From 2e1a18eb896cdbeb278b545576d1ef100bdea12b Mon Sep 17 00:00:00 2001
From: Kaz Kylheku <kaz@kylheku.com>
Date: Thu, 14 Nov 2013 15:01:40 -0800
Subject: TAILPROG: renamed to TLET, loses the variable bindings parameter.
 Variables are automatically collected from the labels.

---
 tail-recursion.lisp | 27 +++++++++++++++------------
 1 file changed, 15 insertions(+), 12 deletions(-)

(limited to 'tail-recursion.lisp')

diff --git a/tail-recursion.lisp b/tail-recursion.lisp
index 9bdf0b3..b963d49 100644
--- a/tail-recursion.lisp
+++ b/tail-recursion.lisp
@@ -1,6 +1,6 @@
 ;;;
-;;; ARGTAGS, TAILPROG and DEFTAIL
-;;; Copyright 2012 Kaz Kylheku
+;;; ARGTAGS, TLET and DEFTAIL
+;;; Copyright 2013 Kaz Kylheku
 ;;; <kaz@kylheku.com>
 ;;;
 ;;; This Lisp source contains three ideas which reveal tail recursion
@@ -8,7 +8,7 @@
 ;;; which disguise goto behind a more disciplined interface
 ;;; which resembles function calling.
 ;;;
-;;; First ARGTAGS is presented. Then a macro called TAILPROG which
+;;; First ARGTAGS is presented. Then a macro called TLET which
 ;;; builds a slightly higher level abstraction on ARGTAGS.
 ;;;
 ;;; Finally a scheme, no pun intended, for cross-module tail calling
@@ -142,10 +142,11 @@
 
 
 ;;;
-;;; TAILPROG
-;;; ========
-;;;
-;;; (Thanks to Klaus Harbo for some fixes).
+;;; TLET
+;;; ====
+;;; 
+;;; (Thanks to Klaus Harbo for some fixes. to the original version
+;;; which was called TAILPROG).
 ;;;
 ;;; This macro provides wraps more syntactic sugar around ARGTAGS,
 ;;; giving rise to a syntax which resembles the Lisp LABELS.
@@ -158,15 +159,17 @@
 ;;; the value of such a call, it still does not return.
 ;;;;
 
-(defmacro tailprog (let-bindings pseudo-funcs &rest forms)
-   (let (argtags-forms macrolet-elems)
+(defmacro tlet (pseudo-funcs &rest forms)
+   (let (argtags-forms macrolet-elems var-list)
      (dolist (pfunc pseudo-funcs)
        (destructuring-bind (name vars &rest forms) pfunc
          (push `(label ,name ,@vars) argtags-forms)
          (push `(return (progn ,@forms)) argtags-forms)
-         (push `(,name (&rest args) `(goto ,',name ,@args)) macrolet-elems)))
+         (push `(,name (&rest args) `(goto ,',name ,@args)) macrolet-elems)
+         (dolist (var vars)
+           (push var var-list))))
      `(macrolet ,(reverse macrolet-elems)
-        (let ,let-bindings
+        (let ,var-list
           (argtags nil
                    (return (progn ,@forms))
                    ,@(reverse argtags-forms))))))
@@ -231,7 +234,7 @@
 ;;; 
 ;;; This is still a GOTO-like abstraction, because tail calls are tail
 ;;; calls even if they are not in a tail position. They never return,
-;;; just like in TAILPROG.
+;;; just like in TLET.
 ;;;
 
 (defvar *tail-escape* nil)
-- 
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