[cl-json-devel] Slot name with digits raise condition UNBOUND-SLOT

[Boris Smilga]

On 22 Jan 2013, at 11:28, Олег wrote:

>  (json:with-decoder-simple-clos-semantics
>   (let ((json:*json-symbols-package* nil))
>     (let ((x (json:decode-json-from-string
>                "{\"foo1\": [1, 2, 3], \"bar1\": true,
>                  \"baz1\": \"!\"}")))
>       (with-slots (foo1 bar1 baz1) x
>         (values x foo1 bar1 baz1)))))
>
>
> The slot FOO1 is unbound in the object #<#<JSON:FLUID-CLASS NIL
>                                            {1004085F33}>
>                                          {1003CAFB43}>.
>    [Condition of type UNBOUND-SLOT]
>


When Lisp slot names are derived from JSON object keys, they are  
transcribed to more Lisp-like conventions: camel case is replaced  
with hyphenation, all caps become framing asterisks, etc.  So, slot  
names in your Lisp code should be written with hyphens:

   (json:with-decoder-simple-clos-semantics
      (let ((json:*json-symbols-package* nil))
        (let ((x (json:decode-json-from-string
                   "{\"foo1\": [1, 2, 3], \"bar1\": true,
                     \"baz1\": \"!\"}")))
          (with-slots (foo-1 bar-1 baz-1) x
            (values x foo-1 bar-1 baz-1)))))



   => #<#<JSON:FLUID-CLASS NIL {5D03A341}> {5A1ECF11}>

   => #(1 2 3)

   => T
   =>"!"

If this disagrees too much with the conventions of your code, you can  
change the way identifiers are transcribed by setting / rebinding the  
variable *JSON-IDENTIFIER-NAME-TO-LISP* to the appropriate  
transcriber function.

Hope this helps.

  — B. Smilga.

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