each-match macro family: missing anon block.

* txr.1: Adding the missing requirement that each-match
and the other macros in that family must have an implicit
anonymous block around the body forms. This is a requirements
bug, effectively: the programmer expects these operators to be
consistent with the each operator, as part of the same family.

* match.tl (each-match-expander): Implement the requirement.
Since we are using mapping functions, we must use temporary
variables: the evaluation of the expressions which produce the
sequence argument values to the mapping functions must be
outside of the anonymous block. The block must surround only
the function call.

* tests/011/patmatch.tl: Add small test case covering this.

1 files changed, 5 insertions, 2 deletions

diff --git a/stdlib/match.tl b/stdlib/match.tl
index 8d014f11..a38798d6 100644
--- a/stdlib/match.tl
+++ b/stdlib/match.tl
@@ -1070,8 +1070,11 @@
                    (eql 2 (length pair)))
         (compile-error f "invalid pattern-sequence pair ~s" pair)))
     (let* ((pats [mapcar car pat-seq-pairs])
-           (seqs [mapcar cadr pat-seq-pairs]))
-       ^(,fun (lambda-match ((,*pats) (progn ,*body))) ,*seqs))))
+           (seqs [mapcar cadr pat-seq-pairs])
+           (gens [mapcar (ret (gensym)) pat-seq-pairs]))
+       ^(let ,(zip gens seqs)
+          (block nil
+            (,fun (lambda-match ((,*pats) (progn ,*body))) ,*gens))))))
 
 (defmacro each-match (:form f pat-seq-pairs . body)
   (each-match-expander f pat-seq-pairs body 'mapdo))