diff options
Diffstat (limited to 'Tools/modulator/varsubst.py')
-rw-r--r-- | Tools/modulator/varsubst.py | 61 |
1 files changed, 61 insertions, 0 deletions
diff --git a/Tools/modulator/varsubst.py b/Tools/modulator/varsubst.py new file mode 100644 index 0000000..ec89fe3 --- /dev/null +++ b/Tools/modulator/varsubst.py @@ -0,0 +1,61 @@ +# +# Variable substitution. Variables are $delimited$ +# +import string +import regex +import regsub + +error = 'varsubst.error' + +class Varsubst: + def __init__(self, dict): + self.dict = dict + self.prog = regex.compile('\$[a-zA-Z0-9_]*\$') + self.do_useindent = 0 + + def useindent(self, onoff): + self.do_useindent = onoff + + def subst(self, str): + rv = '' + while 1: + pos = self.prog.search(str) + if pos < 0: + return rv + str + if pos: + rv = rv + str[:pos] + str = str[pos:] + len = self.prog.match(str) + if len == 2: + # Escaped dollar + rv = rv + '$' + str = str[2:] + continue + name = str[1:len-1] + str = str[len:] + if not self.dict.has_key(name): + raise error, 'No such variable: '+name + value = self.dict[name] + if self.do_useindent and '\n' in value: + value = self._modindent(value, rv) + rv = rv + value + + def _modindent(self, value, old): + lastnl = string.rfind(old, '\n', 0) + 1 + lastnl = len(old) - lastnl + sub = '\n' + (' '*lastnl) + return regsub.gsub('\n', sub, value) + +def _test(): + import sys + import os + + sys.stderr.write('-- Copying stdin to stdout with environment map --\n') + c = Varsubst(os.environ) + c.useindent(1) + d = sys.stdin.read() + sys.stdout.write(c.subst(d)) + sys.exit(1) + +if __name__ == '__main__': + _test() |