Re: install name collision

[Bill Allombert <Bill.Allombert@math.u-bordeaux1.fr>]

On Tue, Jul 24, 2012 at 10:58:14PM -0400, Charles Greathouse wrote:
> I wrote a .gp.c file which includes, among other things, a function
> called vecsum. It was based on a gp2c conversion, and includes
> 
> GP;install("vecsum","G","vecsum","./auto.gp.so");
> 
> in a comment so that gp2c-run will load it. (Yes, this is a silly
> function, but I mention it up only for the bug report.)
> 
> Usually this procedure works fine, and indeed it seems to here:
> 
> 
>   ***   at top-level: rec([23124110,141322
>   ***                 ^--------------------
>   ***   in function findrecd: ...max(c)==1&&vecmin(c)==0&&vecsum(c)==1)||c==[1
>   ***                                                     ^--------------------
>   ***   variable name expected.
>   ***   Break loop: type 'break' to go back to GP

You must make sure all install() and alias() commands are executed before any
GP functions using the new symbols are defined. Otherwise the GP compiler use
the old value of the symbol instead of the new one.

? f(a)=addii(a,123);
? install(addii,GG)
? f(5)
  ***   at top-level: f(5)
  ***                 ^----
  ***   in function f: addii(a,123)
  ***                  ^------------
  ***   variable name expected.

...

? install(addii,GG)
? f(a)=addii(a,123);
? f(5)
%2 = 128

(by contrast, GP function are dynamic: you can define them after they are used
in other functions, but this incurs some penalties).

Cheers,
Bill.