1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
|
"""A lightweight python templating engine. Templet version 2 beta.
Supports two templating idioms:
1. template functions using @stringfunction and @unicodefunction
2. template classes inheriting from StringTemplate and UnicodeTemplate
Each template function is marked with the attribute @stringfunction
or @unicodefunction. Template functions will be rewritten to expand
their document string as a template and return the string result.
For example:
@stringtemplate
def myTemplate(animal, thing):
"the $animal jumped over the $thing."
print myTemplate('cow', 'moon')
The template language understands the following forms:
$myvar - inserts the value of the variable 'myvar'
${...} - evaluates the expression and inserts the result
${{...}} - executes enclosed code; use 'out.append(text)' to insert text
$$ - an escape for a single $
$ (at the end of the line) - a line continuation
Template functions are compiled into code that accumulates a list of
strings in a local variable 'out', and then returns the concatenation
of them. If you want do do complicated computation, you can append
to 'out' directly inside a ${{...}} block.
Another alternative is to use template classes.
Each template class is a subclass of StringTemplate or UnicodeTemplate.
Template classes should define a class attribute 'template' that
contains the template code. Also, any class attribute ending with
'_template' will be compiled into a template method.
Use a template class by instantiating it with a dictionary or
keyword arguments. Get the expansion by converting the instance
to a string. For example:
class MyTemplate(templet.Template):
template = "the $animal jumped over the $thing."
print MyTemplate(animal='cow', thing='moon')
Within a template class, the template language is similar to a template
function, but 'self.write' should be used to build the string inside
${{..}} blocks. Also, there is a shorthand for calling template methods:
$<sub_template> - shorthand for '${{self.sub_template(vars())}}'
This idiom is helpful for decomposing a template and when subclassing.
A longer example:
import cgi
class RecipeTemplate(templet.Template):
template = r'''
<html><head><title>$dish</title></head>
<body>
$<header_template>
$<body_template>
</body></html>
'''
header_template = r'''
<h1>${cgi.escape(dish)}</h1>
'''
body_template = r'''
<ol>
${{
for item in ingredients:
self.write('<li>', item, '\n')
}}
</ol>
'''
This template can be expanded as follows:
print RecipeTemplate(dish='burger', ingredients=['bun', 'beef', 'lettuce'])
And it can be subclassed like this:
class RecipeWithPriceTemplate(RecipeTemplate):
header_template = "<h1>${cgi.escape(dish)} - $$$price</h1>\n"
Templet is by David Bau and was inspired by Tomer Filiba's Templite class.
For details, see http://davidbau.com/templet
Templet is posted by David Bau under BSD-license terms.
Copyright (c) 2007, David Bau
All rights reserved.
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are met:
1. Redistributions of source code must retain the above copyright notice,
this list of conditions and the following disclaimer.
2. Redistributions in binary form must reproduce the above copyright
notice, this list of conditions and the following disclaimer in the
documentation and/or other materials provided with the distribution.
3. Neither the name of Templet nor the names of its contributors may
be used to endorse or promote products derived from this software
without specific prior written permission.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
"""
import sys, re, inspect
class _TemplateBuilder(object):
__pattern = re.compile(r"""\$( # Directives begin with a $
\$ | # $$ is an escape for $
[^\S\n]*\n | # $\n is a line continuation
[_a-z][_a-z0-9]* | # $simple Python identifier
\{(?!\{)[^\}]*\} | # ${...} expression to eval
\{\{.*?\}\} | # ${{...}} multiline code to exec
<[_a-z][_a-z0-9]*> | # $<sub_template> method call
)(?:(?:(?<=\}\})|(?<=>))[^\S\n]*\n)? # eat some trailing newlines
""", re.IGNORECASE | re.VERBOSE | re.DOTALL)
def __init__(self, constpat, emitpat, callpat=None):
self.constpat, self.emitpat, self.callpat = constpat, emitpat, callpat
def __realign(self, str, spaces=''):
"""Removes any leading empty columns of spaces and an initial empty line"""
lines = str.splitlines();
if lines and not lines[0].strip(): del lines[0]
lspace = [len(l) - len(l.lstrip()) for l in lines if l.lstrip()]
margin = len(lspace) and min(lspace)
return '\n'.join((spaces + l[margin:]) for l in lines)
def build(self, template, filename, s=''):
code = []
for i, part in enumerate(self.__pattern.split(self.__realign(template))):
if i % 2 == 0:
if part: code.append(s + self.constpat % repr(part))
else:
if not part or (part.startswith('<') and self.callpat is None):
raise SyntaxError('Unescaped $ in ' + filename)
elif part.endswith('\n'): continue
elif part == '$': code.append(s + self.emitpat % '"$"')
elif part.startswith('{{'): code.append(self.__realign(part[2:-2], s))
elif part.startswith('{'): code.append(s + self.emitpat % part[1:-1])
elif part.startswith('<'): code.append(s + self.callpat % part[1:-1])
else: code.append(s + self.emitpat % part)
return '\n'.join(code)
class _TemplateMetaClass(type):
__builder = _TemplateBuilder(
'self.out.append(%s)', 'self.write(%s)', 'self.%s(vars())')
def __compile(cls, template, n):
globals = sys.modules[cls.__module__].__dict__
if '__file__' not in globals: filename = '<%s %s>' % (cls.__name__, n)
else: filename = '%s: <%s %s>' % (globals['__file__'], cls.__name__, n)
code = compile(cls.__builder.build(template, filename), filename, 'exec')
def expand(self, __dict = None, **kw):
if __dict: kw.update([i for i in __dict.iteritems() if i[0] not in kw])
kw['self'] = self
exec code in globals, kw
return expand
def __init__(cls, *args):
for attr, val in cls.__dict__.items():
if attr == 'template' or attr.endswith('_template'):
if isinstance(val, basestring):
setattr(cls, attr, cls.__compile(val, attr))
type.__init__(cls, *args)
class StringTemplate(object):
"""A base class for string template classes."""
__metaclass__ = _TemplateMetaClass
def __init__(self, *args, **kw):
self.out = []
self.template(*args, **kw)
def write(self, *args):
self.out.extend([str(a) for a in args])
def __str__(self):
return ''.join(self.out)
# The original version of templet called StringTemplate "Template"
Template = StringTemplate
class UnicodeTemplate(object):
"""A base class for unicode template classes."""
__metaclass__ = _TemplateMetaClass
def __init__(self, *args, **kw):
self.out = []
self.template(*args, **kw)
def write(self, *args):
self.out.extend([unicode(a) for a in args])
def __unicode__(self):
return u''.join(self.out)
def __str__(self):
return unicode(self).encode('utf-8')
def _templatefunction(func, listname, stringtype):
globals, locals = sys.modules[func.__module__].__dict__, {}
if '__file__' not in globals: filename = '<%s>' % func.__name__
else: filename = '%s: <%s>' % (globals['__file__'], func.__name__)
builder = _TemplateBuilder('%s.append(%%s)' % listname,
'%s.append(%s(%%s))' % (listname, stringtype))
args = inspect.getargspec(func)
code = [
'def %s%s:' % (func.__name__, inspect.formatargspec(*args)),
' %s = []' % listname,
builder.build(func.__doc__, filename, ' '),
' return "".join(%s)' % listname]
code = compile('\n'.join(code), filename, 'exec')
exec code in globals, locals
return locals[func.__name__]
def stringfunction(func):
"""Function attribute for string template functions"""
return _templatefunction(func, listname='out', stringtype='str')
def unicodefunction(func):
"""Function attribute for unicode template functions"""
return _templatefunction(func, listname='out', stringtype='unicode')
# When executed as a script, run some testing code.
if __name__ == '__main__':
ok = True
def expect(actual, expected):
global ok
if expected != actual:
print "error - got:\n%s" % repr(actual)
ok = False
class TestAll(Template):
"""A test of all the $ forms"""
template = r"""
Bought: $count ${name}s$
at $$$price.
${{
for i in xrange(count):
self.write(TestCalls(vars()), "\n") # inherit all the local $vars
}}
Total: $$${"%.2f" % (count * price)}
"""
class TestCalls(Template):
"""A recursive test"""
template = "$name$i ${*[TestCalls(name=name[0], i=n) for n in xrange(i)]}"
expect(
str(TestAll(count=5, name="template call", price=1.23)),
"Bought: 5 template calls at $1.23.\n"
"template call0 \n"
"template call1 t0 \n"
"template call2 t0 t1 t0 \n"
"template call3 t0 t1 t0 t2 t0 t1 t0 \n"
"template call4 t0 t1 t0 t2 t0 t1 t0 t3 t0 t1 t0 t2 t0 t1 t0 \n"
"Total: $6.15\n")
class TestBase(Template):
template = r"""
<head>$<head_template></head>
<body>$<body_template></body>
"""
class TestDerived(TestBase):
head_template = "<title>$name</title>"
body_template = "${TestAll(vars())}"
expect(
str(TestDerived(count=4, name="template call", price=2.88)),
"<head><title>template call</title></head>\n"
"<body>"
"Bought: 4 template calls at $2.88.\n"
"template call0 \n"
"template call1 t0 \n"
"template call2 t0 t1 t0 \n"
"template call3 t0 t1 t0 t2 t0 t1 t0 \n"
"Total: $11.52\n"
"</body>\n")
class TestUnicode(UnicodeTemplate):
template = u"""
\N{Greek Small Letter Pi} = $pi
"""
expect(
unicode(TestUnicode(pi = 3.14)),
u"\N{Greek Small Letter Pi} = 3.14\n")
goterror = False
try:
class TestError(Template):
template = 'Cost of an error: $0'
except SyntaxError:
goterror = True
if not goterror:
print 'TestError failed'
ok = False
@stringfunction
def testBasic(name):
"Hello $name."
expect(testBasic('Henry'), "Hello Henry.")
@stringfunction
def testReps(a, count=5): r"""
${{ if count == 0: return '' }}
$a${testReps(a, count - 1)}"""
expect(
testReps('foo'),
"foofoofoofoofoo")
@unicodefunction
def testUnicode(count=4): u"""
${{ if not count: return '' }}
\N{BLACK STAR}${testUnicode(count - 1)}"""
expect(
testUnicode(count=10),
u"\N{BLACK STAR}" * 10)
if ok: print "OK"
|
