idlwave-pad-keyword

idlwave-pad-keyword is a variable defined in `idlwave.el'.
Its value is

t

Documentation:
Non-nil means pad '=' in keywords (routine calls or defs) like assignment.
Whenever `idlwave-surround' is non-nil then this affects how '=' is
padded for keywords and for variables. If t, pad the same as for
assignments. If nil then spaces are removed. With any other value,
spaces are left unchanged.

You can customize this variable.