* make-hash-table: Wrong type argument
@ 2008-07-09 8:34 Shakthi Kannan
2008-07-10 7:35 ` Ludovic Courtès
0 siblings, 1 reply; 2+ messages in thread
From: Shakthi Kannan @ 2008-07-09 8:34 UTC (permalink / raw
To: guile-user
Hi,
Newbie here. I am trying to pass key/value to a procedure to add it to
the hash-table. It fails at:
"you"ERROR: In procedure hash_fn_create_handle_x:
ERROR: Wrong type argument in position 1: "foo"
=== BEGIN ===
#!/usr/local/bin/guile -s
-e main -s
!#
(use-modules (ice-9 rdelim))
(define make-dictionary
(lambda (name size)
(lambda ()
(define name (make-hash-table size)))))
(define add-to-dictionary
(lambda (table key value)
(write value)
(hash-set! table key value)))
(define (main args)
(make-dictionary "foo" 4)
(add-to-dictionary "foo" 'u "you")
)
=== END ===
What am I missing? Is this abstraction ok?
Thanks!
SK
--
Shakthi Kannan
http://www.shakthimaan.com
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: make-hash-table: Wrong type argument
2008-07-09 8:34 make-hash-table: Wrong type argument Shakthi Kannan
@ 2008-07-10 7:35 ` Ludovic Courtès
0 siblings, 0 replies; 2+ messages in thread
From: Ludovic Courtès @ 2008-07-10 7:35 UTC (permalink / raw
To: guile-user
Hi,
"Shakthi Kannan" <shakthimaan@gmail.com> writes:
> Newbie here. I am trying to pass key/value to a procedure to add it to
> the hash-table. It fails at:
>
> "you"ERROR: In procedure hash_fn_create_handle_x:
> ERROR: Wrong type argument in position 1: "foo"
Note: If you run Guile with `--debug', you should get a nice backtrace
here.
The problem is that you pass `hash-set!' the string "foo" as its first
argument, while it expects a hash table (as returned by
`make-hash-table').
I think there is some confusion:
> (define make-dictionary
> (lambda (name size)
> (lambda ()
> (define name (make-hash-table size)))))
`define' here is an "internal define", i.e., it defines a variable
that's local to the lambda where it occurs. Furthermore, `name' is
taken literally, it's not substituted by the actual parameter passed to
`make-dictionary'.
Hope this helps,
Ludovic.
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