Mercurial > repos > davidmurphy > codonlogo
view corebio/_future/_string.py @ 9:f3462128e87c
Minor alterations to the galaxy interface with some better examples and error messages added.
author | davidmurphy |
---|---|
date | Mon, 30 Jan 2012 08:17:57 -0500 |
parents | c55bdc2fb9fa |
children |
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#################################################################### import re as _re class _multimap: """Helper class for combining multiple mappings. Used by .{safe_,}substitute() to combine the mapping and keyword arguments. """ def __init__(self, primary, secondary): self._primary = primary self._secondary = secondary def __getitem__(self, key): try: return self._primary[key] except KeyError: return self._secondary[key] class _TemplateMetaclass(type): pattern = r""" %(delim)s(?: (?P<escaped>%(delim)s) | # Escape sequence of two delimiters (?P<named>%(id)s) | # delimiter and a Python identifier {(?P<braced>%(id)s)} | # delimiter and a braced identifier (?P<invalid>) # Other ill-formed delimiter exprs ) """ def __init__(cls, name, bases, dct): super(_TemplateMetaclass, cls).__init__(name, bases, dct) if 'pattern' in dct: pattern = cls.pattern else: pattern = _TemplateMetaclass.pattern % { 'delim' : _re.escape(cls.delimiter), 'id' : cls.idpattern, } cls.pattern = _re.compile(pattern, _re.IGNORECASE | _re.VERBOSE) class Template: """A string class for supporting $-substitutions.""" __metaclass__ = _TemplateMetaclass delimiter = '$' idpattern = r'[_a-z][_a-z0-9]*' def __init__(self, template): self.template = template # Search for $$, $identifier, ${identifier}, and any bare $'s def _invalid(self, mo): i = mo.start('invalid') lines = self.template[:i].splitlines(True) if not lines: colno = 1 lineno = 1 else: colno = i - len(''.join(lines[:-1])) lineno = len(lines) raise ValueError('Invalid placeholder in string: line %d, col %d' % (lineno, colno)) def substitute(self, *args, **kws): if len(args) > 1: raise TypeError('Too many positional arguments') if not args: mapping = kws elif kws: mapping = _multimap(kws, args[0]) else: mapping = args[0] # Helper function for .sub() def convert(mo): # Check the most common path first. named = mo.group('named') or mo.group('braced') if named is not None: val = mapping[named] # We use this idiom instead of str() because the latter will # fail if val is a Unicode containing non-ASCII characters. return '%s' % val if mo.group('escaped') is not None: return self.delimiter if mo.group('invalid') is not None: self._invalid(mo) raise ValueError('Unrecognized named group in pattern', self.pattern) return self.pattern.sub(convert, self.template) def safe_substitute(self, *args, **kws): if len(args) > 1: raise TypeError('Too many positional arguments') if not args: mapping = kws elif kws: mapping = _multimap(kws, args[0]) else: mapping = args[0] # Helper function for .sub() def convert(mo): named = mo.group('named') if named is not None: try: # We use this idiom instead of str() because the latter # will fail if val is a Unicode containing non-ASCII return '%s' % mapping[named] except KeyError: return self.delimiter + named braced = mo.group('braced') if braced is not None: try: return '%s' % mapping[braced] except KeyError: return self.delimiter + '{' + braced + '}' if mo.group('escaped') is not None: return self.delimiter if mo.group('invalid') is not None: return self.delimiter raise ValueError('Unrecognized named group in pattern', self.pattern) return self.pattern.sub(convert, self.template)