Engine for LaTeX songbooks http://www.patacrep.com
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# -*- coding: utf-8 -*-
r"""PlasTeX module to deal with chords commands of the songs LaTeX package
Chords are set using commands like \[C]. This package parses those commands.
"""
import logging
from plasTeX import Command, Environment, Macro
from plasTeX.Base.LaTeX.Math import BeginDisplayMath
LOGGER = logging.getLogger(__name__)
# Count the number of levels of 'verse' environment: IN_VERSE==1 means that we
# are in a 'verse' environment; IN_VERSE==2 means that we are in two included
# 'verse' environment, and so on.
IN_VERSE = 0
def wrap_displaymath(cls):
"""Decorator to store the depth of 'verse' environment
In the invoke() method classes, global variable IN_VERSE indicates the
number of 'verse' (or 'chorus' or 'verse*') environment we are in.
"""
# pylint: disable=no-init,too-few-public-methods
class DisplayMath(cls):
"""Wrapper to LaTeX environment updating IN_VERSE"""
blockType = True
# pylint: disable=super-on-old-class,global-statement,no-member
def invoke(self, tex):
"""Wrapper to invoke() to update global variable IN_VERSE."""
global IN_VERSE
if self.macroMode == Macro.MODE_BEGIN:
IN_VERSE += 1
else:
IN_VERSE -= 1
super(DisplayMath, self).invoke(tex)
return DisplayMath
# pylint: disable=too-many-public-methods
@wrap_displaymath
class Verse(Environment):
"""LaTeX 'verse' environment"""
macroName = 'verse'
# pylint: disable=too-many-public-methods
@wrap_displaymath
class VerseStar(Environment):
"""LaTeX 'verse*' environment"""
macroName = 'verse*'
# pylint: disable=too-many-public-methods
@wrap_displaymath
class Chorus(Environment):
"""LaTeX 'chorus' environment"""
macroName = 'chorus'
class Chord(Command):
"""Beginning of a chord notation"""
macroName = 'chord'
macroMode = Command.MODE_NONE
def __init__(self, *args, **kwargs):
super(Chord, self).__init__(*args, **kwargs)
self.chord = ""
@property
def source(self):
"""Return chord LaTeX code."""
return r'\[{}]'.format(self.chord)
class BeginChordOrDisplayMath(BeginDisplayMath):
r"""Wrapper to BeginDisplayMath
In a 'verse' (or 'verse*' or 'chorus') environment, the '\[' macro
displays a chord. Otherwise, it corresponds to the usual LaTeX math mode.
This class calls the right method, depending on the inclusion of this
macro in a verse environment.
"""
macroName = '['
def digest(self, tokens):
"""Consume the tokens corresponding to the arguments of this macro"""
if IN_VERSE:
for item in tokens:
if item.nodeType == item.TEXT_NODE and item.nodeValue == ']':
break
self.appendChild(item)
else:
return super(BeginChordOrDisplayMath, self).digest(tokens)
def invoke(self, tex):
"""Process this macro"""
if IN_VERSE:
chord = Chord()
for token in tex:
if token.nodeType == token.TEXT_NODE and token.nodeValue == ']':
break
else:
if token.nodeName == '#text':
chord.chord += str(token)
elif token.nodeName == "active::&":
chord.chord += '&'
else:
LOGGER.warning((
"{}: Unexpected character '{}' in chord "
"argument. Continuing anyway.").format(
tex.filename,
token.source,
))
break
return [chord]
else:
return super(BeginChordOrDisplayMath, self).invoke(tex)