Re: [Jscheme-devel] string->number

[Ken A. <kan...@bb...>]

OK, lets outsource the documentation.
Lets define string->number to be like the scheme documenatation, and have
string->literal for converting a string to a Java literal.

for the convenience of Java programmers, maybe we should define 
true, false, and null too.


k
At 10:44 AM 6/7/2004 -0400, Timothy John Hickey wrote:

>On Jun 7, 2004, at 10:24 AM, Ken Anderson wrote:
>
>>So the remaining issue is what should (string->number "08") return.  
>>It currently returns #f. i was hoping it would return 8.
>
>I can modify it so that string->number does not support the Java octal syntax by default.
>
>This little issue actually goes to the heart of JScheme since what is unique about Jscheme is the tight
>integration with Java and that integration is made possibly by our decision to adopt the Java primitive types
>as the Scheme base types. The Java literal syntax is then essential to making JScheme integrate smoothly with
>Java.
>
>Perhaps the idea should be that string->number has Scheme R4RS as its heritage and should therefore
>rely on the R4RS syntax primarily (hence disallowing octal notation entirely???)
>
>We could then follow Jonathan's suggestion and have a string->JavaNumber  procedure which would parse
>strings in the same way as the default Scheme reader parses numbers.
>
>This thread also raises the issue of documentation.
>
>One of my goals is to minimize documentation by outsourcing it, i.e. we can say that the JScheme literal syntax
>(at least in useJavaSyntax mode) is precisely the Java Literal syntax mode, except for some slight differences
>(#t  #f   #'...'     #(.....))
>This frees the Java programmer from having to learn a new syntax for literals and eases the transition between
>the two languages.
>
>---Tim----
>
>>
>>At 07:27 PM 6/6/2004 -0400, Timothy John Hickey wrote:
>>>I've modified string->number so that in the base 10 case it allows leading zeroes...
>>>The following Unit tests all pass in the current version of JScheme...
>>>
>>> "06/06/2004" ;; literal syntax, TJH
>>>
>>> ;; Default literal syntax is for Java literals,
>>>
>>> ;; but string->number will treat leading zeroes as decimal if base 10 is specified
>>>
>>> (equal? (.getClass '081) jsint.Symbol.class)
>>>
>>> (equal? (.getClass '0123Dig) jsint.Symbol.class)
>>>
>>> (equal? (.getClass '0123) java.lang.Integer.class)
>>>
>>> (equal? (string->number "081" 10) 81)
>>>
>>> (equal? (string->number "010") 10)
>>>
>>> (equal? (string->number "010" 8) 8)
>>>
>>> (equal? (tryCatch (string->number "081" 8) (lambda(e) 'error)) 'error)
>>>
>>> (equal? (string->number "08") #f)
>>>
>>> (equal? (string->number "08" 10) 8)
>>>
>>> (equal? (string->number "10") 8)
>>>
>>> (equal? (string->number "10" 10) 10)
>>>
>>>The implementation of string->number in the base 10 case is
>>>
>>>> public static Object schemeStringToNumber(String tok, int rdx) {
>>>>   try { return U.toNum(Long.parseLong(tok, rdx)); }
>>>>    catch (NumberFormatException e) {
>>>>        try {
>>>>            if (rdx!=10)
>>>>                return U.FALSE;
>>>>            else return new Double(tok); }
>>>>        catch (NumberFormatException e2)
>>>>            { return U.FALSE; }
>>>>    }
>>>> }
>>>
>>>---Tim---
>>>
>>>
>>>
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>>
>>
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