revset nit: "sort spec must be a string"

[Matt Mackall]

On Wed, 2010-06-30 at 15:29 -0400, Greg Ward wrote:
> On Wed, Jun 30, 2010 at 3:14 PM, Greg Ward <greg at gerg.ca> wrote:
> > I was just playing around with revsets a bit and noticed an annoyance
> > with sort():
> >
> >  $ hg log -r "sort(descendants(qparent), -rev)"
> >  hg: parse error: sort spec must be a string
> [...]
> > but that's a bit awkward.  Since sort keys are hardcoded strings of
> > lowercase letters, I don't see any theoretical reason why quoting is
> > required to protect the "-".  Should I try to cook up a patch?
> 
> Oh, I see.  I just read the code and saw that my question is nonsense.
>  It could only work if sort keys were keywords in the language rather
> than ordinary string tokens.  Never mind...

Actually, it can be fixed. Negate is normally only used for revision ids
like '-3'. But negating any string or symbol should result in a string
prefixed with a minus sign. I've fixed it:

$ hg debugrevspec --debug 'sort(descendants(qparent), -rev)'
('func', ('symbol', 'sort'), ('list', ('func', ('symbol',
'descendants'), ('symbol', 'qparent')), ('negate', ('symbol', 'rev'))))
11466
11465

There are a couple approach here: either teach getstring() about negate
nodes or teach the optimizer to turn a negate node into a negated
string. Here's the latter:

diff -r ad27428c59ce mercurial/revset.py
--- a/mercurial/revset.py	Wed Jun 30 17:34:20 2010 -0500
+++ b/mercurial/revset.py	Wed Jun 30 17:39:19 2010 -0500
@@ -111,10 +111,6 @@
 
 # operator methods
 
-def negate(repo, subset, x):
-    return getset(repo, subset,
-                  ('string', '-' + getstring(x, _("can't negate that"))))
-
 def stringset(repo, subset, x):
     x = repo[x].rev()
     if x == -1 and len(subset) == len(repo):
@@ -482,7 +478,6 @@
 }
 
 methods = {
-    "negate": negate,
     "range": rangeset,
     "string": stringset,
     "symbol": symbolset,
@@ -515,6 +510,9 @@
         return optimize(('range', ('string', '0'), x[1]), small)
     elif op == 'rangepost':
         return optimize(('range', x[1], ('string', 'tip')), small)
+    elif op == 'negate':
+        return optimize(('string',
+                         '-' + getstring(x[1], _("can't negate that"))), small)
     elif op in 'string symbol negate':
         return smallbonus, x # single revisions are small
     elif op == 'and' or op == 'dagrange':



-- 
Mathematics is the supreme nostalgia of our time.