From f4fbe4c986ed72c5a2f0c5b8228249d6ac89dd48 Mon Sep 17 00:00:00 2001
From: mainzelm <mainzelm>
Date: Tue, 18 Oct 2005 14:01:50 +0000
Subject: [PATCH] (rx (| numeric alphabetic)) yields a char-set: but (rx (|
 ,(rx numeric) ,(rx alphabetic))) doesn't:, even though the "type-checking
 rules" for char-sets says that it should:

> (rx (| numeric alphabetic))
'#{re-char-set}
> (rx (| ,(rx numeric) ,(rx alphabetic)))
'#{Re-choice}

The following patch fixes this but I'm not sure if
make-re-choice is the right place to tackle this problem:

This fixes bug report #1063781
---
 scsh/rx/re.scm | 18 ++++++++++--------
 1 file changed, 10 insertions(+), 8 deletions(-)

diff --git a/scsh/rx/re.scm b/scsh/rx/re.scm
index b06227e..eef6633 100644
--- a/scsh/rx/re.scm
+++ b/scsh/rx/re.scm
@@ -133,14 +133,16 @@
   (really-make-re-choice elts tsm (new-cre posix-str tvec)))
 
 (define (make-re-choice res)
-  (make-re-choice/tsm res
-		      (fold (lambda (re sm-count)
-			   (let ((maybe-tsm (re-tsm re)))
-			     (if (and (number? maybe-tsm)
-				      (number? sm-count))
-				 (+ maybe-tsm sm-count)
-				 (unspecific))))
-			    0 res)))
+  (if (every re-char-set? res)
+      (make-re-char-set (apply char-set-union (map re-char-set:cset res)))
+      (make-re-choice/tsm res
+                          (fold (lambda (re sm-count)
+                                  (let ((maybe-tsm (re-tsm re)))
+                                    (if (and (number? maybe-tsm)
+                                             (number? sm-count))
+                                        (+ maybe-tsm sm-count)
+                                        (unspecific))))
+                                0 res))))
 
 ;;; Slightly smart choice constructor:
 ;;; - Flattens nested choices