templater: add function to help substituting patterns in template string
This will be used to rewrite a filename pattern to a template string.
--- a/mercurial/templater.py Sun Jan 07 11:04:53 2018 +0900
+++ b/mercurial/templater.py Sun Jan 07 11:21:25 2018 +0900
@@ -172,6 +172,26 @@
raise error.ProgrammingError('unexpected type: %s' % typ)
raise error.ProgrammingError('unterminated scanning of template')
+def scantemplate(tmpl):
+ """Scan (type, start, end) positions of outermost elements in template
+
+ >>> list(scantemplate(b'foo{bar}"baz'))
+ [('string', 0, 3), ('template', 3, 8), ('string', 8, 12)]
+ >>> list(scantemplate(b'outer{"inner"}outer'))
+ [('string', 0, 5), ('template', 5, 14), ('string', 14, 19)]
+ >>> list(scantemplate(b'foo\\{escaped}'))
+ [('string', 0, 5), ('string', 5, 13)]
+ """
+ last = None
+ for typ, val, pos in _scantemplate(tmpl, 0, len(tmpl)):
+ if last:
+ yield last + (pos,)
+ if typ == 'end':
+ return
+ else:
+ last = (typ, pos)
+ raise error.ProgrammingError('unterminated scanning of template')
+
def _scantemplate(tmpl, start, stop, quote=''):
"""Parse template string into chunks of strings and template expressions"""
sepchars = '{' + quote