3 The syntax of a source list file is a very small subset of GNU Make. These
8 non-nested variable expansion
11 The goal is to allow Makefile's and SConscript's to share source listing.
14 class SourceListParser(object):
16 self.symbol_table = {}
19 def _reset(self, filename=None):
20 self.filename = filename
25 def _error(self, msg):
26 raise RuntimeError('%s:%d: %s' % (self.filename, self.line_no, msg))
28 def _next_dereference(self, val, cur):
29 """Locate the next $(...) in value."""
30 deref_pos = val.find('$', cur)
33 elif val[deref_pos + 1] != '(':
34 self._error('non-variable dereference')
36 deref_end = val.find(')', deref_pos + 2)
38 self._error('unterminated variable dereference')
40 return (deref_pos, deref_end + 1)
42 def _expand_value(self, val):
43 """Perform variable expansion."""
47 deref_pos, deref_end = self._next_dereference(val, cur)
52 sym = val[(deref_pos + 2):(deref_end - 1)]
53 expanded += val[cur:deref_pos] + self.symbol_table[sym]
58 def _parse_definition(self, line):
59 """Parse a variable definition line."""
60 op_pos = line.find('=')
63 self._error('not a variable definition')
66 if line[op_pos - 1] in [':', '+', '?']:
69 self._error('only =, :=, and += are supported')
71 # set op, sym, and val
72 op = line[op_pos:op_end]
73 sym = line[:op_pos].strip()
74 val = self._expand_value(line[op_end:].lstrip())
77 self.symbol_table[sym] = val
79 self.symbol_table[sym] += ' ' + val
81 if sym not in self.symbol_table:
82 self.symbol_table[sym] = val
84 def _parse_line(self, line):
85 """Parse a source list line."""
87 if line and line[-1] == '\\':
88 # spaces around "\\\n" are replaced by a single space
90 self.line_cont += line[:-1].strip() + ' '
92 self.line_cont = line[:-1].rstrip() + ' '
95 # combine with previous lines
97 line = self.line_cont + line.lstrip()
101 begins_with_tab = (line[0] == '\t')
106 self._error('recipe line not supported')
108 self._parse_definition(line)
112 def parse(self, filename):
113 """Parse a source list file."""
114 if self.filename != filename:
116 lines = fp.read().splitlines()
120 self._reset(filename)
122 self.line_no += self._parse_line(line)
127 return self.symbol_table
129 def add_symbol(self, name, value):
130 self.symbol_table[name] = value