# templater.py - template expansion for output
#
# Copyright 2005, 2006 Matt Mackall <mpm@selenic.com>
#
# This software may be used and distributed according to the terms
# of the GNU General Public License, incorporated herein by reference.
from i18n import _
import re, sys, os
def parsestring(s, quoted=True):
'''parse a string using simple c-like syntax.
string must be in quotes if quoted is True.'''
if quoted:
if len(s) < 2 or s[0] != s[-1]:
raise SyntaxError(_('unmatched quotes'))
return s[1:-1].decode('string_escape')
return s.decode('string_escape')
class templater(object):
'''template expansion engine.
template expansion works like this. a map file contains key=value
pairs. if value is quoted, it is treated as string. otherwise, it
is treated as name of template file.
templater is asked to expand a key in map. it looks up key, and
looks for strings like this: {foo}. it expands {foo} by looking up
foo in map, and substituting it. expansion is recursive: it stops
when there is no more {foo} to replace.
expansion also allows formatting and filtering.
format uses key to expand each item in list. syntax is
{key%format}.
filter uses function to transform value. syntax is
{key|filter1|filter2|...}.'''
template_re = re.compile(r"(?:(?:#(?=[\w\|%]+#))|(?:{(?=[\w\|%]+})))"
r"(\w+)(?:(?:%(\w+))|((?:\|\w+)*))[#}]")
def __init__(self, mapfile, filters={}, defaults={}, cache={}):
'''set up template engine.
mapfile is name of file to read map definitions from.
filters is dict of functions. each transforms a value into another.
defaults is dict of default map definitions.'''
self.mapfile = mapfile or 'template'
self.cache = cache.copy()
self.map = {}
self.base = (mapfile and os.path.dirname(mapfile)) or ''
self.filters = filters
self.defaults = defaults
if not mapfile:
return
i = 0
for l in file(mapfile):
l = l.strip()
i += 1
if not l or l[0] in '#;': continue
m = re.match(r'([a-zA-Z_][a-zA-Z0-9_]*)\s*=\s*(.+)$', l)
if m:
key, val = m.groups()
if val[0] in "'\"":
try:
self.cache[key] = parsestring(val)
except SyntaxError, inst:
raise SyntaxError('%s:%s: %s' %
(mapfile, i, inst.args[0]))
else:
self.map[key] = os.path.join(self.base, val)
else:
raise SyntaxError(_("%s:%s: parse error") % (mapfile, i))
def __contains__(self, key):
return key in self.cache or key in self.map
def __call__(self, t, **map):
'''perform expansion.
t is name of map element to expand.
map is added elements to use during expansion.'''
if not t in self.cache:
try:
self.cache[t] = file(self.map[t]).read()
except IOError, inst:
raise IOError(inst.args[0], _('template file %s: %s') %
(self.map[t], inst.args[1]))
tmpl = self.cache[t]
while tmpl:
m = self.template_re.search(tmpl)
if not m:
yield tmpl
break
start, end = m.span(0)
key, format, fl = m.groups()
if start:
yield tmpl[:start]
tmpl = tmpl[end:]
if key in map:
v = map[key]
else:
v = self.defaults.get(key, "")
if callable(v):
v = v(**map)
if format:
if not hasattr(v, '__iter__'):
raise SyntaxError(_("Error expanding '%s%s'")
% (key, format))
lm = map.copy()
for i in v:
lm.update(i)
yield self(format, **lm)
else:
if fl:
for f in fl.split("|")[1:]:
v = self.filters[f](v)
yield v
def templatepath(name=None):
'''return location of template file or directory (if no name).
returns None if not found.'''
# executable version (py2exe) doesn't support __file__
if hasattr(sys, 'frozen'):
module = sys.executable
else:
module = __file__
for f in 'templates', '../templates':
fl = f.split('/')
if name: fl.append(name)
p = os.path.join(os.path.dirname(module), *fl)
if (name and os.path.exists(p)) or os.path.isdir(p):
return os.path.normpath(p)
def stringify(thing):
'''turn nested template iterator into string.'''
if hasattr(thing, '__iter__'):
return "".join([stringify(t) for t in thing if t is not None])
return str(thing)