5.1 Information about a function

returns the name of a function. For operations, this is the name used in their declaration. For functions, this is the variable name they were first assigned to. (For some internal functions, this might be a name different from the name that is documented.) If no such name exists, "unknown" is returned.

gap> NameFunction(SylowSubgroup);
"SylowSubgroup"
gap> Blubberflutsch:=x->x;;
gap> NameFunction(Blubberflutsch);
"Blubberflutsch"
gap> a:=Blubberflutsch;;
gap> NameFunction(a);             
"Blubberflutsch"
gap> NameFunction(x->x);
"unknown"
gap> NameFunction(NameFunction);
"NAME_FUNC"

returns the number of arguments the function func accepts. For functions that use arg to take a variable number of arguments, as well as for operations, -1 is returned. For attributes, 1 is returned.

gap> NumberArgumentsFunction(function(a,b,c,d,e,f,g,h,i,j,k)return 1;end); 
11
gap> NumberArgumentsFunction(Size);                   
1
gap> NumberArgumentsFunction(IsCollsCollsElms);
3
gap> NumberArgumentsFunction(Sum);               
-1

[Top] [Up] [Next] [Index]