matcher: allow omitted variabel in predicates

For instance @(oddp) instead of @(oddp x) to require an
element to satisfy oddp without capturing it to a variable.

* share/txr/stdlib/match.tl (compile-predicate-match): Make
the symbolic argument optional, defaulting to nil.
A nil symbol is already treated as pseudo-variable which
consumes an item without binding to a variable.

1 files changed, 1 insertions, 1 deletions

diff --git a/share/txr/stdlib/match.tl b/share/txr/stdlib/match.tl
index 526e3b3d..18ab6577 100644
--- a/share/txr/stdlib/match.tl
+++ b/share/txr/stdlib/match.tl
@@ -116,7 +116,7 @@
             test-expr ^(equal ,obj-var ',atom)))))
 
 (defun compile-predicate-match (pred-expr obj-var)
-  (tree-bind (fun sym) pred-expr
+  (tree-bind (fun : sym) pred-expr
     (or (null sym) (bindable sym)
         (compile-error *match-form* "~s is not a symbol" sym))
     (let ((var-match (compile-var-match sym obj-var)))