percent (%) special character

## Description

Some predefined variables names begin with `%`, such as `%i` (for `sqrt(-1)`), `%inf` (for `Infinity`), `%pi` (for `3.14...`), `%T` (for the boolean constant `"true"`),...

In addition, functions whose names begin with `%` are special : they are used for primitives and operators overloading (see `overloading`).

For example the function `%rmr` performs the multiplication (`m`) operation `x*y` for `x` and `y` rational matrices (`r`). The coding conventions are given in the overloading help page.

## Examples

    x1=tlist('x',1,2);
    x2=tlist('x',2,3);
    deff('x=%xmx(x1,x2)','x=list(''x'',x1(2)*x2(2),x2(3)*x2(3))');
    x1*x2

## See also

- overloading