.column}")
		name_token = self._consume()
		brace_token = self._consume()
		if brace_token.lexeme != "{":
			raise ParseError(f"expected '{{' after asm name at {brace_token.line}:{brace_token.column}")
		block_start = brace_token.end
		block_end: Optional[int] = None
		while not self._eof():
			next_token = self._consume()
			if next_token.lexeme == "}":
				block_end = next_token.start
				break
		if block_end is None:
			raise ParseError("missing '}' to terminate asm body")
		asm_body = self.source[block_start:block_end]
		definition = AsmDefinition(name=name_token.lexeme, body=asm_body)
		word = self.dictionary.lookup(definition.name)
		if word is None:
			word = Word(name=definition.name)
			self.dictionary.register(word)
		word.definition = definition
		definition.immediate = word.immediate
		definition.compile_only = word.compile_only
		module = self.context_stack[-1]
		if not isinstance(module, Module):
			raise ParseError("asm definitions must be top-level forms")
		module.forms.append(definition)
		self.last_defined = word
		if self._eof():
			raise ParseError("asm definition missing terminator ';'")
		terminator = self._consume()
		if terminator.lexeme != ";":
			raise ParseError(f"expected ';' after asm definition at {terminator.line}:{terminator.column}")

	def _parse_py_definition(self, token: Token) -> None:
		if self._eof():
			raise ParseError(f"definition name missing after ':py' at {token.line}:{token.column}")
		name_token = self._consume()
		brace_token = self._consume()
		if brace_token.lexeme != "{":
			raise ParseError(f"expected '{{' after py name at {brace_token.line}:{brace_token.column}")
		block_start = brace_token.end
		block_end: Optional[int] = None
		while not self._eof():
			next_token = self._consume()
			if next_token.lexeme == "}":
				block_end = next_token.start
				break
		if block_end is None:
			raise ParseError("missing '}' to terminate py body")
		py_body = textwrap.dedent(self.source[block_start:block_end])
		word = self.dictionary.lookup(name_token.lexeme)
		if word is None:
			word = Word(name=name_token.lexeme)
		namespace = self._py_exec_namespace()
		try:
			exec(py_body, namespace)
		except Exception as exc:  # pragma: no cover - user code
			raise ParseError(f"python macro body for '{word.name}' raised: {exc}") from exc
		macro_fn = namespace.get("macro")
		intrinsic_fn = namespace.get("intrinsic")
		if macro_fn is None and intrinsic_fn is None:
			raise ParseError("python definition must define 'macro' or 'intrinsic'")
		if macro_fn is not None:
			word.macro = macro_fn
			word.immediate = True
		if intrinsic_fn is not None:
			word.intrinsic = intrinsic_fn
		self.dictionary.register(word)
		if self._eof():
			raise ParseError("py definition missing terminator ';'")
		terminator = self._consume()
		if terminator.lexeme != ";":
			raise ParseError(f"expected ';' after py definition at {terminator.line}:{terminator.column}")

	def _py_exec_namespace(self) -> Dict[str, Any]:
		return dict(PY_EXEC_GLOBALS)

	def _append_node(self, node: ASTNode) -> None:
		target = self.context_stack[-1]
		if isinstance(target, Module):
			target.forms.append(node)
		elif isinstance(target, Definition):
			target.body.append(node)
		else:  # pragma: no cover - defensive
			raise ParseError("unknown parse context")

	def _try_literal(self, token: Token) -> bool:
		try:
			value = int(token.lexeme, 0)
		except ValueError:
			string_value = _parse_string_literal(token)
			if string_value is None:
				return False
			self._append_node(Literal(value=string_value))
			return True
		self._append_node(Literal(value=value))
		return True

	def _consume(self) -> Token:
		if self._eof():
			raise ParseError("unexpected EOF")
		token = self.tokens[self.pos]
		self.pos += 1
		return token

	def _eof(self) -> bool:
		return self.pos >= len(self.tokens)


class CompileTimeVM:
	def __init__(self, parser: Parser) -> None:
		self.parser = parser
		self.dictionary = parser.dictionary
		self.stack: List[Any] = []
		self.return_stack: List[Any] = []

	def reset(self) -> None:
		self.stack.clear()
		self.return_stack.clear()

	def push(self, value: Any) -> None:
		self.stack.append(value)

	def pop(self) -> Any:
		if not self.stack:
			raise ParseError("compile-time stack underflow")
		return self.stack.pop()

	def peek(self) -> Any:
		if not self.stack:
			raise ParseError("compile-time stack underflow")
		return self.stack[-1]

	def pop_int(self) -> int:
		value = self.pop()
		if not isinstance(value, int):
			raise ParseError("expected integer on compile-time stack")
		return value

	def pop_str(self) -> str:
		value = self.pop()
		if not isinstance(value, str):
			raise ParseError("expected string on compile-time stack")
		return value

	def pop_list(self) -> List[Any]:
		value = self.pop()
		if not isinstance(value, list):
			raise ParseError("expected list on compile-time stack")
		return value

	def pop_token(self) -> Token:
		value = self.pop()
		if not isinstance(value, Token):
			raise ParseError("expected token on compile-time stack")
		return value

	def invoke(self, word: Word) -> None:
		self.reset()
		self._call_word(word)

	def _call_word(self, word: Word) -> None:
		if word.compile_time_intrinsic is not None:
			word.compile_time_intrinsic(self)
			return
		definition = word.definition
		if definition is None:
			raise ParseError(f"word '{word.name}' has no compile-time definition")
		if isinstance(definition, AsmDefinition):
			raise ParseError(f"word '{word.name}' cannot run at compile time")
		self._execute_nodes(definition.body)

	def _call_word_by_name(self, name: str) -> None:
		word = self.dictionary.lookup(name)
		if word is None:
			raise ParseError(f"unknown word '{name}' during compile-time execution")
		self._call_word(word)

	def _execute_nodes(self, nodes: Sequence[ASTNode]) -> None:
		label_positions = self._label_positions(nodes)
		loop_pairs = self._for_pairs(nodes)
		loop_stack: List[Dict[str, Any]] = []
		ip = 0
		while ip < len(nodes):
			node = nodes[ip]
			if isinstance(node, Literal):
				self.push(node.value)
				ip += 1
				continue
			if isinstance(node, WordRef):
				self._call_word_by_name(node.name)
				ip += 1
				continue
			if isinstance(node, BranchZero):
				condition = self.pop()
				flag: bool
				if isinstance(condition, bool):
					flag = condition
				elif isinstance(condition, int):
					flag = condition != 0
				else:
					raise ParseError("branch expects integer or boolean condition")
				if not flag:
					ip = self._jump_to_label(label_positions, node.target)
				else:
					ip += 1
				continue
			if isinstance(node, Jump):
				ip = self._jump_to_label(label_positions, node.target)
				continue
			if isinstance(node, Label):
				ip += 1
				continue
			if isinstance(node, ForBegin):
				count = self.pop_int()
				if count <= 0:
					match = loop_pairs.get(ip)
					if match is None:
						raise ParseError("internal loop bookkeeping error")
					ip = match + 1
					continue
				loop_stack.append({"remaining": count, "begin": ip})
				ip += 1
				continue
			if isinstance(node, ForNext):
				if not loop_stack:
					raise ParseError("'next' without matching 'for'")
				frame = loop_stack[-1]
				frame["remaining"] -= 1
				if frame["remaining"] > 0:
					ip = frame["begin"] + 1
					continue
				loop_stack.pop()
				ip += 1
				continue
			raise ParseError(f"unsupported compile-time AST node {node!r}")

	def _label_positions(self, nodes: Sequence[ASTNode]) -> Dict[str, int]:
		positions: Dict[str, int] = {}
		for idx, node in enumerate(nodes):
			if isinstance(node, Label):
				positions[node.name] = idx
		return positions

	def _for_pairs(self, nodes: Sequence[ASTNode]) -> Dict[int, int]:
		stack: List[int] = []
		pairs: Dict[int, int] = {}
		for idx, node in enumerate(nodes):
			if isinstance(node, ForBegin):
				stack.append(idx)
			elif isinstance(node, ForNext):
				if not stack:
					raise ParseError("'next' without matching 'for'")
				begin_idx = stack.pop()
				pairs[begin_idx] = idx
				pairs[idx] = begin_idx
		if stack:
			raise ParseError("'for' without matching 'next'")
		return pairs

	def _jump_to_label(self, labels: Dict[str, int], target: str) -> int:
		if target not in labels:
			raise ParseError(f"unknown label '{target}' during compile-time execution")
		return labels[target]


# ---------------------------------------------------------------------------
# NASM Emitter
# ---------------------------------------------------------------------------


@dataclass
class Emission:
	text: List[str] = field(default_factory=list)
	data: List[str] = field(default_factory=list)
	bss: List[str] = field(default_factory=list)

	def snapshot(self) -> str:
		parts: List[str] = []
		if self.text:
			parts.extend(["section .text", *self.text])
		if self.data:
			parts.extend(["section .data", *self.data])
		if self.bss:
			parts.extend(["section .bss", *self.bss])
		return "\n".join(parts)


class FunctionEmitter:
	"""Utility for emitting per-word assembly."""

	def __init__(self, text: List[str]) -> None:
		self.text = text

	def emit(self, line: str) -> None:
		self.text.append(line)

	def comment(self, message: str) -> None:
		self.text.append(f"    ; {message}")

	def push_literal(self, value: int) -> None:
		self.text.extend([
			f"    ; push {value}",
			"    sub r12, 8",
			f"    mov qword [r12], {value}",
		])

	def push_from(self, register: str) -> None:
		self.text.extend([
			"    sub r12, 8",
			f"    mov [r12], {register}",
		])

	def pop_to(self, register: str) -> None:
		self.text.extend([
			f"    mov {register}, [r12]",
			"    add r12, 8",
		])


def sanitize_label(name: str) -> str:
	parts: List[str] = []
	for ch in name:
		if ch.isalnum() or ch == "_":
			parts.append(ch)
		else:
			parts.append(f"_{ord(ch):02x}")
	safe = "".join(parts) or "anon"
	return f"word_{safe}"


def _is_identifier(text: str) -> bool:
	if not text:
		return False
	first = text[0]
	if not (first.isalpha() or first == "_"):
		return False
	return all(ch.isalnum() or ch == "_" for ch in text)


def _parse_string_literal(token: Token) -> Optional[str]:
	text = token.lexeme
	if len(text) < 2 or text[0] != '"' or text[-1] != '"':
		return None
	body = text[1:-1]
	result: List[str] = []
	idx = 0
	while idx < len(body):
		char = body[idx]
		if char != "\\":
			result.append(char)
			idx += 1
			continue
		idx += 1
		if idx >= len(body):
			raise ParseError(
				f"unterminated escape sequence in string literal at {token.line}:{token.column}"
			)
		escape = body[idx]
		idx += 1
		if escape == 'n':
			result.append("\n")
		elif escape == 't':
			result.append("\t")
		elif escape == 'r':
			result.append("\r")
		elif escape == '0':
			result.append("\0")
		elif escape == '"':
			result.append('"')
		elif escape == "\\":
			result.append("\\")
		else:
			raise ParseError(
				f"unsupported escape sequence '\\{escape}' in string literal at {token.line}:{token.column}"
			)
	return "".join(result)


class Assembler:
	def __init__(self, dictionary: Dictionary) -> None:
		self.dictionary = dictionary
		self.stack_bytes = 65536
		self.io_buffer_bytes = 128

	def emit(self, module: Module) -> Emission:
		emission = Emission()
		emission.text.extend(self._runtime_prelude())

		valid_defs = (Definition, AsmDefinition)
		definitions = [form for form in module.forms if isinstance(form, valid_defs)]
		stray_forms = [form for form in module.forms if not isinstance(form, valid_defs)]
		if stray_forms:
			raise CompileError("top-level literals or word references are not supported yet")

		runtime_defs = [
			defn for defn in definitions if not getattr(defn, "compile_only", False)
		]
		if not any(defn.name == "main" for defn in runtime_defs):
			raise CompileError("missing 'main' definition")

		for definition in runtime_defs:
			self._emit_definition(definition, emission.text)

		emission.bss.extend(self._bss_layout())
		return emission

	def _emit_definition(self, definition: Union[Definition, AsmDefinition], text: List[str]) -> None:
		label = sanitize_label(definition.name)
		text.append(f"{label}:")
		builder = FunctionEmitter(text)
		if isinstance(definition, Definition):
			for node in definition.body:
				self._emit_node(node, builder)
		elif isinstance(definition, AsmDefinition):
			self._emit_asm_body(definition, builder)
		else:  # pragma: no cover - defensive
			raise CompileError("unknown definition type")
		builder.emit("    ret")

	def _emit_asm_body(self, definition: AsmDefinition, builder: FunctionEmitter) -> None:
		body = definition.body.strip("\n")
		if not body:
			return
		for line in body.splitlines():
			if line.strip():
				builder.emit(line)
			else:
				builder.emit("")

	def _emit_node(self, node: ASTNode, builder: FunctionEmitter) -> None:
		if isinstance(node, Literal):
			if not isinstance(node.value, int):
				raise CompileError("string literals are compile-time only")
			builder.push_literal(node.value)
			return
		if isinstance(node, WordRef):
			self._emit_wordref(node, builder)
			return
		if isinstance(node, BranchZero):
			self._emit_branch_zero(node, builder)
			return
		if isinstance(node, Jump):
			builder.emit(f"    jmp {node.target}")
			return
		if isinstance(node, Label):
			builder.emit(f"{node.name}:")
			return
		if isinstance(node, ForBegin):
			self._emit_for_begin(node, builder)
			return
		if isinstance(node, ForNext):
			self._emit_for_next(node, builder)
			return
		raise CompileError(f"unsupported AST node {node!r}")

	def _emit_wordref(self, ref: WordRef, builder: FunctionEmitter) -> None:
		word = self.dictionary.lookup(ref.name)
		if word is None:
			raise CompileError(f"unknown word '{ref.name}'")
		if word.compile_only:
			raise CompileError(f"word '{ref.name}' is compile-time only")
		if word.intrinsic:
			word.intrinsic(builder)
			return
		builder.emit(f"    call {sanitize_label(ref.name)}")

	def _emit_branch_zero(self, node: BranchZero, builder: FunctionEmitter) -> None:
		builder.pop_to("rax")
		builder.emit("    test rax, rax")
		builder.emit(f"    jz {node.target}")

	def _emit_for_begin(self, node: ForBegin, builder: FunctionEmitter) -> None:
		builder.pop_to("rax")
		builder.emit("    cmp rax, 0")
		builder.emit(f"    jle {node.end_label}")
		builder.emit("    sub r13, 8")
		builder.emit("    mov [r13], rax")
		builder.emit(f"{node.loop_label}:")

	def _emit_for_next(self, node: ForNext, builder: FunctionEmitter) -> None:
		builder.emit("    mov rax, [r13]")
		builder.emit("    dec rax")
		builder.emit("    mov [r13], rax")
		builder.emit(f"    jg {node.loop_label}")
		builder.emit("    add r13, 8")
		builder.emit(f"{node.end_label}:")

	def _runtime_prelude(self) -> List[str]:
		return [
			"%define DSTK_BYTES 65536",
			"%define RSTK_BYTES 65536",
			"%define PRINT_BUF_BYTES 128",
			"global _start",
			"_start:",
			"    ; initialize data/return stack pointers",
			"    lea r12, [rel dstack_top]",
			"    mov r15, r12",
			"    lea r13, [rel rstack_top]",
			"    call word_main",
			"    mov rax, 0",
			"    cmp r12, r15",
			"    je .no_exit_value",
			"    mov rax, [r12]",
			"    add r12, 8",
			".no_exit_value:",
			"    mov rdi, rax",
			"    mov rax, 60",
			"    syscall",
		]

	def _bss_layout(self) -> List[str]:
		return [
			"align 16",
			"dstack: resb DSTK_BYTES",
			"dstack_top:",
			"align 16",
			"rstack: resb RSTK_BYTES",
			"rstack_top:",
			"align 16",
			"print_buf: resb PRINT_BUF_BYTES",
			"print_buf_end:",
		]

	def write_asm(self, emission: Emission, path: Path) -> None:
		path.write_text(emission.snapshot())


# ---------------------------------------------------------------------------
# Built-in macros and intrinsics
# ---------------------------------------------------------------------------


def macro_immediate(ctx: MacroContext) -> Optional[List[ASTNode]]:
	parser = ctx.parser
	word = parser.most_recent_definition()
	if word is None:
		raise ParseError("'immediate' must follow a definition")
	word.immediate = True
	if word.definition is not None:
		word.definition.immediate = True
	return None


def macro_compile_only(ctx: MacroContext) -> Optional[List[ASTNode]]:
	parser = ctx.parser
	word = parser.most_recent_definition()
	if word is None:
		raise ParseError("'compile-only' must follow a definition")
	word.compile_only = True
	if word.definition is not None:
		word.definition.compile_only = True
	return None


def macro_begin_text_macro(ctx: MacroContext) -> Optional[List[ASTNode]]:
	parser = ctx.parser
	if parser._eof():
		raise ParseError("macro name missing after 'macro:'")
	name_token = parser.next_token()
	param_count = 0
	peek = parser.peek_token()
	if peek is not None:
		try:
			param_count = int(peek.lexeme, 0)
			parser.next_token()
		except ValueError:
			param_count = 0
	parser._start_macro_recording(name_token.lexeme, param_count)
	return None


def macro_end_text_macro(ctx: MacroContext) -> Optional[List[ASTNode]]:
	parser = ctx.parser
	if parser.macro_recording is None:
		raise ParseError("';macro' without matching 'macro:'")
	# Actual closing handled in parser loop when ';macro' token is seen.
	return None


def _struct_emit_definition(tokens: List[Token], template: Token, name: str, body: Sequence[str]) -> None:
	def make_token(lexeme: str) -> Token:
		return Token(
			lexeme=lexeme,
			line=template.line,
			column=template.column,
			start=template.start,
			end=template.end,
		)

	tokens.append(make_token(":"))
	tokens.append(make_token(name))
	for lexeme in body:
		tokens.append(make_token(lexeme))
	tokens.append(make_token(";"))


class SplitLexer:
	def __init__(self, parser: Parser, separators: str) -> None:
		self.parser = parser
		self.separators = set(separators)
		self.buffer: List[Token] = []

	def _fill(self) -> None:
		while not self.buffer:
			if self.parser._eof():
				raise ParseError("unexpected EOF inside custom lexer")
			token = self.parser.next_token()
			parts = _split_token_by_chars(token, self.separators)
			if not parts:
				continue
			self.buffer.extend(parts)

	def peek(self) -> Token:
		self._fill()
		return self.buffer[0]

	def pop(self) -> Token:
		token = self.peek()
		self.buffer.pop(0)
		return token

	def expect(self, lexeme: str) -> Token:
		token = self.pop()
		if token.lexeme != lexeme:
			raise ParseError(f"expected '{lexeme}' but found '{token.lexeme}'")
		return token

	def collect_brace_block(self) -> List[Token]:
		depth = 1
		collected: List[Token] = []
		while depth > 0:
			token = self.pop()
			if token.lexeme == "{":
				depth += 1
				collected.append(token)
				continue
			if token.lexeme == "}":
				depth -= 1
				if depth == 0:
					break
				collected.append(token)
				continue
			collected.append(token)
		return collected

	def push_back(self) -> None:
		if not self.buffer:
			return
		self.parser.tokens[self.parser.pos:self.parser.pos] = self.buffer
		self.buffer = []


def _split_token_by_chars(token: Token, separators: Set[str]) -> List[Token]:
	lex = token.lexeme
	if not lex:
		return []
	parts: List[Token] = []
	idx = 0
	while idx < len(lex):
		char = lex[idx]
		if char in separators:
			parts.append(Token(
				lexeme=char,
				line=token.line,
				column=token.column + idx,
				start=token.start + idx,
				end=token.start + idx + 1,
			))
			idx += 1
			continue
		start_idx = idx
		while idx < len(lex) and lex[idx] not in separators:
			idx += 1
		segment = lex[start_idx:idx]
		if segment:
			parts.append(Token(
				lexeme=segment,
				line=token.line,
				column=token.column + start_idx,
				start=token.start + start_idx,
				end=token.start + idx,
			))
	return parts


def _ensure_list(value: Any) -> List[Any]:
	if not isinstance(value, list):
		raise ParseError("expected list value")
	return value


def _ensure_dict(value: Any) -> Dict[Any, Any]:
	if not isinstance(value, dict):
		raise ParseError("expected map value")
	return value


def _ensure_lexer(value: Any) -> SplitLexer:
	if not isinstance(value, SplitLexer):
		raise ParseError("expected lexer value")
	return value


def _truthy(value: Any) -> bool:
	if isinstance(value, bool):
		return value
	if isinstance(value, int):
		return value != 0
	return value is not None


def _coerce_str(value: Any) -> str:
	if isinstance(value, str):
		return value
	if isinstance(value, bool):
		return "1" if value else "0"
	if isinstance(value, int):
		return str(value)
	raise ParseError("expected string-compatible value")


def _default_template(template: Optional[Token]) -> Token:
	if template is None:
		return Token(lexeme="", line=0, column=0, start=0, end=0)
	if not isinstance(template, Token):
		raise ParseError("expected token for template")
	return template


def _trunc_divmod(a: int, b: int) -> Tuple[int, int]:
	if b == 0:
		raise ParseError("division by zero")
	quot = abs(a) // abs(b)
	if (a < 0) ^ (b < 0):
		quot = -quot
	rem = a - quot * b
	return quot, rem


def _ct_dup(vm: CompileTimeVM) -> None:
	vm.push(vm.peek())


def _ct_drop(vm: CompileTimeVM) -> None:
	vm.pop()


def _ct_swap(vm: CompileTimeVM) -> None:
	a = vm.pop()
	b = vm.pop()
	vm.push(a)
	vm.push(b)


def _ct_over(vm: CompileTimeVM) -> None:
	if len(vm.stack) < 2:
		raise ParseError("over requires two stack values")
	vm.push(vm.stack[-2])


def _ct_rot(vm: CompileTimeVM) -> None:
	if len(vm.stack) < 3:
		raise ParseError("rot requires three stack values")
	vm.stack[-3], vm.stack[-2], vm.stack[-1] = vm.stack[-2], vm.stack[-1], vm.stack[-3]


def _ct_nip(vm: CompileTimeVM) -> None:
	if len(vm.stack) < 2:
		raise ParseError("nip requires two stack values")
	top = vm.pop()
	vm.pop()
	vm.push(top)


def _ct_tuck(vm: CompileTimeVM) -> None:
	if len(vm.stack) < 2:
		raise ParseError("tuck requires two stack values")
	first = vm.pop()
	second = vm.pop()
	vm.push(first)
	vm.push(second)
	vm.push(first)


def _ct_2dup(vm: CompileTimeVM) -> None:
	if len(vm.stack) < 2:
		raise ParseError("2dup requires two stack values")
	second = vm.pop()
	first = vm.pop()
	vm.push(first)
	vm.push(second)
	vm.push(first)
	vm.push(second)


def _ct_2drop(vm: CompileTimeVM) -> None:
	if len(vm.stack) < 2:
		raise ParseError("2drop requires two stack values")
	vm.pop()
	vm.pop()


def _ct_2swap(vm: CompileTimeVM) -> None:
	if len(vm.stack) < 4:
		raise ParseError("2swap requires four stack values")
	a = vm.pop()
	b = vm.pop()
	c = vm.pop()
	d = vm.pop()
	vm.push(a)
	vm.push(b)
	vm.push(c)
	vm.push(d)


def _ct_2over(vm: CompileTimeVM) -> None:
	if len(vm.stack) < 4:
		raise ParseError("2over requires four stack values")
	vm.push(vm.stack[-4])
	vm.push(vm.stack[-3])


def _ct_minus_rot(vm: CompileTimeVM) -> None:
	if len(vm.stack) < 3:
		raise ParseError("-rot requires three stack values")
	vm.stack[-3], vm.stack[-2], vm.stack[-1] = vm.stack[-1], vm.stack[-3], vm.stack[-2]


def _ct_binary_int(vm: CompileTimeVM, func: Callable[[int, int], int]) -> None:
	b = vm.pop_int()
	a = vm.pop_int()
	vm.push(func(a, b))


def _ct_add(vm: CompileTimeVM) -> None:
	_ct_binary_int(vm, lambda a, b: a + b)


def _ct_sub(vm: CompileTimeVM) -> None:
	_ct_binary_int(vm, lambda a, b: a - b)


def _ct_mul(vm: CompileTimeVM) -> None:
	_ct_binary_int(vm, lambda a, b: a * b)


def _ct_div(vm: CompileTimeVM) -> None:
	divisor = vm.pop_int()
	dividend = vm.pop_int()
	quot, _ = _trunc_divmod(dividend, divisor)
	vm.push(quot)


def _ct_mod(vm: CompileTimeVM) -> None:
	divisor = vm.pop_int()
	dividend = vm.pop_int()
	_, rem = _trunc_divmod(dividend, divisor)
	vm.push(rem)


def _ct_compare(vm: CompileTimeVM, predicate: Callable[[Any, Any], bool]) -> None:
	b = vm.pop()
	a = vm.pop()
	vm.push(1 if predicate(a, b) else 0)


def _ct_eq(vm: CompileTimeVM) -> None:
	_ct_compare(vm, lambda a, b: a == b)


def _ct_ne(vm: CompileTimeVM) -> None:
	_ct_compare(vm, lambda a, b: a != b)


def _ct_lt(vm: CompileTimeVM) -> None:
	_ct_compare(vm, lambda a, b: a < b)


def _ct_le(vm: CompileTimeVM) -> None:
	_ct_compare(vm, lambda a, b: a <= b)


def _ct_gt(vm: CompileTimeVM) -> None:
	_ct_compare(vm, lambda a, b: a > b)


def _ct_ge(vm: CompileTimeVM) -> None:
	_ct_compare(vm, lambda a, b: a >= b)


def _ct_and(vm: CompileTimeVM) -> None:
	b = _truthy(vm.pop())
	a = _truthy(vm.pop())
	vm.push(1 if (a and b) else 0)


def _ct_or(vm: CompileTimeVM) -> None:
	b = _truthy(vm.pop())
	a = _truthy(vm.pop())
	vm.push(1 if (a or b) else 0)


def _ct_not(vm: CompileTimeVM) -> None:
	vm.push(1 if not _truthy(vm.pop()) else 0)


def _ct_to_r(vm: CompileTimeVM) -> None:
	vm.return_stack.append(vm.pop())


def _ct_r_from(vm: CompileTimeVM) -> None:
	if not vm.return_stack:
		raise ParseError("return stack underflow")
	vm.push(vm.return_stack.pop())


def _ct_rdrop(vm: CompileTimeVM) -> None:
	if not vm.return_stack:
		raise ParseError("return stack underflow")
	vm.return_stack.pop()


def _ct_rpick(vm: CompileTimeVM) -> None:
	index = vm.pop_int()
	if index < 0 or index >= len(vm.return_stack):
		raise ParseError("rpick index out of range")
	vm.push(vm.return_stack[-1 - index])


def _ct_nil(vm: CompileTimeVM) -> None:
	vm.push(None)


def _ct_nil_p(vm: CompileTimeVM) -> None:
	vm.push(1 if vm.pop() is None else 0)


def _ct_list_new(vm: CompileTimeVM) -> None:
	vm.push([])


def _ct_list_clone(vm: CompileTimeVM) -> None:
	lst = _ensure_list(vm.pop())
	vm.push(list(lst))


def _ct_list_append(vm: CompileTimeVM) -> None:
	value = vm.pop()
	lst = _ensure_list(vm.pop())
	lst.append(value)
	vm.push(lst)


def _ct_list_pop(vm: CompileTimeVM) -> None:
	lst = _ensure_list(vm.pop())
	if not lst:
		raise ParseError("cannot pop from empty list")
	value = lst.pop()
	vm.push(lst)
	vm.push(value)


def _ct_list_pop_front(vm: CompileTimeVM) -> None:
	lst = _ensure_list(vm.pop())
	if not lst:
		raise ParseError("cannot pop from empty list")
	value = lst.pop(0)
	vm.push(lst)
	vm.push(value)


def _ct_list_length(vm: CompileTimeVM) -> None:
	lst = _ensure_list(vm.pop())
	vm.push(len(lst))


def _ct_list_empty(vm: CompileTimeVM) -> None:
	lst = _ensure_list(vm.pop())
	vm.push(1 if not lst else 0)


def _ct_list_get(vm: CompileTimeVM) -> None:
	index = vm.pop_int()
	lst = _ensure_list(vm.pop())
	try:
		vm.push(lst[index])
	except IndexError as exc:
		raise ParseError("list index out of range") from exc


def _ct_list_set(vm: CompileTimeVM) -> None:
	value = vm.pop()
	index = vm.pop_int()
	lst = _ensure_list(vm.pop())
	try:
		lst[index] = value
	except IndexError as exc:
		raise ParseError("list index out of range") from exc
	vm.push(lst)


def _ct_list_clear(vm: CompileTimeVM) -> None:
	lst = _ensure_list(vm.pop())
	lst.clear()
	vm.push(lst)


def _ct_list_extend(vm: CompileTimeVM) -> None:
	source = _ensure_list(vm.pop())
	target = _ensure_list(vm.pop())
	target.extend(source)
	vm.push(target)


def _ct_list_last(vm: CompileTimeVM) -> None:
	lst = _ensure_list(vm.pop())
	if not lst:
		raise ParseError("list is empty")
	vm.push(lst[-1])


def _ct_map_new(vm: CompileTimeVM) -> None:
	vm.push({})


def _ct_map_set(vm: CompileTimeVM) -> None:
	value = vm.pop()
	key = vm.pop()
	map_obj = _ensure_dict(vm.pop())
	map_obj[key] = value
	vm.push(map_obj)


def _ct_map_get(vm: CompileTimeVM) -> None:
	key = vm.pop()
	map_obj = _ensure_dict(vm.pop())
	vm.push(map_obj)
	if key in map_obj:
		vm.push(map_obj[key])
		vm.push(1)
	else:
		vm.push(None)
		vm.push(0)


def _ct_map_has(vm: CompileTimeVM) -> None:
	key = vm.pop()
	map_obj = _ensure_dict(vm.pop())
	vm.push(map_obj)
	vm.push(1 if key in map_obj else 0)


def _ct_string_eq(vm: CompileTimeVM) -> None:
	right = vm.pop_str()
	left = vm.pop_str()
	vm.push(1 if left == right else 0)


def _ct_string_length(vm: CompileTimeVM) -> None:
	value = vm.pop_str()
	vm.push(len(value))


def _ct_string_append(vm: CompileTimeVM) -> None:
	right = vm.pop_str()
	left = vm.pop_str()
	vm.push(left + right)


def _ct_string_to_number(vm: CompileTimeVM) -> None:
	text = vm.pop_str()
	try:
		value = int(text, 0)
		vm.push(value)
		vm.push(1)
	except ValueError:
		vm.push(0)
		vm.push(0)


def _ct_int_to_string(vm: CompileTimeVM) -> None:
	value = vm.pop_int()
	vm.push(str(value))


def _ct_identifier_p(vm: CompileTimeVM) -> None:
	value = vm.pop_str()
	vm.push(1 if _is_identifier(value) else 0)


def _ct_token_lexeme(vm: CompileTimeVM) -> None:
	token = vm.pop_token()
	vm.push(token.lexeme)


def _ct_token_from_lexeme(vm: CompileTimeVM) -> None:
	template_value = vm.pop()
	lexeme = vm.pop_str()
	template = _default_template(template_value)
	vm.push(Token(
		lexeme=lexeme,
		line=template.line,
		column=template.column,
		start=template.start,
		end=template.end,
	))


def _ct_next_token(vm: CompileTimeVM) -> None:
	token = vm.parser.next_token()
	vm.push(token)


def _ct_peek_token(vm: CompileTimeVM) -> None:
	vm.push(vm.parser.peek_token())


def _ct_inject_tokens(vm: CompileTimeVM) -> None:
	tokens = _ensure_list(vm.pop())
	if not all(isinstance(item, Token) for item in tokens):
		raise ParseError("inject-tokens expects a list of tokens")
	vm.parser.inject_token_objects(tokens)


def _ct_emit_definition(vm: CompileTimeVM) -> None:
	body = _ensure_list(vm.pop())
	name_value = vm.pop()
	if isinstance(name_value, Token):
		template = name_value
		name = name_value.lexeme
	elif isinstance(name_value, str):
		template = _default_template(vm.pop())
		name = name_value
	else:
		raise ParseError("emit-definition expects token or string for name")
	lexemes = [
		item.lexeme if isinstance(item, Token) else _coerce_str(item)
		for item in body
	]
	generated: List[Token] = []
	_struct_emit_definition(generated, template, name, lexemes)
	vm.parser.inject_token_objects(generated)


def _ct_parse_error(vm: CompileTimeVM) -> None:
	message = vm.pop_str()
	raise ParseError(message)


def _ct_enable_call_syntax(vm: CompileTimeVM) -> None:
	vm.parser.call_syntax_enabled = True


def _ct_disable_call_syntax(vm: CompileTimeVM) -> None:
	vm.parser.call_syntax_enabled = False


def _ct_lexer_new(vm: CompileTimeVM) -> None:
	separators = vm.pop_str()
	vm.push(SplitLexer(vm.parser, separators))


def _ct_lexer_pop(vm: CompileTimeVM) -> None:
	lexer = _ensure_lexer(vm.pop())
	token = lexer.pop()
	vm.push(lexer)
	vm.push(token)


def _ct_lexer_peek(vm: CompileTimeVM) -> None:
	lexer = _ensure_lexer(vm.pop())
	vm.push(lexer)
	vm.push(lexer.peek())


def _ct_lexer_expect(vm: CompileTimeVM) -> None:
	lexeme = vm.pop_str()
	lexer = _ensure_lexer(vm.pop())
	token = lexer.expect(lexeme)
	vm.push(lexer)
	vm.push(token)


def _ct_lexer_collect_brace(vm: CompileTimeVM) -> None:
	lexer = _ensure_lexer(vm.pop())
	vm.push(lexer)
	vm.push(lexer.collect_brace_block())


def _ct_lexer_push_back(vm: CompileTimeVM) -> None:
	lexer = _ensure_lexer(vm.pop())
	lexer.push_back()
	vm.push(lexer)


def _register_compile_time_primitives(dictionary: Dictionary) -> None:
	def register(name: str, func: Callable[[CompileTimeVM], None], *, compile_only: bool = False) -> None:
		word = dictionary.lookup(name)
		if word is None:
			word = Word(name=name)
			dictionary.register(word)
		word.compile_time_intrinsic = func
		if compile_only:
			word.compile_only = True

	register("dup", _ct_dup)
	register("drop", _ct_drop)
	register("swap", _ct_swap)
	register("over", _ct_over)
	register("rot", _ct_rot)
	register("nip", _ct_nip)
	register("tuck", _ct_tuck)
	register("2dup", _ct_2dup)
	register("2drop", _ct_2drop)
	register("2swap", _ct_2swap)
	register("2over", _ct_2over)
	register("-rot", _ct_minus_rot)
	register("+", _ct_add)
	register("-", _ct_sub)
	register("*", _ct_mul)
	register("/", _ct_div)
	register("%", _ct_mod)
	register("==", _ct_eq)
	register("!=", _ct_ne)
	register("<", _ct_lt)
	register("<=", _ct_le)
	register(">", _ct_gt)
	register(">=", _ct_ge)
	register("and", _ct_and)
	register("or", _ct_or)
	register("not", _ct_not)
	register(">r", _ct_to_r)
	register("r>", _ct_r_from)
	register("rdrop", _ct_rdrop)
	register("rpick", _ct_rpick)

	register("nil", _ct_nil, compile_only=True)
	register("nil?", _ct_nil_p, compile_only=True)
	register("list-new", _ct_list_new, compile_only=True)
	register("list-clone", _ct_list_clone, compile_only=True)
	register("list-append", _ct_list_append, compile_only=True)
	register("list-pop", _ct_list_pop, compile_only=True)
	register("list-pop-front", _ct_list_pop_front, compile_only=True)
	register("list-length", _ct_list_length, compile_only=True)
	register("list-empty?", _ct_list_empty, compile_only=True)
	register("list-get", _ct_list_get, compile_only=True)
	register("list-set", _ct_list_set, compile_only=True)
	register("list-clear", _ct_list_clear, compile_only=True)
	register("list-extend", _ct_list_extend, compile_only=True)
	register("list-last", _ct_list_last, compile_only=True)

	register("map-new", _ct_map_new, compile_only=True)
	register("map-set", _ct_map_set, compile_only=True)
	register("map-get", _ct_map_get, compile_only=True)
	register("map-has?", _ct_map_has, compile_only=True)

	register("string=", _ct_string_eq, compile_only=True)
	register("string-length", _ct_string_length, compile_only=True)
	register("string-append", _ct_string_append, compile_only=True)
	register("string>number", _ct_string_to_number, compile_only=True)
	register("int>string", _ct_int_to_string, compile_only=True)
	register("identifier?", _ct_identifier_p, compile_only=True)

	register("token-lexeme", _ct_token_lexeme, compile_only=True)
	register("token-from-lexeme", _ct_token_from_lexeme, compile_only=True)
	register("next-token", _ct_next_token, compile_only=True)
	register("peek-token", _ct_peek_token, compile_only=True)
	register("inject-tokens", _ct_inject_tokens, compile_only=True)
	register("emit-definition", _ct_emit_definition, compile_only=True)
	register("parse-error", _ct_parse_error, compile_only=True)
	register("enable-call-syntax", _ct_enable_call_syntax, compile_only=True)
	register("disable-call-syntax", _ct_disable_call_syntax, compile_only=True)

	register("lexer-new", _ct_lexer_new, compile_only=True)
	register("lexer-pop", _ct_lexer_pop, compile_only=True)
	register("lexer-peek", _ct_lexer_peek, compile_only=True)
	register("lexer-expect", _ct_lexer_expect, compile_only=True)
	register("lexer-collect-brace", _ct_lexer_collect_brace, compile_only=True)
	register("lexer-push-back", _ct_lexer_push_back, compile_only=True)




PY_EXEC_GLOBALS: Dict[str, Any] = {
	"MacroContext": MacroContext,
	"Token": Token,
	"Literal": Literal,
	"WordRef": WordRef,
	"BranchZero": BranchZero,
	"Jump": Jump,
	"Label": Label,
	"ForBegin": ForBegin,
	"ForNext": ForNext,
	"StructField": StructField,
	"Definition": Definition,
	"Module": Module,
	"ParseError": ParseError,
	"emit_definition": _struct_emit_definition,
	"is_identifier": _is_identifier,
}


def macro_struct_begin(ctx: MacroContext) -> Optional[List[ASTNode]]:
	parser = ctx.parser
	if parser._eof():
		raise ParseError("struct name missing after 'struct:'")
	name_token = parser.next_token()
	struct_name = name_token.lexeme
	fields: List[StructField] = []
	current_offset = 0
	while True:
		if parser._eof():
			raise ParseError("unterminated struct definition (missing ';struct')")
		token = parser.next_token()
		if token.lexeme == ";struct":
			break
		if token.lexeme != "field":
			raise ParseError(f"expected 'field' or ';struct' in struct '{struct_name}' definition")
		if parser._eof():
			raise ParseError("field name missing in struct definition")
		field_name_token = parser.next_token()
		if parser._eof():
			raise ParseError(f"field size missing for '{field_name_token.lexeme}'")
		size_token = parser.next_token()
		try:
			field_size = int(size_token.lexeme, 0)
		except ValueError as exc:
			raise ParseError(
				f"invalid field size '{size_token.lexeme}' in struct '{struct_name}'"
			) from exc
		fields.append(StructField(field_name_token.lexeme, current_offset, field_size))
		current_offset += field_size

	generated: List[Token] = []
	_struct_emit_definition(generated, name_token, f"{struct_name}.size", [str(current_offset)])
	for field in fields:
		size_word = f"{struct_name}.{field.name}.size"
		offset_word = f"{struct_name}.{field.name}.offset"
		_struct_emit_definition(generated, name_token, size_word, [str(field.size)])
		_struct_emit_definition(generated, name_token, offset_word, [str(field.offset)])
		_struct_emit_definition(
			generated,
			name_token,
			f"{struct_name}.{field.name}@",
			[offset_word, "+", "@"],
		)
		_struct_emit_definition(
			generated,
			name_token,
			f"{struct_name}.{field.name}!",
			[offset_word, "+", "!"],
		)

	parser.tokens[parser.pos:parser.pos] = generated
	return None


def macro_struct_end(ctx: MacroContext) -> Optional[List[ASTNode]]:
	raise ParseError("';struct' must follow a 'struct:' block")


def bootstrap_dictionary() -> Dictionary:
	dictionary = Dictionary()
	dictionary.register(Word(name="immediate", immediate=True, macro=macro_immediate))
	dictionary.register(Word(name="compile-only", immediate=True, macro=macro_compile_only))
	dictionary.register(Word(name="macro:", immediate=True, macro=macro_begin_text_macro))
	dictionary.register(Word(name=";macro", immediate=True, macro=macro_end_text_macro))
	dictionary.register(Word(name="struct:", immediate=True, macro=macro_struct_begin))
	dictionary.register(Word(name=";struct", immediate=True, macro=macro_struct_end))
	_register_compile_time_primitives(dictionary)
	return dictionary


# ---------------------------------------------------------------------------
# Driver
# ---------------------------------------------------------------------------


class Compiler:
	def __init__(self) -> None:
		self.reader = Reader()
		self.dictionary = bootstrap_dictionary()
		self.parser = Parser(self.dictionary)
		self.assembler = Assembler(self.dictionary)

	def compile_source(self, source: str) -> Emission:
		tokens = list(self.reader.tokenize(source))
		module = self.parser.parse(tokens, source)
		return self.assembler.emit(module)

	def compile_file(self, path: Path) -> Emission:
		source = self._load_with_imports(path.resolve())
		return self.compile_source(source)

	def _load_with_imports(self, path: Path, seen: Optional[Set[Path]] = None) -> str:
		if seen is None:
			seen = set()
		path = path.resolve()
		if path in seen:
			return ""
		seen.add(path)
		try:
			contents = path.read_text()
		except FileNotFoundError as exc:
			raise ParseError(f"cannot import {path}: {exc}") from exc
		lines: List[str] = []
		for idx, line in enumerate(contents.splitlines()):
			stripped = line.strip()
			if stripped.startswith("import "):
				target = stripped.split(None, 1)[1].strip()
				if not target:
					raise ParseError(f"empty import target in {path}:{idx + 1}")
				target_path = (path.parent / target).resolve()
				lines.append(self._load_with_imports(target_path, seen))
				continue
			lines.append(line)
		return "\n".join(lines) + "\n"


def run_nasm(asm_path: Path, obj_path: Path) -> None:
	subprocess.run(["nasm", "-f", "elf64", "-o", str(obj_path), str(asm_path)], check=True)


def run_linker(obj_path: Path, exe_path: Path) -> None:
	subprocess.run(["ld", "-o", str(exe_path), str(obj_path)], check=True)


def cli(argv: Sequence[str]) -> int:
	parser = argparse.ArgumentParser(description="L2 compiler driver")
	parser.add_argument("source", type=Path, help="input .sl file")
	parser.add_argument("-o", dest="output", type=Path, default=Path("a.out"))
	parser.add_argument("--emit-asm", action="store_true", help="stop after generating asm")
	parser.add_argument("--temp-dir", type=Path, default=Path("build"))
	args = parser.parse_args(argv)

	compiler = Compiler()
	emission = compiler.compile_file(args.source)

	args.temp_dir.mkdir(parents=True, exist_ok=True)
	asm_path = args.temp_dir / (args.source.stem + ".asm")
	obj_path = args.temp_dir / (args.source.stem + ".o")
	compiler.assembler.write_asm(emission, asm_path)

	if args.emit_asm:
		print(f"[info] wrote {asm_path}")
		return 0

	run_nasm(asm_path, obj_path)
	run_linker(obj_path, args.output)
	print(f"[info] built {args.output}")
	return 0


def main() -> None:
	sys.exit(cli(sys.argv[1:]))


if __name__ == "__main__":
	main()