Anthony Borla writes:
> Greetings,
>
> Ouput from the following code:
>
> {System.showInfo ~1} %% (1)
> {System.showInfo ~1.0} %% (2)
>
> {System.showInfo {VirtualString.changeSign {IntToString ~1} &-}}
> {System.showInfo {VirtualString.changeSign {IntToString ~1} "-"}}
>
> is:
>
> -1
> -1.0
> ~1
> ~1
>
> Obviously some sort of implicit conversion is being performed at (1) and
> (2).
I am a bit confused about your question. ~1 is the lexical string
that reprsents -1. So the lexer/parser turns the string ~1 into an
internal value of -1. ShowInfo prints -1 as the string "-1"
This behaviour is sort of hinted at in the documentation of
VirtualString.toString:
" The transformation is straightforward: Atoms (except nil and '#'),
integers, floats and byte strings are transformed into strings using
Atom.toString, Int.toString, Float.toString, and ByteString.toString
respectively, where in numbers - is used instead of ~."
IntToString converts the value -1 into the string "~1" (as per
documentation it converts to a string in Oz Concrete syntax)
> My question is: what routine(s) need to be called in order to
> explicitly perform this task ?
>
What task do you want to perform?
> I would have thought it was 'VirtualString.changeSign', but all my attempts
> to so use it are failing.
>
See the difference in:
{System.showInfo ~3.14}
{System.showInfo {VirtualString.changeSign ~3.14 '~'}}
Hope this helps
k
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