IPython/utils/PyColorize.py

# -*- coding: utf-8 -*-
"""
Class and program to colorize python source code for ANSI terminals.

Based on an HTML code highlighter by Jurgen Hermann found at:
http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/52298

Modifications by Fernando Perez ([e-mail]).

Information on the original HTML highlighter follows:

MoinMoin - Python Source Parser

Title: Colorize Python source using the built-in tokenizer

Submitter: Jurgen Hermann
Last Updated:2001/04/06

Version no:1.2

Description:

This code is part of MoinMoin (http://moin.sourceforge.net/) and converts
Python source code to HTML markup, rendering comments, keywords,
operators, numeric and string literals in different colors.

It shows how to use the built-in keyword, token and tokenize modules to
scan Python source code and re-emit it with no changes to its original
formatting (which is the hard part).
"""

__all__ = ['ANSICodeColors','Parser']

_scheme_default = 'Linux'


# Imports
import keyword
import os
import sys
import token
import tokenize

generate_tokens = tokenize.generate_tokens

from IPython.utils.coloransi import TermColors, InputTermColors ,ColorScheme, ColorSchemeTable
from .colorable import Colorable
from io import StringIO

#############################################################################
### Python Source Parser (does Highlighting)
#############################################################################

_KEYWORD = token.NT_OFFSET + 1
_TEXT    = token.NT_OFFSET + 2

#****************************************************************************
# Builtin color schemes

Colors = TermColors  # just a shorthand

# Build a few color schemes
NoColor = ColorScheme(
    'NoColor',{
    'header'         : Colors.NoColor,
    token.NUMBER     : Colors.NoColor,
    token.OP         : Colors.NoColor,
    token.STRING     : Colors.NoColor,
    tokenize.COMMENT : Colors.NoColor,
    token.NAME       : Colors.NoColor,
    token.ERRORTOKEN : Colors.NoColor,

    _KEYWORD         : Colors.NoColor,
    _TEXT            : Colors.NoColor,

    'in_prompt'      : InputTermColors.NoColor,  # Input prompt
    'in_number'      : InputTermColors.NoColor,  # Input prompt number
    'in_prompt2'     : InputTermColors.NoColor, # Continuation prompt
    'in_normal'      : InputTermColors.NoColor,  # color off (usu. Colors.Normal)

    'out_prompt'     : Colors.NoColor, # Output prompt
    'out_number'     : Colors.NoColor, # Output prompt number

    'normal'         : Colors.NoColor  # color off (usu. Colors.Normal)
    }  )

LinuxColors = ColorScheme(
    'Linux',{
    'header'         : Colors.LightRed,
    token.NUMBER     : Colors.LightCyan,
    token.OP         : Colors.Yellow,
    token.STRING     : Colors.LightBlue,
    tokenize.COMMENT : Colors.LightRed,
    token.NAME       : Colors.Normal,
    token.ERRORTOKEN : Colors.Red,

    _KEYWORD         : Colors.LightGreen,
    _TEXT            : Colors.Yellow,

    'in_prompt'      : InputTermColors.Green,
    'in_number'      : InputTermColors.LightGreen,
    'in_prompt2'     : InputTermColors.Green,
    'in_normal'      : InputTermColors.Normal,  # color off (usu. Colors.Normal)

    'out_prompt'     : Colors.Red,
    'out_number'     : Colors.LightRed,

    'normal'         : Colors.Normal  # color off (usu. Colors.Normal)
    } )

NeutralColors = ColorScheme(
    'Neutral',{
    'header'         : Colors.Red,
    token.NUMBER     : Colors.Cyan,
    token.OP         : Colors.Blue,
    token.STRING     : Colors.Blue,
    tokenize.COMMENT : Colors.Red,
    token.NAME       : Colors.Normal,
    token.ERRORTOKEN : Colors.Red,

    _KEYWORD         : Colors.Green,
    _TEXT            : Colors.Blue,

    'in_prompt'      : InputTermColors.Blue,
    'in_number'      : InputTermColors.LightBlue,
    'in_prompt2'     : InputTermColors.Blue,
    'in_normal'      : InputTermColors.Normal,  # color off (usu. Colors.Normal)

    'out_prompt'     : Colors.Red,
    'out_number'     : Colors.LightRed,

    'normal'         : Colors.Normal  # color off (usu. Colors.Normal)
    }  )

# Hack: the 'neutral' colours are not very visible on a dark background on
# Windows. Since Windows command prompts have a dark background by default, and
# relatively few users are likely to alter that, we will use the 'Linux' colours,
# designed for a dark background, as the default on Windows. Changing it here
# avoids affecting the prompt colours rendered by prompt_toolkit, where the
# neutral defaults do work OK.

if os.name == 'nt':
    NeutralColors = LinuxColors.copy(name='Neutral')

LightBGColors = ColorScheme(
    'LightBG',{
    'header'         : Colors.Red,
    token.NUMBER     : Colors.Cyan,
    token.OP         : Colors.Blue,
    token.STRING     : Colors.Blue,
    tokenize.COMMENT : Colors.Red,
    token.NAME       : Colors.Normal,
    token.ERRORTOKEN : Colors.Red,


    _KEYWORD         : Colors.Green,
    _TEXT            : Colors.Blue,

    'in_prompt'      : InputTermColors.Blue,
    'in_number'      : InputTermColors.LightBlue,
    'in_prompt2'     : InputTermColors.Blue,
    'in_normal'      : InputTermColors.Normal,  # color off (usu. Colors.Normal)

    'out_prompt'     : Colors.Red,
    'out_number'     : Colors.LightRed,

    'normal'         : Colors.Normal  # color off (usu. Colors.Normal)
    }  )

# Build table of color schemes (needed by the parser)
ANSICodeColors = ColorSchemeTable([NoColor,LinuxColors,LightBGColors, NeutralColors],
                                  _scheme_default)

Undefined = object()

class Parser(Colorable):
    """ Format colored Python source.
    """

    def __init__(self, color_table=None, out = sys.stdout, parent=None, style=None):
        """ Create a parser with a specified color table and output channel.

        Call format() to process code.
        """

        super(Parser, self).__init__(parent=parent)

        self.color_table = color_table and color_table or ANSICodeColors
        self.out = out
        if not style:
            self.style = self.default_style
        else:
            self.style = style


    def format(self, raw, out=None, scheme=Undefined):
        import warnings
        if scheme is not Undefined:
            warnings.warn('The `scheme` argument of IPython.utils.PyColorize:Parser.format is deprecated since IPython 6.0.'
                          'It will have no effect. Set the parser `style` directly.',
                          stacklevel=2)
        return self.format2(raw, out)[0]

    def format2(self, raw, out = None):
        """ Parse and send the colored source.

        If out and scheme are not specified, the defaults (given to
        constructor) are used.

        out should be a file-type object. Optionally, out can be given as the
        string 'str' and the parser will automatically return the output in a
        string."""

        string_output = 0
        if out == 'str' or self.out == 'str' or \
           isinstance(self.out,StringIO):
            # XXX - I don't really like this state handling logic, but at this
            # point I don't want to make major changes, so adding the
            # isinstance() check is the simplest I can do to ensure correct
            # behavior.
            out_old = self.out
            self.out = StringIO()
            string_output = 1
        elif out is not None:
            self.out = out

        # Fast return of the unmodified input for NoColor scheme
        if self.style == 'NoColor':
            error = False
            self.out.write(raw)
            if string_output:
                return raw,error
            else:
                return None,error

        # local shorthands
        colors = self.color_table[self.style].colors
        self.colors = colors # put in object so __call__ sees it

        # Remove trailing whitespace and normalize tabs
        self.raw = raw.expandtabs().rstrip()

        # store line offsets in self.lines
        self.lines = [0, 0]
        pos = 0
        raw_find = self.raw.find
        lines_append = self.lines.append
        while 1:
            pos = raw_find('\n', pos) + 1
            if not pos: break
            lines_append(pos)
        lines_append(len(self.raw))

        # parse the source and write it
        self.pos = 0
        text = StringIO(self.raw)

        error = False
        try:
            for atoken in generate_tokens(text.readline):
                self(*atoken)
        except tokenize.TokenError as ex:
            msg = ex.args[0]
            line = ex.args[1][0]
            self.out.write("%s\n\n*** ERROR: %s%s%s\n" %
                           (colors[token.ERRORTOKEN],
                            msg, self.raw[self.lines[line]:],
                            colors.normal)
                           )
            error = True
        self.out.write(colors.normal+'\n')
        if string_output:
            output = self.out.getvalue()
            self.out = out_old
            return (output, error)
        return (None, error)

    def __call__(self, toktype, toktext, start_pos, end_pos, line):
        """ Token handler, with syntax highlighting."""
        (srow,scol) = start_pos
        (erow,ecol) = end_pos
        colors = self.colors
        owrite = self.out.write

        # line separator, so this works across platforms
        linesep = os.linesep

        # calculate new positions
        oldpos = self.pos
        newpos = self.lines[srow] + scol
        self.pos = newpos + len(toktext)

        # send the original whitespace, if needed
        if newpos > oldpos:
            owrite(self.raw[oldpos:newpos])

        # skip indenting tokens
        if toktype in [token.INDENT, token.DEDENT]:
            self.pos = newpos
            return

        # map token type to a color group
        if token.LPAR <= toktype <= token.OP:
            toktype = token.OP
        elif toktype == token.NAME and keyword.iskeyword(toktext):
            toktype = _KEYWORD
        color = colors.get(toktype, colors[_TEXT])

        #print '<%s>' % toktext,    # dbg

        # Triple quoted strings must be handled carefully so that backtracking
        # in pagers works correctly. We need color terminators on _each_ line.
        if linesep in toktext:
            toktext = toktext.replace(linesep, '%s%s%s' %
                                      (colors.normal,linesep,color))

        # send text
        owrite('%s%s%s' % (color,toktext,colors.normal))