Re: checking for nil argument in interactive

[Seb <spluque@gmail.com>]

On Sun, 09 Nov 2008 22:20:18 +0100,
Tassilo Horn <tassilo@member.fsf.org> wrote:

> See the manual for details.  ,----[ (info "(elisp)Equality
> Predicates") ]
>> -- Function: eq object1 object2 This function returns `t' if OBJECT1
>> and OBJECT2 are the same object, `nil' otherwise.
>> 
>> `eq' returns `t' if OBJECT1 and OBJECT2 are integers with the same
>> value.  Also, since symbol names are normally unique, if the
>> arguments are symbols with the same name, they are `eq'.  For other
>> types (e.g., lists, vectors, strings), two arguments with the same
>> contents or elements are not necessarily `eq' to each other: they are
>> `eq' only if they are the same object, meaning that a change in the
>> contents of one will be reflected by the same change in the contents
>> of the other.
>> 
>> (eq 'foo 'foo) => t
>> 
>> (eq 456 456) => t
>> 
>> (eq "asdf" "asdf") => nil
> `----

> So to compare stings use `string='.

Thanks Tassilo!


-- 
Seb