[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
humble proposal: New special form progn-1
From: |
Tino Calancha |
Subject: |
humble proposal: New special form progn-1 |
Date: |
Wed, 27 Jul 2016 21:16:28 +0900 (JST) |
User-agent: |
Alpine 2.20 (DEB 67 2015-01-07) |
Dear all,
i got this idea few days ago (see the patch at the end).
Even though I envision that no one here will like this proposal,
for me it's instructive to learn from your answers why this is
not a good idea.
So, why is this a bad idea?
Thanks in advance for your answer,
Tino
My (weak) motivation for introduce this is:
* Compact (and familiar) syntaxis.
* Same reasons to exists as prog2 has (excluding historical reasons).
* Other way to acomplish one usual task.
* Allow lower indentation level (see below):
(progn-1
(form1)
(form2)
(form3)
.
.
.
(formN-1)
(formN))
(prog1
(progn
(form1)
(form2)
(form3)
.
.
.
(formN-1))
(formN))
(prog2
(progn
(form1)
(form2)
(form3)
.
.
.
(formN-2))
(prog1
(formN-1)
(formN)))
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
From c9b38c42b253ca004c3aef4dd9dde274aa717d91 Mon Sep 17 00:00:00 2001
From: Tino Calancha <address@hidden>
Date: Wed, 27 Jul 2016 20:40:25 +0900
Subject: [PATCH] New special form progn-1
* src/eval.c (progn-1): Eval sequentially N forms and
return the value of the form N-1.
---
src/eval.c | 18 ++++++++++++++++++
1 file changed, 18 insertions(+)
diff --git a/src/eval.c b/src/eval.c
index 33b82f7..5eb0cfd 100644
--- a/src/eval.c
+++ b/src/eval.c
@@ -431,6 +431,23 @@ usage: (progn BODY...) */)
return val;
}
+DEFUN ("progn-1", Fprogn_1, Sprogn_1, 2, UNEVALLED, 0,
+ doc: /* Eval N forms sequentially; return value from form N-1.
+usage: (progn-1 FORM_1 FORM_2...FORM_N-1 FORM_N) */)
+ (Lisp_Object body)
+{
+ Lisp_Object val = Qnil;
+
+ while (CONSP (XCDR (body)))
+ {
+ val = eval_sub (XCAR (body));
+ body = XCDR (body);
+ }
+ eval_sub (XCAR (body));
+
+ return val;
+}
+
/* Evaluate BODY sequentially, discarding its value. Suitable for
record_unwind_protect. */
@@ -3906,6 +3923,7 @@ alist of active lexical bindings. */);
defsubr (&Sif);
defsubr (&Scond);
defsubr (&Sprogn);
+ defsubr (&Sprogn_1);
defsubr (&Sprog1);
defsubr (&Sprog2);
defsubr (&Ssetq);
--
2.8.1
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
In GNU Emacs 25.1.50.1 (x86_64-pc-linux-gnu, GTK+ Version 3.20.6)
of 2016-07-27 built
Repository revision: e0d425976e3a83585db9a586687897fe1ac6455f
- humble proposal: New special form progn-1,
Tino Calancha <=