Re: small JSON encoder improvement

Shiro Kawai <[email protected]> Fri, 8 Nov 2024 00:53:40 -1000
Newsgroups gmane.lisp.scheme.gauche
Message-ID <CALN0JNFiiR_4bSHwtTScobwYPaWt7nrG=JiYqJc6sq_YNMyLXg@mail.gmail.com>
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Thanks.  Patch applied.



On Thu, Nov 7, 2024 at 9:17=E2=80=AFPM Jens Thiele <[email protected]> wrote:

> Shiro Kawai <[email protected]> writes:
>
> > Oops, there was a reason we used `fold` in `print-object`.   A dictiona=
ry
> > can be passed, which is traversable but not necessarily orderable, i.e.
> > `for-each-with-index` can't be used.
>
> Ah sorry, missed that. Fixed it in the spirit of print-instance:
>
> diff --git a/lib/rfc/json.scm b/lib/rfc/json.scm
> index 73fd021ab..a8fdd7612 100644
> --- a/lib/rfc/json.scm
> +++ b/lib/rfc/json.scm
> @@ -245,44 +245,46 @@
>                       "can't convert Scheme object to json:" obj)]))
>
>  (define (print-object obj)
> -  (display "{")
> -  (fold (^[attr comma]
> +  (write-char #\{)
> +  (fold (^[attr comma-needed?]
>            (unless (pair? attr)
>              (error <json-construct-error> :object obj
>                     "construct-json needs an assoc list or dictionary, \
>                      but got:" obj))
> -          (display comma)
> +          (when comma-needed?
> +            (write-char #\,))
>            (print-string (x->string (car attr)))
> -          (display ":")
> +          (write-char #\:)
>            (print-value (cdr attr))
> -          ",")
> -        "" obj)
> -  (display "}"))
> +          #t)
> +        #f obj)
> +  (write-char #\}))
>
>  (define (print-array obj)
> -  (display "[")
> +  (write-char #\[)
>    (for-each-with-index (^[i val]
> -                         (unless (zero? i) (display ","))
> +                         (unless (zero? i) (write-char #\,))
>                           (print-value val))
> -                       obj)
> -  (display "]"))
> +                      obj)
> +  (write-char #\]))
>
>  (define (print-instance obj)            ;<json-mixin>
>    (let1 class (class-of obj)
> -    (display "{")
> -    (fold (^[slot comma]
> +    (write-char #\{)
> +    (fold (^[slot comma-needed?]
>              (if-let1 json-name (slot-definition-option slot :json-name #=
f)
>                (begin
> -                (display comma)
> +                (when comma-needed?
> +                  (write-char #\,))
>                  (print-string (if (eqv? json-name #t)
>                                  (x->string (slot-definition-name slot))
>                                  (x->string json-name)))
> -                (display ":")
> +                (write-char #\:)
>                  (print-value (slot-ref obj (slot-definition-name slot)))
> -                ",")
> -              comma))
> -          "" (class-slots class))
> -    (display "}")))
> +                #t)
> +              comma-needed?))
> +          #f (class-slots class))
> +    (write-char #\})))
>
>  (define (print-number num)
>    (cond [(or (not (real? num)) (not (finite? num)))
> @@ -307,9 +309,9 @@
>               (if (>=3D code #x10000)
>                 (for-each hexescape (ucs4->utf16 code))
>                 (hexescape code)))]))
> -  (display "\"")
> +  (write-char #\")
>    (string-for-each print-char str)
> -  (display "\""))
> +  (write-char #\"))
>
>  (define (construct-json x :optional (oport (current-output-port)))
>    (with-output-to-port oport
>
>
>
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> Gauche-devel mailing list
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> https://lists.sourceforge.net/lists/listinfo/gauche-devel
>

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<div dir=3D"ltr">Thanks.=C2=A0 Patch applied.<div><br></div><div><br></div>=
</div><br><div class=3D"gmail_quote"><div dir=3D"ltr" class=3D"gmail_attr">=
On Thu, Nov 7, 2024 at 9:17=E2=80=AFPM Jens Thiele &lt;<a href=3D"mailto:ka=
[email protected]">[email protected]</a>&gt; wrote:<br></div><blockquote class=3D"g=
mail_quote" style=3D"margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204=
,204,204);padding-left:1ex">Shiro Kawai &lt;<a href=3D"mailto:shiro.kawai@g=
mail.com" target=3D"_blank">[email protected]</a>&gt; writes:<br>
<br>
&gt; Oops, there was a reason we used `fold` in `print-object`.=C2=A0 =C2=
=A0A dictionary<br>
&gt; can be passed, which is traversable but not necessarily orderable, i.e=
.<br>
&gt; `for-each-with-index` can&#39;t be used.<br>
<br>
Ah sorry, missed that. Fixed it in the spirit of print-instance:<br>
<br>
diff --git a/lib/rfc/json.scm b/lib/rfc/json.scm<br>
index 73fd021ab..a8fdd7612 100644<br>
--- a/lib/rfc/json.scm<br>
+++ b/lib/rfc/json.scm<br>
@@ -245,44 +245,46 @@<br>
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=
=A0 &quot;can&#39;t convert Scheme object to json:&quot; obj)]))<br>
<br>
=C2=A0(define (print-object obj)<br>
-=C2=A0 (display &quot;{&quot;)<br>
-=C2=A0 (fold (^[attr comma]<br>
+=C2=A0 (write-char #\{)<br>
+=C2=A0 (fold (^[attr comma-needed?]<br>
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0(unless (pair? attr)<br>
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0(error &lt;json-construct-e=
rror&gt; :object obj<br>
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 &quot=
;construct-json needs an assoc list or dictionary, \<br>
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=
=A0but got:&quot; obj))<br>
-=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 (display comma)<br>
+=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 (when comma-needed?<br>
+=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 (write-char #\,))<br>
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0(print-string (x-&gt;string (car a=
ttr)))<br>
-=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 (display &quot;:&quot;)<br>
+=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 (write-char #\:)<br>
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0(print-value (cdr attr))<br>
-=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 &quot;,&quot;)<br>
-=C2=A0 =C2=A0 =C2=A0 =C2=A0 &quot;&quot; obj)<br>
-=C2=A0 (display &quot;}&quot;))<br>
+=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 #t)<br>
+=C2=A0 =C2=A0 =C2=A0 =C2=A0 #f obj)<br>
+=C2=A0 (write-char #\}))<br>
<br>
=C2=A0(define (print-array obj)<br>
-=C2=A0 (display &quot;[&quot;)<br>
+=C2=A0 (write-char #\[)<br>
=C2=A0 =C2=A0(for-each-with-index (^[i val]<br>
-=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=
=A0 =C2=A0 =C2=A0(unless (zero? i) (display &quot;,&quot;))<br>
+=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=
=A0 =C2=A0 =C2=A0(unless (zero? i) (write-char #\,))<br>
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=
=A0 =C2=A0 =C2=A0 (print-value val))<br>
-=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=
=A0 =C2=A0obj)<br>
-=C2=A0 (display &quot;]&quot;))<br>
+=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=
=A0 obj)<br>
+=C2=A0 (write-char #\]))<br>
<br>
=C2=A0(define (print-instance obj)=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0=
 ;&lt;json-mixin&gt;<br>
=C2=A0 =C2=A0(let1 class (class-of obj)<br>
-=C2=A0 =C2=A0 (display &quot;{&quot;)<br>
-=C2=A0 =C2=A0 (fold (^[slot comma]<br>
+=C2=A0 =C2=A0 (write-char #\{)<br>
+=C2=A0 =C2=A0 (fold (^[slot comma-needed?]<br>
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0(if-let1 json-name (slot-de=
finition-option slot :json-name #f)<br>
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0(begin<br>
-=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 (display comma)<br=
>
+=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 (when comma-needed=
?<br>
+=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 (write-char=
 #\,))<br>
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0(print-string=
 (if (eqv? json-name #t)<br>
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=
=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0(x-&gt;string (slot-definition=
-name slot))<br>
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=
=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0(x-&gt;string json-name)))<br>
-=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 (display &quot;:&q=
uot;)<br>
+=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 (write-char #\:)<b=
r>
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0(print-value =
(slot-ref obj (slot-definition-name slot)))<br>
-=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 &quot;,&quot;)<br>
-=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 comma))<br>
-=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 &quot;&quot; (class-slots class))<br>
-=C2=A0 =C2=A0 (display &quot;}&quot;)))<br>
+=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 #t)<br>
+=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 comma-needed?))<br>
+=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 #f (class-slots class))<br>
+=C2=A0 =C2=A0 (write-char #\})))<br>
<br>
=C2=A0(define (print-number num)<br>
=C2=A0 =C2=A0(cond [(or (not (real? num)) (not (finite? num)))<br>
@@ -307,9 +309,9 @@<br>
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 (if (&gt;=3D code #x10000)=
<br>
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 (for-each hexescape=
 (ucs4-&gt;utf16 code))<br>
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 (hexescape code)))]=
))<br>
-=C2=A0 (display &quot;\&quot;&quot;)<br>
+=C2=A0 (write-char #\&quot;)<br>
=C2=A0 =C2=A0(string-for-each print-char str)<br>
-=C2=A0 (display &quot;\&quot;&quot;))<br>
+=C2=A0 (write-char #\&quot;))<br>
<br>
=C2=A0(define (construct-json x :optional (oport (current-output-port)))<br=
>
=C2=A0 =C2=A0(with-output-to-port oport<br>
<br>
<br>
<br>
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Gauche-devel mailing list<br>
<a href=3D"mailto:[email protected]" target=3D"_blank">Gau=
[email protected]</a><br>
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=3D"noreferrer" target=3D"_blank">https://lists.sourceforge.net/lists/listi=
nfo/gauche-devel</a><br>
</blockquote></div>

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