'returns' vs 'of'

I don't like the assignments of 'returns' and 'of'.  I think it is easily confused.  I've written

foo (Int $x)
returns Int

in examples and nobody noticed.  As formal documentation, that scans right as the outer perceived return value type.  But no, it's supposed to be

foo (Int $x)
of Int

instead.  The returns keyword affects the implementation of the function, not the external contract.  

Yet, if returns is missing it uses the of value by default, but if the of is missing it does not give static type checking to the caller, rather than using the same as the returns.

Will other programmers make the same mistake?  I think it's going to be a problem.  It's like thinking you used strict but did not, and the compiler wasn't telling you things it should have.

--John
0
dhcgnd702
4/13/2008 5:28:00 AM
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On Apr 13, 2008, at 1:28 , John M. Dlugosz wrote:
> I don't like the assignments of 'returns' and 'of'.  I think it is  
> easily confused.  I've written
>
> foo (Int $x)
> returns Int

I think the main problem here is that "of" is there only for  
completeness; one would normally say

our Int sub foo (Int $x)

that is, "of" only exists to let you put the type afterward with  
other traits.  Thus "returns" should stand out as something unusual.   
If the Synopsis leads you to think "of" is the correct way to declare  
an outer/contract type, it should probably be clarified.

Beyond that, yes it's somewhat confusing.  But I'm not sure there's a  
way to specify the difference that (a) meets the Huffman-coding  
design constraint and (b) isn't *really* klunky ("of" is rather  
klunky as is, tbh).  @Larry?  (And yes, I'm aware it's been discussed  
before, see archive link in previous msg :)

-- 
brandon s. allbery [solaris,freebsd,perl,pugs,haskell] allbery@kf8nh.com
system administrator [openafs,heimdal,too many hats] allbery@ece.cmu.edu
electrical and computer engineering, carnegie mellon university    KF8NH


0
allbery
4/13/2008 2:02:33 PM
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