Engine for LaTeX songbooks http://www.patacrep.com
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#!/usr/bin/env python
# -*- coding: utf-8 -*-
import glob
import importlib
import jinja2
import logging
import os
from songbook_core.errors import SongbookError
LOGGER = logging.getLogger(__name__)
EOL = '\n'
class Content:
"""Content item of type 'example'."""
def render(self, context):
"""Render this content item.
Returns a string, to be placed verbatim in the generated .tex file.
"""
return ""
# Block management
def begin_new_block(self, previous, context):
"""Return a boolean stating if a new block is to be created.
# Arguments
- previous: the songbook.content.Content object of the previous item.
- context: TODO
# Return
True if the renderer has to close previous block, and begin a new one,
False otherwise.
"""
return True
def begin_block(self, context):
"""Return the string to begin a block."""
return ""
def end_block(self, context):
"""Return the string to end a block."""
return ""
class ContentError(SongbookError):
def __init__(self, keyword, message):
self.keyword = keyword
self.message = message
def __str__(self):
return "Content: {}: {}".format(self.keyword, self.message)
def load_plugins():
"""Load all content plugins, and return a dictionary of those plugins.
Return value: a dictionary where:
- keys are the keywords ;
- values are functions triggered when this keyword is met.
"""
plugins = {}
for name in glob.glob(os.path.join(os.path.dirname(__file__), "*.py")):
if name.endswith(".py") and os.path.basename(name) != "__init__.py":
plugin = importlib.import_module(
'songbook_core.content.{}'.format(os.path.basename(name[:-len('.py')]))
)
for (key, value) in plugin.CONTENT_PLUGINS.items():
if key in plugins:
LOGGER.warning("File %s: Keyword '%s' is already used. Ignored.", os.path.relpath(name), key)
continue
plugins[key] = value
return plugins
@jinja2.contextfunction
def render_content(context, content):
rendered = ""
previous = None
last = None
for elem in content:
if not isinstance(elem, Content):
LOGGER.error("Ignoring bad content item '{}'.".format(elem))
continue
last = elem
if elem.begin_new_block(previous, context):
if previous:
rendered += previous.end_block(context) + EOL
rendered += elem.begin_block(context) + EOL
rendered += elem.render(context) + EOL
previous = elem
if isinstance(last, Content):
rendered += last.end_block(context) + EOL
return rendered
def process_content(content, config = None):
contentlist = []
plugins = load_plugins()
for elem in content:
if isinstance(elem, basestring):
elem = ["song", elem]
if len(content) == 0:
content = ["song"]
if elem[0] not in plugins:
raise ContentError(elem[0], "Unknown content type.")
contentlist.extend(plugins[elem[0]](elem[0], config, *elem[1:]))
return contentlist