1# coding=utf-8
2#
3# Copyright © 2011 Intel Corporation
4#
5# Permission is hereby granted, free of charge, to any person obtaining a
6# copy of this software and associated documentation files (the "Software"),
7# to deal in the Software without restriction, including without limitation
8# the rights to use, copy, modify, merge, publish, distribute, sublicense,
9# and/or sell copies of the Software, and to permit persons to whom the
10# Software is furnished to do so, subject to the following conditions:
11#
12# The above copyright notice and this permission notice (including the next
13# paragraph) shall be included in all copies or substantial portions of the
14# Software.
15#
16# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
17# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
18# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
19# THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
20# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
21# FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
22# DEALINGS IN THE SOFTWARE.
23
24# This file contains helper functions for manipulating sexps in Python.
25#
26# We represent a sexp in Python using nested lists containing strings.
27# So, for example, the sexp (constant float (1.000000)) is represented
28# as ['constant', 'float', ['1.000000']].
29
30import re
31
32def check_sexp(sexp):
33    """Verify that the argument is a proper sexp.
34
35    That is, raise an exception if the argument is not a string or a
36    list, or if it contains anything that is not a string or a list at
37    any nesting level.
38    """
39    if isinstance(sexp, list):
40        for s in sexp:
41            check_sexp(s)
42    elif not isinstance(sexp, basestring):
43        raise Exception('Not a sexp: {0!r}'.format(sexp))
44
45def parse_sexp(sexp):
46    """Convert a string, of the form that would be output by mesa,
47    into a sexp represented as nested lists containing strings.
48    """
49    sexp_token_regexp = re.compile(
50        '[a-zA-Z_]+(@[0-9]+)?|[0-9]+(\\.[0-9]+)?|[^ \n]')
51    stack = [[]]
52    for match in sexp_token_regexp.finditer(sexp):
53        token = match.group(0)
54        if token == '(':
55            stack.append([])
56        elif token == ')':
57            if len(stack) == 1:
58                raise Exception('Unmatched )')
59            sexp = stack.pop()
60            stack[-1].append(sexp)
61        else:
62            stack[-1].append(token)
63    if len(stack) != 1:
64        raise Exception('Unmatched (')
65    if len(stack[0]) != 1:
66        raise Exception('Multiple sexps')
67    return stack[0][0]
68
69def sexp_to_string(sexp):
70    """Convert a sexp, represented as nested lists containing strings,
71    into a single string of the form parseable by mesa.
72    """
73    if isinstance(sexp, basestring):
74        return sexp
75    assert isinstance(sexp, list)
76    result = ''
77    for s in sexp:
78        sub_result = sexp_to_string(s)
79        if result == '':
80            result = sub_result
81        elif '\n' not in result and '\n' not in sub_result and \
82                len(result) + len(sub_result) + 1 <= 70:
83            result += ' ' + sub_result
84        else:
85            result += '\n' + sub_result
86    return '({0})'.format(result.replace('\n', '\n '))
87
88def sort_decls(sexp):
89    """Sort all toplevel variable declarations in sexp.
90
91    This is used to work around the fact that
92    ir_reader::read_instructions reorders declarations.
93    """
94    assert isinstance(sexp, list)
95    decls = []
96    other_code = []
97    for s in sexp:
98        if isinstance(s, list) and len(s) >= 4 and s[0] == 'declare':
99            decls.append(s)
100        else:
101            other_code.append(s)
102    return sorted(decls) + other_code
103
104