[Grace-core] Fwd: Query on built-in objects

[Kim Bruce]

I think we want to allow students to write
   print (7)
rather than have to write
  print "{7}"
or
  print (7.asString)

This leads me to believe it should take an argument with type {asString -> String}, where asString on Strings is just the identity function.  However, I'd be happy to hear arguments to the contrary.

Kim



On Jun 18, 2012, at 11:31 PM, James Noble wrote:

>> So Smita's question is: why do Numbers have a ++ method (which converts to string and then concatenates), while Booleans don't have one.
> 
> good question. We haven't started systematically on library design
> (a good reason to get modules & annotations (& generics) done...)
> 
>> Clearly we should be consistent, but I'm wondering which is best.  I think that it's quite reasonable to use ++ to mean concatenation of any sequence, such as a list of numbers ... so automatic conversion to string seems wrong.
> 
> yes, makes sense to me.
> Probably not using plain "+" for concatenation is best, although I saw a study somewhere 
> 
> (http://www.springerlink.com/content/1537m70w13591624/, pg91)
> 
> saying that "fire" + "fox" was quite understandable as yeilding "firefox" 
> (for various reasons, this is about the only result from that study I really trust)
> 
> J
> 
>> 	Andrew
>> 
>> Begin forwarded message:
>> 
>>> Professor Black,
>>> 
>>> I found an interesting behavior in Grace, while working on Strings, Numbers and Boolean built-in objects.
>>> 
>>> Concatenation of Number and String works fine with ++ operator, but throws an error when I tried the same with Boolean and Number, and Boolean and String.
>>> 
>>> Example: 1 - Boolean and Number/String
>>> 
>>> var a:= true
>>> var b:= " smita"
>>> print (a ++ b)
>>> 
>>> Error around line 3: Method lookup error: no ++ in Boolean.
>>> Called Boolean.++ (3)
>> 
>> _______________________________________________
>> Grace-core mailing list
>> Grace-core at cecs.pdx.edu
>> https://mailhost.cecs.pdx.edu/mailman/listinfo/grace-core
> 
> _______________________________________________
> Grace-core mailing list
> Grace-core at cecs.pdx.edu
> https://mailhost.cecs.pdx.edu/mailman/listinfo/grace-core