Make LET-MATCH/IF-MATCH conform to documentation & comments.

In the process, rewrite LET-MATCH as a SYNTAX-RULES macro.

scsh/rx/re-match-syntax.scm

@@ -11,34 +11,18 @@
 ;;; of blowing up, we execute the ALT form instead.
 
 (define-syntax let-match
-  (lambda (exp r c)
-    (if (< (length exp) 3)
-	(error "No match-vars list in LET-MATCH" exp))
-    (let ((m (cadr exp))		; The match expression
-	  (mvars (caddr exp))		; The match vars
-	  (body (cdddr exp))		; The expression's body forms
+  (syntax-rules ()
+    ((let-match ?match-exp (?mvars ...) ?body0 ?body ...)
+     (let ((?match-var ?match-exp))
+       (let-match-aux ?match-var 0 (?mvars ...) ?body0 ?body ...)))))
 
-	  (%begin           (r 'begin))
-	  (%match:substring (r 'match:substring))
-	  (%let*            (r 'let*)))
-
-      (cond ((null? mvars) `(,%begin ,@body))
-
-	    ((pair? mvars)
-	     (let* ((msv (or (car mvars) (r 'match-val))) ; "match-struct var"
-		    (sm-bindings (let recur ((i 0) (vars (cdr mvars)))
-				   (if (pair? vars)
-				       (let ((var (car vars))
-					     (bindings (recur (+ i 1) (cdr vars))))
-					 (if var
-					     (cons `(,var (,%match:substring ,msv ,i))
-						   bindings)
-					     bindings))
-				       '()))))
-	       `(,%let* ((,msv ,m) ,@sm-bindings) ,@body)))
-
-
-	    (else (error "Illegal match-vars list in LET-MATCH" mvars exp))))))
+(define-syntax let-match-aux
+  (syntax-rules ()
+    ((let-match-aux ?match-var ?i0 (?mvar0 ?mvars ...) ?body0 ?body ...)
+     (let ((?mvar0 (match:substring ?match-var ?i0)))
+       (let-match-aux ?match-var (+ 1 ?i0) (?mvars ...) ?body0 ?body ...)))
+    ((let-match-aux ?match-var ?i0 () ?body0 ?body ...)
+     (begin ?body0 ?body ...))))
 
 (define-syntax if-match
   (syntax-rules ()