'range' should support an integer operand.

[gopherbot]

by jesse.dailey:

The 'range' clause should support an integer as it's right operand.

Such as:

for i := range 10 {
  // do stuff ten times, i = 0,1,...9
}

Or similar.  Analogous to the way the range() iterator works in python.

[rsc]

Comment 1:

Labels changed: added language-change.

Status changed to Thinking.

[gopherbot]

Comment 2 by consalus:

I don't think it makes sense to iterate over an integer, as an integer isn't a range.
Why not just 
func Between(a, b int) chan int {
   c := make(chan int);
   go func() {
     for a < b {
       c<- a;
       a += 1;
     }
   }();
   return c;
}
for i := range Between(0, 10) {
}
?
One could even do fancy things with having Between() return iterfaces such that you
could also do Between(0, 1000).By(2) or From(1000).DownTo(20).
Much more flexible than building it into the language, and conceptually nicer too, imho.

[gopherbot]

Comment 3 by jesse.dailey:

That is a nice little generator pattern there, and I like it a lot conceptually.
But, I think it's the wrong fit for this particular corner of the language.
I'd be happy enough I suppose if there were just an import that had something like 
you describe.  But, let me make my case for why it makes sense in terms of language 
design and performance.
The RangeClause is added to the language for the purpose of substituting for the 
ForClause.  All the other iterations that range does are things one could do with a 
longer form ForClause, but RangeClause exists to make 'for' more expressive, with 
less cruft.  What is the most common ForClause in the world?
for i := 0; i < N; i++ { }
In order to express this you really need to be able to provide: start, end, and 
stride to produce a range of integers.
Also, a for-loop is an extremely tight piece of machine code, so you'd be replacing a 
few cmps and adds with launching a new goroutine and doing channel I/O... and all 
that I/O would compound-scale as you chain new steps on (so when you add .By(2) you 
don't cut your workload in half, you double it)... where adding a stride of 2 to 
range simply gets you the half of the results you wanted with no additional overhead.

[gopherbot]

Comment 4 by hall.jeff:

I think the original request was basically to default start = 0 and stride = 1... no
real "magic" there

[robpike]

Comment 5:

Status changed to WontFix.