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pystache_custom
Commit 01d5b389 by Chris Jerdonek
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Split off some of the Template class into a RenderEngine class (issue #58).

parent 984e5f5c
Showing with 266 additions and 216 deletions
pystache/renderengine.py 0 → 100644
# coding: utf-8
"""
Defines a class responsible for rendering logic.
"""
import re
try:
# The collections.Callable class is not available until Python 2.6.
import collections.Callable
def check_callable(it):
return isinstance(it, collections.Callable)
except ImportError:
def check_callable(it):
return hasattr(it, '__call__')
class Modifiers(dict):
"""Dictionary with a decorator for assigning functions to keys."""
def set(self, key):
"""
Return a decorator that assigns the given function to the given key.
>>> modifiers = {}
>>> @modifiers.set('P')
... def render_tongue(self, tag_name=None, context=None):
... return ":P %s" % tag_name
>>> modifiers
{'P': <function render_tongue at 0x...>}
"""
def decorate(func):
self[key] = func
return func
return decorate
class RenderEngine(object):
"""
Provides a render() method.
This class is meant only for internal use by the Template class.
"""
tag_re = None
otag = '{{'
ctag = '}}'
modifiers = Modifiers()
def __init__(self, load_template=None, literal=None, escape=None):
"""
Arguments:
escape: a function that takes a unicode or str string,
converts it to unicode, and escapes and returns it.
literal: a function that converts a unicode or str string
to unicode without escaping, and returns it.
"""
self.escape = escape
self.literal = literal
self.load_template = load_template
def render(self, template, context):
"""
Arguments:
template: a unicode template string.
context: a Context instance.
"""
self.context = context
self._compile_regexps()
return self._render(template)
def _compile_regexps(self):
"""
Compile and set the regular expression attributes.
This method uses the current values for the otag and ctag attributes.
"""
tags = {
'otag': re.escape(self.otag),
'ctag': re.escape(self.ctag)
}
# The section contents include white space to comply with the spec's
# requirement that sections not alter surrounding whitespace.
section = r"%(otag)s([#|^])([^\}]*)%(ctag)s(.+?)%(otag)s/\2%(ctag)s" % tags
self.section_re = re.compile(section, re.M|re.S)
tag = r"%(otag)s(#|=|&|!|>|\{)?(.+?)\1?%(ctag)s+" % tags
self.tag_re = re.compile(tag)
def _render_tags(self, template):
output = []
while True:
parts = self.tag_re.split(template, maxsplit=1)
output.append(parts[0])
if len(parts) < 2:
# Then there was no match.
break
start, tag_type, tag_name, template = parts
tag_name = tag_name.strip()
func = self.modifiers[tag_type]
tag_value = func(self, tag_name)
# Appending the tag value to the output prevents treating the
# value as a template string (bug: issue #44).
output.append(tag_value)
output = "".join(output)
return output
def _render_dictionary(self, template, context):
self.context.push(context)
out = self._render(template)
self.context.pop()
return out
def _render_list(self, template, listing):
insides = []
for item in listing:
insides.append(self._render_dictionary(template, item))
return ''.join(insides)
@modifiers.set(None)
def _render_tag(self, tag_name):
"""
Return the value of a variable as an escaped unicode string.
"""
raw = self.context.get(tag_name, '')
# For methods with no return value
#
# We use "==" rather than "is" to compare integers, as using "is" relies
# on an implementation detail of CPython. The test about rendering
# zeroes failed while using PyPy when using "is".
# See issue #34: https://github.com/defunkt/pystache/issues/34
if not raw and raw != 0:
if tag_name == '.':
raw = self.context.top()
else:
return ''
# If we don't first convert to a string type, the call to self._unicode_and_escape()
# will yield an error like the following:
#
# TypeError: coercing to Unicode: need string or buffer, ... found
#
if not isinstance(raw, basestring):
raw = str(raw)
return self.escape(raw)
@modifiers.set('!')
def _render_comment(self, tag_name):
return ''
@modifiers.set('>')
def _render_partial(self, template_name):
markup = self.load_template(template_name)
return self._render(markup)
@modifiers.set('=')
def _change_delimiter(self, tag_name):
"""
Change the current delimiter.
"""
self.otag, self.ctag = tag_name.split(' ')
self._compile_regexps()
return ''
@modifiers.set('{')
@modifiers.set('&')
def render_unescaped(self, tag_name):
"""
Render a tag without escaping it.
"""
return self.literal(self.context.get(tag_name, ''))
def _render(self, template):
"""
Arguments:
template: a unicode template string.
"""
output = []
while True:
parts = self.section_re.split(template, maxsplit=1)
start = self._render_tags(parts[0])
output.append(start)
if len(parts) < 2:
# Then there was no match.
break
section_type, section_key, section_contents, template = parts[1:]
section_key = section_key.strip()
section_value = self.context.get(section_key, None)
rendered = ''
# Callable
if section_value and check_callable(section_value):
rendered = section_value(section_contents)
# Dictionary
elif section_value and hasattr(section_value, 'keys') and hasattr(section_value, '__getitem__'):
if section_type != '^':
rendered = self._render_dictionary(section_contents, section_value)
# Lists
elif section_value and hasattr(section_value, '__iter__'):
if section_type != '^':
rendered = self._render_list(section_contents, section_value)
# Other objects
elif section_value and isinstance(section_value, object):
if section_type != '^':
rendered = self._render_dictionary(section_contents, section_value)
# Falsey and Negated or Truthy and Not Negated
elif (not section_value and section_type == '^') or (section_value and section_type != '^'):
rendered = self._render_dictionary(section_contents, section_value)
# Render template prior to section too
output.append(rendered)
output = "".join(output)
return output
pystache/template.py
......@@ -12,6 +12,7 @@ import sys
from .context import Context
from .loader import Loader
from .renderengine import RenderEngine
markupsafe = None
......@@ -21,46 +22,8 @@ except ImportError:
pass
try:
# The collections.Callable class is not available until Python 2.6.
import collections.Callable
def check_callable(it):
return isinstance(it, collections.Callable)
except ImportError:
def check_callable(it):
return hasattr(it, '__call__')
class Modifiers(dict):
"""Dictionary with a decorator for assigning functions to keys."""
def set(self, key):
"""
Return a decorator that assigns the given function to the given key.
>>> modifiers = {}
>>> @modifiers.set('P')
... def render_tongue(self, tag_name=None, context=None):
... return ":P %s" % tag_name
>>> modifiers
{'P': <function render_tongue at 0x...>}
"""
def decorate(func):
self[key] = func
return func
return decorate
class Template(object):
tag_re = None
otag = '{{'
ctag = '}}'
modifiers = Modifiers()
def __init__(self, template=None, load_template=None, output_encoding=None, escape=None,
default_encoding=None, decode_errors='strict'):
"""
......@@ -125,8 +88,6 @@ class Template(object):
self.output_encoding = output_encoding
self.template = template
self._compile_regexps()
def _unicode_and_escape(self, s):
if not isinstance(s, unicode):
s = self.unicode(s)
......@@ -159,7 +120,7 @@ class Template(object):
"""
return self._literal(self.unicode(s))
def _initialize_context(self, context, **kwargs):
def _make_context(self, context, **kwargs):
"""
Initialize the context attribute.
......@@ -175,179 +136,7 @@ class Template(object):
if kwargs:
context.push(kwargs)
self.context = context
def _compile_regexps(self):
"""
Compile and set the regular expression attributes.
This method uses the current values for the otag and ctag attributes.
"""
tags = {
'otag': re.escape(self.otag),
'ctag': re.escape(self.ctag)
}
# The section contents include white space to comply with the spec's
# requirement that sections not alter surrounding whitespace.
section = r"%(otag)s([#|^])([^\}]*)%(ctag)s(.+?)%(otag)s/\2%(ctag)s" % tags
self.section_re = re.compile(section, re.M|re.S)
tag = r"%(otag)s(#|=|&|!|>|\{)?(.+?)\1?%(ctag)s+" % tags
self.tag_re = re.compile(tag)
def _render(self, template):
"""
Arguments:
template: a unicode template string.
"""
output = []
while True:
parts = self.section_re.split(template, maxsplit=1)
start = self._render_tags(parts[0])
output.append(start)
if len(parts) < 2:
# Then there was no match.
break
section_type, section_key, section_contents, template = parts[1:]
section_key = section_key.strip()
section_value = self.context.get(section_key, None)
rendered = ''
# Callable
if section_value and check_callable(section_value):
rendered = section_value(section_contents)
# Dictionary
elif section_value and hasattr(section_value, 'keys') and hasattr(section_value, '__getitem__'):
if section_type != '^':
rendered = self._render_dictionary(section_contents, section_value)
# Lists
elif section_value and hasattr(section_value, '__iter__'):
if section_type != '^':
rendered = self._render_list(section_contents, section_value)
# Other objects
elif section_value and isinstance(section_value, object):
if section_type != '^':
rendered = self._render_dictionary(section_contents, section_value)
# Falsey and Negated or Truthy and Not Negated
elif (not section_value and section_type == '^') or (section_value and section_type != '^'):
rendered = self._render_dictionary(section_contents, section_value)
# Render template prior to section too
output.append(rendered)
output = "".join(output)
return output
def _render_tags(self, template):
output = []
while True:
parts = self.tag_re.split(template, maxsplit=1)
output.append(parts[0])
if len(parts) < 2:
# Then there was no match.
break
start, tag_type, tag_name, template = parts
tag_name = tag_name.strip()
func = self.modifiers[tag_type]
tag_value = func(self, tag_name)
# Appending the tag value to the output prevents treating the
# value as a template string (bug: issue #44).
output.append(tag_value)
output = "".join(output)
return output
def _render_dictionary(self, template, context):
self.context.push(context)
out = self._render(template)
self.context.pop()
return out
def _render_list(self, template, listing):
insides = []
for item in listing:
insides.append(self._render_dictionary(template, item))
return ''.join(insides)
@modifiers.set(None)
def _render_tag(self, tag_name):
"""
Return the value of a variable as an escaped unicode string.
"""
raw = self.context.get(tag_name, '')
# For methods with no return value
#
# We use "==" rather than "is" to compare integers, as using "is" relies
# on an implementation detail of CPython. The test about rendering
# zeroes failed while using PyPy when using "is".
# See issue #34: https://github.com/defunkt/pystache/issues/34
if not raw and raw != 0:
if tag_name == '.':
raw = self.context.top()
else:
return ''
# If we don't first convert to a string type, the call to self._unicode_and_escape()
# will yield an error like the following:
#
# TypeError: coercing to Unicode: need string or buffer, ... found
#
if not isinstance(raw, basestring):
raw = str(raw)
return self._unicode_and_escape(raw)
@modifiers.set('!')
def _render_comment(self, tag_name):
return ''
@modifiers.set('>')
def _render_partial(self, template_name):
markup = self.load_template(template_name)
return self._render(markup)
@modifiers.set('=')
def _change_delimiter(self, tag_name):
"""
Change the current delimiter.
"""
self.otag, self.ctag = tag_name.split(' ')
self._compile_regexps()
return ''
@modifiers.set('{')
@modifiers.set('&')
def render_unescaped(self, tag_name):
"""
Render a tag without escaping it.
"""
return self.literal(self.context.get(tag_name, ''))
return context
def render(self, context=None, **kwargs):
"""
......@@ -369,13 +158,17 @@ class Template(object):
These values take precedence over the context on any key conflicts.
"""
self._initialize_context(context, **kwargs)
context = self._make_context(context, **kwargs)
template = self.template
if not isinstance(template, unicode):
template = self.unicode(template)
result = self._render(template)
engine = RenderEngine(load_template=self.load_template,
literal=self.literal,
escape=self._unicode_and_escape)
result = engine.render(template, context)
if self.output_encoding is not None:
result = result.encode(self.output_encoding)
......
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