OpenEuphoria

Re: Eu improvements (Part 1)

• Posted by James W Hofmann <jhofmann at ucsc.edu> Jan 04, 2007
• 516 views

Jason Gade wrote:
> 
> This looks interesting, but I would like to see a more substantive example.
> 
> What would be the effect of without typecheck?

Original source

type Point(sequence s)
    index x=s[1]
    index y=s[2]
    return length(s)=2
end type

Point p
sequence q
p={0,0} -- initialize
q={5,5}

for nx=1 to 10 do
    p.x = nx
    ? p.x
    p.y = p.x+1
    ? p.y
end for

-- output is 1,2,2,3,3,4,4,5,5,6,6,7,7...

? q:Point.x -- output is 5

Typecheck off makes it into this equivalent:

sequence p
sequence q
p={0,0} -- initialize
q={5,5}

for nx=1 to 10 do
    p[1] = nx
    ? p[1]
    p[2] = p[2]+1
    ? p[2]
end for

? q[1] -- output is 5

At least, I think that's how it would look. A simple replacement of
name-notation with number-notation.

> I kind of like the first example better but then use the colon notation as
> kind
> of a "cast". Maybe. Hmm.

Both notations could work, because they do different things.
Dot-only(simple-dot?) notation says "use the type that you declared the
variable as."
Colon-dot notation says "try to use this particular type on this variable."

In the above example I used simple-dot because it felt natural to me after
doing it so often to reference class variables in Python. But having the
other seems like a reasonable idea for code needing greater structure. I
don't really have a good feel for the potential downsides, though.