MaplePrimes - answers and comments on Question, Write procedures which return procedures itself?

Would someone please correct

848380 — Sun, 07 Mar 2010 16:44:06 Z

Would someone please correct my grammar error (s/itself/themselve) and delete this post?

example

Joe Riel — Sun, 07 Mar 2010 21:36:43 Z

(**) f := k -> x -> k*x:
(**) g := f(3):
(**) g(a); 
                                                  3 a

The proc form is more general.  It permits multiple statements and optional arguments.

First of all, thank you, and

848380 — Mon, 08 Mar 2010 02:38:42 Z

First of all, thank you, and second:
Why doesn't
f := x -> if x <= 0 then 0 else 1 end if;
work?

Edit: I just found out that
if(x <= 0, 0, 1);
works, but it's not the same and I fear that this expression could diverge in some cases, in case all subexpressions of it are evaluated no matter what case applies. In the above situation only the corresponding subexpression would be evaluated I guess, not all at once so the danger of a diverging expression would be smaller.

Well it tells me "Error,

848380 — Mon, 08 Mar 2010 02:52:57 Z

Well it tells me
"Error, invalid arrow procedure"
and I'm typing exactly the same as you did?

Edit: I just found out the reason why: When changing to Maple input from 2D Output, it suddenly works, but why?

Why do you say it doesn't

Joe Riel — Mon, 08 Mar 2010 02:44:37 Z

Why do you say it doesn't work? Using command-line maple I get

(**) f := x -> if x <= 0 then 0 else 1 end if;
(**) f(2);                         
                                   1
(**) f(0);                         
                                   0
(**) f(-1);
                                   0

parser difference

acer — Mon, 08 Mar 2010 03:11:06 Z

This is the first parser difference I mention here.

acer