* Reflection on function argument types
@ 2016-12-28 5:38 Duncan Mak
2017-01-01 18:19 ` Per Bothner
0 siblings, 1 reply; 2+ messages in thread
From: Duncan Mak @ 2016-12-28 5:38 UTC (permalink / raw)
To: kawa mailing list
Hello all,
Happy holidays!
I'm playing around with Kawa over Christmas break to learn more how
functions are represented in the system.
I wrote the following code:
(import (srfi 1))
(define (foo (a :: integer)) (+ a a))
(define (hello-number (n :: number) (i :: number)) (list "number" n))
(define (hello-string (s :: string)) (list "string" s))
(define (print-types (func :: gnu.mapping.MethodProc))
(display (procedure-property func 'name)) (newline)
(for-each (lambda (t) (display t) (newline))
(map (lambda (i) (func:getParameterType i)) (iota
(func:numParameters))))
(newline))
(print-types foo)
(print-types hello-number)
(print-types hello-string)
I'm surprise to see that the output differs between foo and hello-*:
foo
Type integer
hello-number
ClassType java.lang.Object
ClassType java.lang.Object
hello-string
ClassType java.lang.Object
Why is it that I only see java.lang.Object for the hello-* functions?
Shouldn't number and string show up, like it did for foo?
Thanks!
--
Duncan.
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: Reflection on function argument types
2016-12-28 5:38 Reflection on function argument types Duncan Mak
@ 2017-01-01 18:19 ` Per Bothner
0 siblings, 0 replies; 2+ messages in thread
From: Per Bothner @ 2017-01-01 18:19 UTC (permalink / raw)
To: Duncan Mak, kawa mailing list
On 12/27/2016 09:34 PM, Duncan Mak wrote:
> I wrote the following code:
>
> (import (srfi 1))
> (define (foo (a :: integer)) (+ a a))
> (define (hello-number (n :: number) (i :: number)) (list "number" n))
> (define (hello-string (s :: string)) (list "string" s))
> (define (print-types (func :: gnu.mapping.MethodProc))
> (display (procedure-property func 'name)) (newline)
> (for-each (lambda (t) (display t) (newline))
> (map (lambda (i) (func:getParameterType i)) (iota
> (func:numParameters))))
> (newline))
> (print-types foo)
> (print-types hello-number)
> (print-types hello-string)
>
> I'm surprise to see that the output differs between foo and hello-*:
>
> foo
> Type integer
>
> hello-number
> ClassType java.lang.Object
> ClassType java.lang.Object
>
> hello-string
> ClassType java.lang.Object
>
> Why is it that I only see java.lang.Object for the hello-* functions?
> Shouldn't number and string show up, like it did for foo?
This turns out to be a problem with demangling. 'foo' works because
it doesn't have any special characters.
In ModuleMethod.java in resolveParameterTypes it says:
String mangledName = Mangling.mangleNameIfNeeded(name);
but it should be:
String mangledName = Mangling.mangleName(name);
Unfortunately, fixing this improves the accuracy of type-checking
enough to cause some problems. For example this code
(simplified from r7rs-tests.scm):
(let ((val 'abc))
(cond ((and (complex? val)
(not (nan? val)))
(display val))))
Kawa complains that the call to nan? is invalid because the argument val
is a symbol. This is bogus, since the previous test to complex? ensures
nan? is never called.
I created this issue:
https://gitlab.com/kashell/Kawa/issues/1
--
--Per Bothner
per@bothner.com http://per.bothner.com/
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