sxml-match example from manual fails

sxml-match example from manual fails

[Aidan Gauland]

I'm trying to figure out how to use sxml-match, so I tried an example
from the Guile manual:
https://www.gnu.org/software/guile/manual/html_node/sxml_002dmatch.html

"The example below illustrates the pattern matching of an XML element:

     (sxml-match '(e (@ (i 1)) 3 4 5)
       [(e (@ (i ,d)) ,a ,b ,c) (list d a b c)]
       [,otherwise #f])

Each clause in sxml-match contains two parts: a pattern and one or more
expressions which are evaluated if the pattern is successfully match.
The example above matches an element e with an attribute i and three
children."

But guile doesn't seem to like it:
$ guile
GNU Guile 2.0.5-deb+1-3
[...]
scheme@(guile-user)> (sxml-match '(e (@ (i 1)) 3 4 5) [(e (@ (i ,d)) ,a
,b ,c) (list d a b c)] [,otherwise #f])
While compiling expression:
ERROR: Syntax error:
unknown file:1:0: source expression failed to match any pattern in form
(@ (i (unquote d)))

So, can someone tell me whether there's an error in the manual?

Regards,
Aidan Gauland

Re: sxml-match example from manual fails

[Keith Wright]

> I'm trying to figure out how to use sxml-match, so I tried an example
> from the Guile manual:
> https://www.gnu.org/software/guile/manual/html_node/sxml_002dmatch.html
> 
> "The example below illustrates the pattern matching of an XML element:
> 
>      (sxml-match '(e (@ (i 1)) 3 4 5)
>        [(e (@ (i ,d)) ,a ,b ,c) (list d a b c)]
>        [,otherwise #f])
> 
> So, can someone tell me whether there's an error in the manual?

I don't have the manual handy, but surely that
should be a backquote "`" rather than a quote "'".

That is change:

>      (sxml-match '(e (@ (i 1)) 3 4 5)

to

>      (sxml-match `(e (@ (i 1)) 3 4 5)

-- 
     -- Keith Wright  <kwright@free-comp-shop.com>

Programmer in Chief, Free Computer Shop <http://www.free-comp-shop.com>
         ---  Food, Shelter, Source code.  ---

Re: sxml-match example from manual fails

[Ludovic Courtès]

Hi,

Aidan Gauland <aidalgol@no8wireless.co.nz> skribis:

> But guile doesn't seem to like it:
> $ guile
> GNU Guile 2.0.5-deb+1-3
> [...]
> scheme@(guile-user)> (sxml-match '(e (@ (i 1)) 3 4 5) [(e (@ (i ,d)) ,a
> ,b ,c) (list d a b c)] [,otherwise #f])
> While compiling expression:
> ERROR: Syntax error:
> unknown file:1:0: source expression failed to match any pattern in form
> (@ (i (unquote d)))

You need to import the module first:

  scheme@(guile-user)> (use-modules(sxml match))
  scheme@(guile-user)>      (sxml-match '(e (@ (i 1)) 3 4 5)
         [(e (@ (i ,d)) ,a ,b ,c) (list d a b c)]
         [,otherwise #f])
  $2 = (1 3 4 5)

Thanks,
Ludo’.