Hello,
What would be the definition of a reader macro function for
character that just returns the character as a normal constituant
character? In the example below, I want '{abc to still evaluate to {ABC
CL-USER 10 > (get-macro-character #\{)
NIL
NIL
CL-USER 11 > '{abc
{ABC
CL-USER 12 > (set-macro-character #\{ (lambda (stream char) char))
T
CL-USER 13 > '{
#\{
CL-USER 14 > abc
Error: The variable ABC is unbound.
Francis
Unable to parse email body. Email id is 6988
Francis Leboutte wrote:
> What would be the definition of a reader macro function for
> character that just returns the character as a normal constituant
> character? In the example below, I want '{abc to still evaluate to {ABC
>
>
> CL-USER 10 > (get-macro-character #\{)
> NIL
> NIL
>
> CL-USER 11 > '{abc
> {ABC
>
> CL-USER 12 > (set-macro-character #\{ (lambda (stream char) char))
> T
I think that adding a call to SET-SYNTAX-FROM-CHAR, e.g.
(set-syntax-from-char #\{ #\A)
should do what you need.
Arthur Lemmens
Le 25/09/2007 11:10, Nick Levine écrivait :
> What would be the definition of a reader macro function for
> character that just returns the character as a normal constituant
> character? In the example below, I want '{abc to still evaluate to
> {ABC
>
>Careful. I don't think you really mean "evaluate". "Read as", maybe?
This is what I mean:
USER 8 > '{ab
{ab
USER 9 > '{
{
>So ignoring (which you shouldn't) what happens if the #\{ is not
>followed by a symbol, or how you'd get to a symbol not visible in
>*package*, consider:
>
>(lambda (stream char) (intern (format nil "~c~a" char (read stream t nil t))))
This looks promising. But see my next post.
Thanks,
Francis
>- nick
>
>
> CL-USER 10 > (get-macro-character #\{)
> NIL
> NIL
>
> CL-USER 11 > '{abc
> {ABC
>
> CL-USER 12 > (set-macro-character #\{ (lambda (stream char) char))
> T
>
> CL-USER 13 > '{
> #\{
>
> CL-USER 14 > abc
>
> Error: The variable ABC is unbound.
>
>
>
> Francis
Le 25/09/2007 11:20, Arthur Lemmens écrivait :
>Francis Leboutte wrote:
>
> > What would be the definition of a reader macro function for
> > character that just returns the character as a normal constituant
> > character? In the example below, I want '{abc to still evaluate to {ABC
> >
> >
> > CL-USER 10 > (get-macro-character #\{)
> > NIL
> > NIL
> >
> > CL-USER 11 > '{abc
> > {ABC
> >
> > CL-USER 12 > (set-macro-character #\{ (lambda (stream char) char))
> > T
>
>I think that adding a call to SET-SYNTAX-FROM-CHAR, e.g.
>
> (set-syntax-from-char #\{ #\A)
>
>should do what you need.
I want to write something a bit more dynamic like this:
(set-macro-character
#\{
(lambda (stream char)
(cond (*rm-fun (funcall *rm-fun stream char))
(T
;; takes char as a constituant character
...
))))
In a Lisp implementation where a constituant
character would have a reader macro function, the answer would be simple:
(set-macro-character
#\{
(lambda (stream char)
(cond (*rm-fun (funcall *rm-fun stream char))
(T
(funcall (get-macro-character #\a) stream char)
))))
Francis
>Arthur Lemmens