allowing value evaluations as statements

[askok@...]

A perl-ish way of making error checking, but neat and 
effective:

_= nsfm:fileExistsAtPath(testfile)
    or error "File doesn't exist!"

_= nsfm:copyPath( testfile, newfile )
    or error "File copy failed!"

Currently, Lua does not allow leaving the "_=" away, since 
that would make these commands and commands don't have a 
value ('or' gives this a value).

In my opinion, evaluation results could be allowed even if 
the value is not stored anyway.  In a way, they would have 
a "drain" that eats up the value.

I do know that by a function this can be overcome, but the 
neaty is to have the essential thing first (the command), 
and ability to switch on/off the error check by simply 
commenting that out.  Anyways, this is caused by my 
exposure to perl lately, it does show. Perl has a lot of 
those thisandthat or die things..  Which I actually 
like(d).

-asko