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"""
mwrap_lexer.py — Line-oriented lexer for .mw files.
Copyright (c) 2007-2008 David Bindel
See the file COPYING for copying permissions
Converted to Python by Zydrunas Gimbutas (2026),
with assistance from Claude Code / Claude Opus 4.6 (Anthropic).
"""
import re
import sys
import os
from enum import Enum, auto
from dataclasses import dataclass
from typing import Optional, TextIO, List
class TokenType(Enum):
ID = auto()
NUMBER = auto()
STRING = auto()
NEW = auto()
FORTRAN = auto()
INPUT = auto()
OUTPUT = auto()
INOUT = auto()
CLASS = auto()
TYPEDEF = auto()
CPU = auto()
GPU = auto()
PUNCT = auto() # single characters: ( ) , ; * & [ ] . - > = :
NON_C_LINE = auto()
EOF = auto()
KEYWORDS = {
"new": TokenType.NEW,
"FORTRAN": TokenType.FORTRAN,
"input": TokenType.INPUT,
"output": TokenType.OUTPUT,
"inout": TokenType.INOUT,
"class": TokenType.CLASS,
"typedef": TokenType.TYPEDEF,
"cpu": TokenType.CPU,
"gpu": TokenType.GPU,
}
# Regex for tokenising a '#' line body
_TOKEN_RE = re.compile(
r"(//[^\n]*)" # comment (rest of line) — skip
r"|('[^'\n]*'?)" # string literal (single-quoted)
r"|((?:::)?[_a-zA-Z][_a-zA-Z0-9]*(?:::(?:[_a-zA-Z][_a-zA-Z0-9]*))*)" # ID (may have ::)
r"|([0-9]+)" # number
r"|([->()\[\],;*&=:.])" # punctuation
r"|[ \t\r]+" # whitespace — skip
)
@dataclass
class Token:
type: TokenType
value: str
line: int
def _is_name_char(c):
return c.isalnum() or c == '_'
def _fname_scan_line(text):
"""Extract function name from '@function ...' tail, return name.m."""
paren = text.find('(')
if paren < 0:
paren = len(text)
# Walk back from paren to find last alnum
end = paren
while end > 0 and not _is_name_char(text[end - 1]):
end -= 1
start = end
while start > 0 and _is_name_char(text[start - 1]):
start -= 1
name = text[start:end]
return name + ".m"
class Lexer:
"""Line-oriented lexer for .mw files.
Usage:
lex = Lexer(outfp, outcfp, mbatching_flag, listing_flag)
for tok in lex.lex_file(filename):
... # only tokens from '#' lines; NON_C_LINE for other lines
"""
def __init__(self, outfp=None, outcfp=None,
mbatching_flag=False, listing_flag=False):
self.outfp: Optional[TextIO] = outfp
self.outcfp: Optional[TextIO] = outcfp
self.mbatching_flag: bool = mbatching_flag
self.listing_flag: bool = listing_flag
self.linenum: int = 0
self.current_ifname: str = ""
# File include stack
self._file_stack: List = [] # [(fp, linenum, ifname), ...]
self._current_fp: Optional[TextIO] = None
# ------------------------------------------------------------------
# public interface
# ------------------------------------------------------------------
def lex_file(self, filename):
"""Yield Token objects from *filename*."""
fp = open(filename, "r")
self._current_fp = fp
self.current_ifname = filename
self.linenum = 1
yield from self._lex_stream()
# ------------------------------------------------------------------
# directive handlers
# ------------------------------------------------------------------
def _handle_block_c(self, line):
"""Process a line in block C mode. Returns False when block ends."""
stripped = line.rstrip('\r\n')
if re.match(r'^\$\][ \t\r]*$', stripped):
self.linenum += 1
return False
if self.outcfp:
self.outcfp.write(line)
self.linenum += 1
return True
def _handle_comment(self):
"""Handle // comment line."""
self.linenum += 1
yield Token(TokenType.NON_C_LINE, "", self.linenum - 1)
def _handle_function(self, stripped):
"""Handle @function directive."""
tail = stripped[len("@function"):]
tail = tail.rstrip('\r\n')
fname = _fname_scan_line(tail)
if self.mbatching_flag:
if self.outfp:
self.outfp.close()
try:
self.outfp = open(fname, "w")
except OSError:
print(f"Error: Could not write {fname}",
file=sys.stderr)
sys.exit(1)
if self.listing_flag:
print(fname)
if self.outfp:
self.outfp.write(f"function{tail}\n")
self.linenum += 1
yield Token(TokenType.NON_C_LINE, "", self.linenum - 1)
def _handle_include(self, stripped):
"""Handle @include directive. Pushes current file onto stack."""
rest = stripped[len("@include"):].strip().rstrip('\r\n')
if len(self._file_stack) >= 10:
print("Error: Includes nested too deeply",
file=sys.stderr)
sys.exit(1)
self._file_stack.append(
(self._current_fp, self.linenum, self.current_ifname))
try:
new_fp = open(rest, "r")
except OSError:
print(f"Error: Could not read '{rest}'",
file=sys.stderr)
sys.exit(1)
self.current_ifname = rest
self.linenum = 1
self._current_fp = new_fp
def _handle_redirect(self, stripped):
"""Handle @ redirect directive."""
rest = stripped[1:].strip().rstrip('\r\n')
if self.mbatching_flag:
if self.outfp:
self.outfp.close()
self.outfp = None
if rest:
try:
self.outfp = open(rest, "w")
except OSError:
print(f"Error: Could not write {rest}",
file=sys.stderr)
sys.exit(1)
if self.listing_flag and rest:
print(rest)
self.linenum += 1
yield Token(TokenType.NON_C_LINE, "", self.linenum - 1)
def _handle_dollar_line(self, stripped):
"""Handle $ single-line C pass-through."""
rest = stripped[1:]
if self.outcfp:
self.outcfp.write(rest)
self.linenum += 1
yield Token(TokenType.NON_C_LINE, "", self.linenum - 1)
def _handle_hash_line(self, stripped):
"""Handle # C declaration line — tokenise."""
body = stripped[1:].rstrip('\r\n')
yield from self._tokenize_c_line(body, self.linenum)
self.linenum += 1
# ------------------------------------------------------------------
# internal line-by-line driver
# ------------------------------------------------------------------
def _lex_stream(self):
"""Process all lines from self._current_fp, yielding tokens."""
in_block_c = False
while True:
raw_line = self._current_fp.readline()
if raw_line == "":
# End of current file
if self._file_stack:
self._current_fp.close()
self._current_fp, self.linenum, self.current_ifname = self._file_stack.pop()
continue
else:
return # real EOF
# Strip the trailing newline for processing but track it
line = raw_line
# --- block C mode ($[ ... $]) ---
if in_block_c:
in_block_c = self._handle_block_c(line)
continue
# Determine line prefix — compute leading whitespace
stripped = line.lstrip(' \t')
leading_ws = line[:len(line) - len(stripped)]
# In the original Flex lexer, leading [ \t] in INITIAL state is
# always written to outfp regardless of what prefix follows.
# We replicate this for all prefix types except pure text lines
# (which include their own leading whitespace in the full line).
if leading_ws and self.outfp and (
stripped.startswith("$") or
stripped.startswith("#") or
stripped.startswith("@") or
stripped.startswith("//")):
self.outfp.write(leading_ws)
# $[ block start
if re.match(r'^\$\[[ \t\r]*\n?$', stripped):
in_block_c = True
self.linenum += 1
continue
if stripped.startswith("//"):
yield from self._handle_comment()
continue
if stripped.startswith("@function"):
yield from self._handle_function(stripped)
continue
if stripped.startswith("@include"):
self._handle_include(stripped)
continue
if stripped.startswith("@"):
yield from self._handle_redirect(stripped)
continue
if stripped.startswith("$") and not stripped.startswith("$["):
yield from self._handle_dollar_line(stripped)
continue
if stripped.startswith("#"):
yield from self._handle_hash_line(stripped)
continue
# Text line — copy to MATLAB output
if self.outfp:
self.outfp.write(line)
self.linenum += 1
yield Token(TokenType.NON_C_LINE, "", self.linenum - 1)
# ------------------------------------------------------------------
# tokenise a single '#' line body
# ------------------------------------------------------------------
def _tokenize_c_line(self, body, line):
"""Yield tokens for the body of a '#' line."""
for m in _TOKEN_RE.finditer(body):
comment, string, ident, number, punct = m.groups()
if comment:
break # rest of line is a comment
if string:
yield Token(TokenType.STRING, string, line)
elif ident:
tt = KEYWORDS.get(ident, TokenType.ID)
yield Token(tt, ident, line)
elif number:
yield Token(TokenType.NUMBER, number, line)
elif punct:
yield Token(TokenType.PUNCT, punct, line)
|
