ref: 8150f689959f71410f56ab66c0e89698c58459bc
dir: /sys/src/cmd/python/Tools/modulator/varsubst.py/
# # Variable substitution. Variables are $delimited$ # import re error = 'varsubst.error' class Varsubst: def __init__(self, dict): self.dict = dict self.prog = re.compile('\$([a-zA-Z0-9_]*)\$') self.do_useindent = 0 def useindent(self, onoff): self.do_useindent = onoff def subst(self, s): rv = '' while 1: m = self.prog.search(s) if not m: return rv + s rv = rv + s[:m.start()] s = s[m.end():] if m.end() - m.start() == 2: # Escaped dollar rv = rv + '$' s = s[2:] continue name = m.group(1) 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 = old.rfind('\n', 0) + 1 lastnl = len(old) - lastnl sub = '\n' + (' '*lastnl) return re.sub('\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()