On Sun, May 12, 2013 at 10:49:09PM +0200, Felix wrote:
> Attached are some patches for adding two small enhancements:
>
> 1) "require-extension-for-syntax"/"use-for-syntax", which does
> the same as the often occurring idiom
>
> (begin-for-syntax (require-library FOO))
> (import-for-syntax FOO)
>
> So this loads an extension and imports it, but at expansion time.
I had a chance to look at it just now. There's a small problem with the
generated import libraries:
$ cat foo.scm
(module foo (foo)
(import chicken scheme)
(use-for-syntax srfi-1)
(define-syntax foo
(er-macro-transformer
(lambda (e r c) `(,(r 'list) ,@(iota 5))))))
$ csc -s foo.scm -j foo
$ csi
#;1> (use foo)
; loading ./foo.import.scm ...
; loading /home/sjamaan/chicken-test/lib/chicken/7/chicken.import.so ...
; loading /home/sjamaan/chicken-test/lib/chicken/7/srfi-1.import.so ...
; loading ./foo.so ...
Note: the following toplevel variables are referenced but unbound:
iota
#;2>
The attached patch fixes this by expanding to require-for-syntax instead
of loading the module at compilation time and expanding only to import.
Cheers,
Peter
--
http://www.more-magic.net
>From e3a8a14a95980f8607ada49dc78ed10b9d85410b Mon Sep 17 00:00:00 2001
From: felix <fe...@call-with-current-continuation.org>
Date: Sun, 12 May 2013 22:36:39 +0200
Subject: [PATCH] Add "require-extension-for-syntax"
A more intuitive form of the often occurring idiom
(begin-for-syntax (require-library ...))
(import-for-syntax ...)
For consistency and as a slightly shorter variant, "use-for-syntax"
is also provided as an alias.
Signed-off-by: Peter Bex <peter....@xs4all.nl>
---
NEWS | 3 +++
chicken-syntax.scm | 7 +++++++
eval.scm | 1 +
expand.scm | 7 +++++++
manual/Non-standard macros and special forms | 20 ++++++++++++++++++--
5 files changed, 36 insertions(+), 2 deletions(-)
diff --git a/NEWS b/NEWS
index be9d098..585ea55 100644
--- a/NEWS
+++ b/NEWS
@@ -26,6 +26,9 @@
inlining could lead to non-termination of the compiler (thanks to
Andrei Barbu).
+- Syntax expander
+ - added "require-extension-for-syntax" and "use-for-syntax".
+
- Core libraries
- read-line no longer returns trailing CRs in rare cases on TCP ports (#568)
- write and pp now correctly use escape sequences for control characters
diff --git a/chicken-syntax.scm b/chicken-syntax.scm
index 9b3e91d..06570db 100644
--- a/chicken-syntax.scm
+++ b/chicken-syntax.scm
@@ -1082,6 +1082,13 @@
(##sys#check-syntax 'use x '(_ . #(_ 0)))
`(##core#require-extension ,(cdr x) #t))))
+(##sys#extend-macro-environment
+ 'use-for-syntax '()
+ (##sys#er-transformer
+ (lambda (x r c)
+ (##sys#check-syntax 'use-for-syntax x '(_ . #(_ 0)))
+ `(,(r 'require-extension-for-syntax) ,@(cdr x)))))
+
;;; compiler syntax
diff --git a/eval.scm b/eval.scm
index 62227cd..963dd20 100644
--- a/eval.scm
+++ b/eval.scm
@@ -1410,6 +1410,7 @@
(if (memq (car s)
'(import
require-extension
+ require-extension-for-syntax
require-library
begin-for-syntax
export
diff --git a/expand.scm b/expand.scm
index b278ec0..4b69c1d 100644
--- a/expand.scm
+++ b/expand.scm
@@ -1372,6 +1372,13 @@
`(##core#require-extension ,ids #t) ) ) ) )
(##sys#extend-macro-environment
+ 'require-extension-for-syntax
+ '()
+ (##sys#er-transformer
+ (lambda (x r c)
+ `(,(r 'begin-for-syntax) (,(r 'require-extension) ,@(cdr x))))))
+
+(##sys#extend-macro-environment
'module
'()
(##sys#er-transformer
diff --git a/manual/Non-standard macros and special forms b/manual/Non-standard
macros and special forms
index c686554..ee22283 100644
--- a/manual/Non-standard macros and special forms
+++ b/manual/Non-standard macros and special forms
@@ -43,8 +43,6 @@ defined:
* {{(srfi NUMBER ...)}} is required for SRFI-55 compatibility and is fully
implemented
* {{(version ID NUMBER)}} is equivalent to {{ID}}, but checks at compile-time
whether the extension named {{ID}} is installed and whether its version is
equal or higher than {{NUMBER}}. {{NUMBER}} may be a string or a number, the
comparison is done lexicographically (using {{string>=?}}).
-See also: {{set-extension-specifier!}}
-
==== require-extension
<macro>(require-extension ID ...)</macro>
@@ -62,6 +60,24 @@ This implementation of {{require-extension}} is compliant
with [[http://srfi.sch
{{use}} is just a shorter alias for {{require-extension}}.
+==== require-extension-for-syntax
+
+<macro>(require-extension-for-syntax ID ...)</macro>
+
+An abbreviation for the idiom:
+
+<enscript highlight=scheme>
+(begin-for-syntax (require-library ID ...)) ; load extension at expansion-time
+(import-for-syntax ID ...) ; import extension for use in
syntax-transformers
+</enscript>
+
+
+==== use-for-syntax
+
+<macro>(use-for-syntax ID ...)</macro>
+
+{{use}} is just a shorter alias for {{require-extension-for-syntax}} (which is
quite a mouthful).
+
=== Binding forms for optional arguments
--
1.8.0.1
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