From: "Michael W. Ryder" <_mwryder@...>
Date: 2007-05-25T09:45:05+09:00
Subject: Re: Introducing the "it" keyword

Greg Fodor wrote:
>> This break in concentration can be a real killer in finding obscure bugs.
>> My proposal also suffers from some of this problem but as it is
>> "inherited" from regular expressions it may be easier to figure out.
>>
> I understand these concerns. The pipes are just sugar, it seems like
> it
> would be a small learning curve to me, but here are a few other ideas:
> 
> puts it if (x + y) * (it = (a - b)) < 10
> puts it if (x + y) * ((a - b) as_it) < 10
> puts it if (x + y) * (<it>(a - b)) < 10
> 
> It's not quite convincing that having an explicit relationship between
> it => pipes, once learned, is more difficult to read/parse in your
> head than scanning parentheses to figure out which are being used
> as storage and which are not. (And if you said $8, which one is
> actually
> $8 and not $7! :))
> 
> When I first learned Ruby, reading:
> 
> return x if x < 5
> 
> Was really counterintuitive at first cause my brain was used to
> thinking
> "if I see 'return', it's going to return if I got to that line  in the
> code." I had to unlearn that assumption, and read the full line
> checking
> for the trailing condition.
> 

As I have been programming in Business Basic for over 25 years I am used 
to seeing statements like: IF A$="" RETURN so I didn't have any problems 
with conditional returns.

> I see that mental leap as being many times more difficult to learn
> than
> associating an expression wrapped in pipes (or other sugar) with the
> 'it'
> keyword.
> 
> Although, I'll grant that if there is a solution that functionally
> meets
> my list that uses idioms from another domain like regular expressions
> it
> might be a good contender. Maybe you can explain more about the flags
> thing with an example to see how it feels vs. the pipes approach?
> 

If you had a statement like : puts $1 if (?:x + y) + (z * 2) < 10, then 
the program would print z * 2 if the expression evaluated to less than 
10.  The ?: flag tells the parser to not store the value of x + y.