reading file : bad syntax (multiple expressions after identifier)
Pergunta
(define bootstrap-c-code
(define (from-file file-name)
(let* ((ip (open-input-file file-name))
(res (read-text-file-from-input-port ip)))
(close-input-port ip)
res))
(from-file "llvm.c"))
Error : define: bad syntax (multiple expressions after identifier)
But I can't see anything wrong with it. Can someone explain / fix it please.
Solução
It's not clear what you intended with the above code. If you were trying to load a text file and leave the loaded value in a variable called bootstrap-c-code
, then try this:
(define bootstrap-c-code
(let ((from-file
(lambda (file-name)
(let* ((ip (open-input-file file-name))
(res (read-text-file-from-input-port ip)))
(close-input-port ip)
res))))
(from-file "llvm.c")))
Of course, the from-file
definition will only be visible inside the let
, if you need to use it outside, define
it outside of the whole expression. If you only need the functionality of from-file
inside the let
, you can obtain the same result in a much simpler way:
(define bootstrap-c-code
(let* ((ip (open-input-file "llvm.c"))
(res (read-text-file-from-input-port ip)))
(close-input-port ip)
res))
On the other hand, if what you intended was to create a procedure called bootstrap-c-code
, then the correct syntax would be:
(define (bootstrap-c-code)
(define (from-file file-name)
(let* ((ip (open-input-file file-name))
(res (read-text-file-from-input-port ip)))
(close-input-port ip)
res))
(from-file "llvm.c"))
Outras dicas
According to R5RS, internal definitions can occur only at the beginning of the of a bunch of forms like let, let*, lambda etc. In the case of your code, that is not the case since you have an internal definition inside a non-procedural define. You could fix it by making `bootstrap-c-code' bind to a procedure.