code_formatter.py revision 6651:9f6b8815d045 
1# Copyright (c) 2006-2009 Nathan Binkert <nate@binkert.org>
2# All rights reserved.
3#
4# Redistribution and use in source and binary forms, with or without
5# modification, are permitted provided that the following conditions are
6# met: redistributions of source code must retain the above copyright
7# notice, this list of conditions and the following disclaimer;
8# redistributions in binary form must reproduce the above copyright
9# notice, this list of conditions and the following disclaimer in the
10# documentation and/or other materials provided with the distribution;
11# neither the name of the copyright holders nor the names of its
12# contributors may be used to endorse or promote products derived from
13# this software without specific prior written permission.
14#
15# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
16# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
17# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
18# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
19# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
20# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
21# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
22# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
23# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
24# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
25# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
26
27import __builtin__
28import inspect
29import os
30import re
31import string
32
33class lookup(object):
34    def __init__(self, formatter, frame, *args, **kwargs):
35        self.frame = frame
36        self.formatter = formatter
37        self.dict = self.formatter._dict
38        self.args = args
39        self.kwargs = kwargs
40        self.locals = {}
41
42    def __setitem__(self, item, val):
43        self.locals[item] = val
44
45    def __getitem__(self, item):
46        if item in self.locals:
47            return self.locals[item]
48
49        if item in self.kwargs:
50            return self.kwargs[item]
51
52        if item == '__file__':
53            return self.frame.f_code.co_filename
54
55        if item == '__line__':
56            return self.frame.f_lineno
57
58        if item in self.dict:
59            return self.dict[item]
60
61        if self.formatter.locals or self.formatter.globals:
62            if self.formatter.locals and item in self.frame.f_locals:
63                return self.frame.f_locals[item]
64
65            if self.formatter.globals and item in self.frame.f_globals:
66                return self.frame.f_globals[item]
67
68        if item in __builtin__.__dict__:
69            return __builtin__.__dict__[item]
70
71        try:
72            item = int(item)
73            return self.args[item]
74        except ValueError:
75            pass
76        raise IndexError, "Could not find '%s'" % item
77
78class code_formatter_meta(type):
79    pattern = r"""
80    (?:
81      %(delim)s(?P<escaped>%(delim)s)              | # escaped delimiter
82      ^(?P<indent>[ ]*)%(delim)s(?P<lone>%(ident)s)$ | # lone identifier
83      %(delim)s(?P<ident>%(ident)s)                | # identifier
84      %(delim)s%(lb)s(?P<b_ident>%(ident)s)%(rb)s  | # braced identifier
85      %(delim)s(?P<pos>%(pos)s)                    | # positional parameter
86      %(delim)s%(lb)s(?P<b_pos>%(pos)s)%(rb)s      | # braced positional
87      %(delim)s%(ldb)s(?P<eval>.*?)%(rdb)s         | # double braced expression
88      %(delim)s(?P<invalid>)                       # ill-formed delimiter exprs
89    )
90    """
91    def __init__(cls, name, bases, dct):
92        super(code_formatter_meta, cls).__init__(name, bases, dct)
93        if 'pattern' in dct:
94            pat = cls.pattern
95        else:
96            # tuple expansion to ensure strings are proper length
97            lb,rb = cls.braced
98            lb1,lb2,rb2,rb1 = cls.double_braced
99            pat = code_formatter_meta.pattern % {
100                'delim' : re.escape(cls.delim),
101                'ident' : cls.ident,
102                'pos' : cls.pos,
103                'lb' : re.escape(lb),
104                'rb' : re.escape(rb),
105                'ldb' : re.escape(lb1+lb2),
106                'rdb' : re.escape(rb2+rb1),
107                }
108        cls.pattern = re.compile(pat, re.VERBOSE | re.DOTALL | re.MULTILINE)
109
110class code_formatter(object):
111    __metaclass__ = code_formatter_meta
112
113    delim = r'$'
114    ident = r'[_A-z]\w*'
115    pos = r'[0-9]+'
116    braced = r'{}'
117    double_braced = r'{{}}'
118
119    globals = True
120    locals = True
121    fix_newlines = True
122    def __init__(self, *args, **kwargs):
123        self._data = []
124        self._dict = {}
125        self._indent_level = 0
126        self._indent_spaces = 4
127        self.globals = kwargs.pop('globals',type(self).globals)
128        self.locals = kwargs.pop('locals', type(self).locals)
129        self._fix_newlines = \
130                kwargs.pop('fix_newlines', type(self).fix_newlines)
131
132        if args:
133            self.__call__(args)
134
135    def indent(self):
136        self._indent_level += self._indent_spaces
137
138    def dedent(self):
139        assert self._indent_level >= self._indent_spaces
140        self._indent_level -= self._indent_spaces
141
142    def fix(self, status):
143        previous = self._fix_newlines
144        self._fix_newlines = status
145        return previous
146
147    def nofix(self):
148        previous = self._fix_newlines
149        self._fix_newlines = False
150        return previous
151
152    def clear():
153        self._data = []
154
155    def write(self, *args):
156        f = file(os.path.join(*args), "w")
157        for data in self._data:
158            f.write(data)
159        f.close()
160
161    def __str__(self):
162        data = string.join(self._data, '')
163        self._data = [ data ]
164        return data
165
166    def __getitem__(self, item):
167        return self._dict[item]
168
169    def __setitem__(self, item, value):
170        self._dict[item] = value
171
172    def __delitem__(self, item):
173        del self._dict[item]
174
175    def __contains__(self, item):
176        return item in self._dict
177
178    def __iadd__(self, data):
179        self.append(data)
180
181    def append(self, data):
182        if isinstance(data, code_formatter):
183            self._data.extend(data._data)
184        else:
185            self._append(str(data))
186
187    def _append(self, data):
188        if not self._fix_newlines:
189            self._data.append(data)
190            return
191
192        initial_newline = not self._data or self._data[-1] == '\n'
193        for line in data.splitlines():
194            if line:
195                if self._indent_level:
196                    self._data.append(' ' * self._indent_level)
197                self._data.append(line)
198
199            if line or not initial_newline:
200                self._data.append('\n')
201
202            initial_newline = False
203
204    def insert_newline(self):
205        self._data.append('\n')
206
207    def __call__(self, format, *args, **kwargs):
208        frame = inspect.currentframe().f_back
209
210        l = lookup(self, frame, *args, **kwargs)
211        def convert(match):
212            ident = match.group('lone')
213            # check for a lone identifier
214            if ident:
215                indent = match.group('indent') # must be spaces
216                lone = '%s' % (l[ident], )
217
218                def indent_lines(gen):
219                    for line in gen:
220                        yield indent
221                        yield line
222                return ''.join(indent_lines(lone.splitlines(True)))
223
224            # check for an identifier, braced or not
225            ident = match.group('ident') or match.group('b_ident')
226            if ident is not None:
227                return '%s' % (l[ident], )
228
229            # check for a positional parameter, braced or not
230            pos = match.group('pos') or match.group('b_pos')
231            if pos is not None:
232                pos = int(pos)
233                if pos > len(args):
234                    raise ValueError \
235                        ('Positional parameter #%d not found in pattern' % pos,
236                         code_formatter.pattern)
237                return '%s' % (args[int(pos)], )
238
239            # check for a double braced expression
240            eval_expr = match.group('eval')
241            if eval_expr is not None:
242                result = eval(eval_expr, {}, l)
243                return '%s' % (result, )
244
245            # check for an escaped delimiter
246            if match.group('escaped') is not None:
247                return '$'
248
249            # At this point, we have to match invalid
250            if match.group('invalid') is None:
251                # didn't match invalid!
252                raise ValueError('Unrecognized named group in pattern',
253                                 code_formatter.pattern)
254
255            i = match.start('invalid')
256            if i == 0:
257                colno = 1
258                lineno = 1
259            else:
260                lines = format[:i].splitlines(True)
261                colno = i - reduce(lambda x,y: x+y, (len(z) for z in lines))
262                lineno = len(lines)
263
264                raise ValueError('Invalid format string: line %d, col %d' %
265                                 (lineno, colno))
266
267        d = code_formatter.pattern.sub(convert, format)
268        self._append(d)
269
270__all__ = [ "code_formatter" ]
271
272if __name__ == '__main__':
273    from code_formatter import code_formatter
274    f = code_formatter()
275
276    class Foo(dict):
277        def __init__(self, **kwargs):
278            self.update(kwargs)
279        def __getattr__(self, attr):
280            return self[attr]
281
282    x = "this is a test"
283    l = [ [Foo(x=[Foo(y=9)])] ]
284
285    y = code_formatter()
286    y('''
287{
288    this_is_a_test();
289}
290''')
291    f('    $y')
292    f('''$__file__:$__line__
293{''')
294    f("${{', '.join(str(x) for x in xrange(4))}}")
295    f('${x}')
296    f('$x')
297    f.indent()
298    for i in xrange(5):
299        f('$x')
300        f('$i')
301        f('$0', "zero")
302        f('$1 $0', "zero", "one")
303        f('${0}', "he went")
304        f('${0}asdf', "he went")
305    f.dedent()
306
307    f('''
308    ${{l[0][0]["x"][0].y}}
309}
310''', 1, 9)
311
312    print f,
313