"""Pygments lexers"""
from __future__ import annotations
import re
# this is not added as an entry point in ipython, so we add it in this package
from IPython.lib.lexers import IPythonTracebackLexer # noqa: F401
import pygments.lexer
import pygments.token
_ansi_code_to_color = {
0: "Black",
1: "Red",
2: "Green",
3: "Yellow",
4: "Blue",
5: "Magenta",
6: "Cyan",
7: "White",
}
def _token_from_lexer_state(
bold: bool, faint: bool, fg_color: str | None, bg_color: str | None
):
"""Construct a token given the current lexer state.
We can only emit one token even though we have a multiple-tuple state.
To do work around this, we construct tokens like "Bold.Red".
"""
components: tuple[str, ...] = ()
if bold:
components += ("Bold",)
if faint:
components += ("Faint",)
if fg_color:
components += (fg_color,)
if bg_color:
components += ("BG" + bg_color,)
if len(components) == 0:
return pygments.token.Text
else:
token = pygments.token.Token.Color
for component in components:
token = getattr(token, component)
return token
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class AnsiColorLexer(pygments.lexer.RegexLexer):
"""Pygments lexer for text containing ANSI color codes.
Adapted from https://github.com/chriskuehl/pygments-ansi-color
"""
name = "ANSI Color"
aliases = ("myst-ansi",)
flags = re.DOTALL | re.MULTILINE
def __init__(self, *args, **kwargs):
super().__init__(*args, **kwargs)
self.reset_state()
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def reset_state(self):
self.bold = False
self.faint = False
self.fg_color = None
self.bg_color = None
@property
def current_token(self):
return _token_from_lexer_state(
self.bold,
self.faint,
self.fg_color,
self.bg_color,
)
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def process(self, match):
"""Produce the next token and bit of text.
Interprets the ANSI code (which may be a color code or some other
code), changing the lexer state and producing a new token. If it's not
a color code, we just strip it out and move on.
Some useful reference for ANSI codes:
* http://ascii-table.com/ansi-escape-sequences.php
"""
# "after_escape" contains everything after the start of the escape
# sequence, up to the next escape sequence. We still need to separate
# the content from the end of the escape sequence.
after_escape = match.group(1)
# TODO: this doesn't handle the case where the values are non-numeric.
# This is rare but can happen for keyboard remapping, e.g.
# '\x1b[0;59;"A"p'
parsed = re.match(
r"([0-9;=]*?)?([a-zA-Z])(.*)$",
after_escape,
re.DOTALL | re.MULTILINE,
)
if parsed is None:
# This shouldn't ever happen if we're given valid text + ANSI, but
# people can provide us with utter junk, and we should tolerate it.
text = after_escape
else:
value, code, text = parsed.groups()
if code == "m": # "m" is "Set Graphics Mode"
# Special case \x1b[m is a reset code
if value == "":
self.reset_state()
else:
try:
values = [int(v) for v in value.split(";")]
except ValueError:
# Shouldn't ever happen, but could with invalid ANSI.
values = []
while len(values) > 0:
value = values.pop(0)
fg_color = _ansi_code_to_color.get(value - 30)
bg_color = _ansi_code_to_color.get(value - 40)
if fg_color:
self.fg_color = fg_color
elif bg_color:
self.bg_color = bg_color
elif value == 1:
self.bold = True
elif value == 2:
self.faint = True
elif value == 22:
self.bold = False
self.faint = False
elif value == 39:
self.fg_color = None
elif value == 49:
self.bg_color = None
elif value == 0:
self.reset_state()
elif value in (38, 48):
try:
five = values.pop(0)
color = values.pop(0)
except IndexError:
continue
else:
if five != 5:
continue
if not 0 <= color <= 255:
continue
if value == 38:
self.fg_color = f"C{color}"
else:
self.bg_color = f"C{color}"
yield match.start(), self.current_token, text
tokens = {
"root": [(r"\x1b\[([^\x1b]*)", process), (r"[^\x1b]+", pygments.token.Text)],
}
