util: add an interpolate() function to for replacing multiple values
util.interpolate can be used to replace multiple items in a string all at once
(and optionally apply a function to the replacement), without worrying about
recursing:
>>> import util
>>> s = '$foo, $spam'
>>> util.interpolate(r'\$', { 'foo': 'bar', 'spam': 'eggs' }, s)
'bar, eggs'
>>> util.interpolate(r'\$', { 'foo': 'spam', 'spam': 'foo' }, s)
'spam, foo'
>>> util.interpolate(r'\$', { 'foo': 'spam', 'spam': 'foo' }, s, lambda s: s.upper())
'SPAM, FOO'
The patch also changes filemerge.py to use this new function.
--- a/mercurial/filemerge.py Thu Aug 19 11:14:09 2010 -0500
+++ b/mercurial/filemerge.py Wed Aug 18 18:18:26 2010 -0400
@@ -222,8 +222,8 @@
if "$output" in args:
out, a = a, back # read input from backup, write to original
replace = dict(local=a, base=b, other=c, output=out)
- args = re.sub("\$(local|base|other|output)",
- lambda x: '"%s"' % util.localpath(replace[x.group()[1:]]), args)
+ args = util.interpolate(r'\$', replace, args,
+ lambda s: '"%s"' % util.localpath(s))
r = util.system(toolpath + ' ' + args, cwd=repo.root, environ=env)
if not r and (_toolbool(ui, tool, "checkconflicts") or
--- a/mercurial/util.py Thu Aug 19 11:14:09 2010 -0500
+++ b/mercurial/util.py Wed Aug 18 18:18:26 2010 -0400
@@ -1408,3 +1408,18 @@
except ValueError:
pass
return termwidth_()
+
+def interpolate(prefix, mapping, s, fn=None):
+ """Return the result of interpolating items in the mapping into string s.
+
+ prefix is a single character string, or a two character string with
+ a backslash as the first character if the prefix needs to be escaped in
+ a regular expression.
+
+ fn is an optional function that will be applied to the replacement text
+ just before replacement.
+ """
+ fn = fn or (lambda s: s)
+ r = re.compile(r'%s(%s)' % (prefix, '|'.join(mapping.keys())))
+ return r.sub(lambda x: fn(mapping[x.group()[1:]]), s)
+