Misplaced syntactic keyword defvar

Misplaced syntactic keyword defvar

[Bill Schottstaedt]

In the current CVS Guile:


/home/bil/cl/ ../test/bin/guile
guile> (define defvar #f)
guile> (set! defvar define)
guile> (set! defvar define)

Backtrace:
In standard input:
    3: 0* (set! defvar define)

standard input:3:1: In procedure memoization in expression (set! defvar define):
standard input:3:1: Misplaced syntactic keyword defvar.
ABORT: (syntax-error)
guile>


Even shorter, though I'm not sure this is legal:

guile> (set! define define)

Backtrace:
In standard input:
    1: 0* (set! define define)

standard input:1:1: In procedure memoization in expression (set! define define):
standard input:1:1: Misplaced syntactic keyword define.
ABORT: (syntax-error)


(The first example is abstracted from a larger context where I'm using
the same code in both Scheme and Common Lisp).



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Re: Misplaced syntactic keyword defvar

[Dirk Herrmann]

Bill Schottstaedt wrote:

>  In the current CVS Guile:
>
>  /home/bil/cl/ ../test/bin/guile guile> (define defvar #f) guile>
>  (set! defvar define) guile> (set! defvar define)
>
>  Backtrace: In standard input: 3: 0* (set! defvar define)
>
>  standard input:3:1: In procedure memoization in expression (set!
>  defvar define): standard input:3:1: Misplaced syntactic keyword
>  defvar. ABORT: (syntax-error) guile>

Fixed. The problem had been introduced by me.

Best regards
Dirk



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Re: Misplaced syntactic keyword defvar

[Bill Schottstaedt]

Now (in Saturday's CVS Guile) I get this:

guile> (define defvar #f)
guile> (set! defvar define)
guile> (set! defvar define)

Backtrace:
In standard input:
    4: 0* (set! #<primitive-builtin-macro! define> define)

standard input:4:1: In expression (set! #<primitive-builtin-macro! define> define):
standard input:4:1: Unbound variable: #<primitive-builtin-macro! define>
ABORT: (unbound-variable)



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Re: Misplaced syntactic keyword defvar

[Dirk Herrmann]

Bill Schottstaedt wrote:

> Now (in Saturday's CVS Guile) I get this:
>
> guile> (define defvar #f)
> guile> (set! defvar define)
> guile> (set! defvar define)
>
> Backtrace:
> In standard input:
>    4: 0* (set! #<primitive-builtin-macro! define> define)
>
> standard input:4:1: In expression (set! #<primitive-builtin-macro! 
> define> define):
> standard input:4:1: Unbound variable: #<primitive-builtin-macro! define>
> ABORT: (unbound-variable)

I have submitted a hopefully working fix this time. But, just as a reminder:

  (define defvar #f)
  (set! defvar define)

is not allowed according to R5RS. Neither is

  (set! define #f)

In R5RS you don't find the concept that define and other syntactic keywords
have a location to which you can assign. The same holds for the concept that
for every syntactic keyword there is a corresponding macro object. Both of
these are guile extensions, but their use should probably be avoided.

Best regards
Dirk



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