Re: question about string expression evaluation / bug?

Reply to message «Re: question about string expression evaluation / bug?»,
sent 22:07:10 23 May 2011, Monday
by hsitz:

> :set ignorecase
> :echo 'abc' is 'ABC' (output is 1)
Missed this. Strange, but `is#' works (guess it is because `#' and `?' are
defined as operator suffix for all expr4 operators). I guess it should be added
to the help (undocumented=non-existent) as I don't want to dig into my own code
and guess where I should write `type(v1)==type(v2) && v1==#v2' and where just
`v1==#v2', replacing all is's with is# is simpler.

> Still wondering about the issue with different values for my empty
> string comparison, though. Seems like it must be a bug in either
> design or implementation of 'ignorecase'. I wonder whether with
> 'ignorecase' set the expression: 'abc' > '' returns 0 on 64-bit vim
> and 1 on 32-bit. . .
I have 64-bit one. I once thought that problem is strcasecmp in my glibc, but
quickly searching vim source revealed that it uses its own mb_strnicmp.

Original message:
> On May 23, 8:12 am, hsitz <hes...@gmail.com> wrote:
> > > This is a reason why I never use `==', `!=', `>', `>=', `<', `<=' for
> > > comparing strings, only `is'/`isnot' (it looks better then `==#' and
> > > `!=#') and operators with either `?' or `#' at the end.
>
> Zyx -- I didn't even realize 'is'/'isnot' were defined for strings.
> However, it seems that they are equivalent to '==' and '!=' and not
> the matchcase operators you suggest. From the docs:
> "the original |List|. When using "is" without a |List| it is
> equivalent to
> using "equal", using "isnot" equivalent to using "not equal". Except
> that a
> different type means the values are different. "4 == '4'" is true, "4
> is '4'"
> is false."
>
> E.g.,
>
> :set ignorecase
> :echo 'abc' is 'ABC' (output is 1)
> :echo 'abc' == 'ABC' (output is 1)
> :echo 'abc' ==# 'ABC' (output is 0)
>
> Your point about specifying matchcase or ignorecase expressly is a
> good one. I will be modifying my code to do that.
>
> Still wondering about the issue with different values for my empty
> string comparison, though. Seems like it must be a bug in either
> design or implementation of 'ignorecase'. I wonder whether with
> 'ignorecase' set the expression: 'abc' > '' returns 0 on 64-bit vim
> and 1 on 32-bit. . .
>
> -- Herb
>
> > Zyx -- Thanks very much, I think you're onto something.
> >
> > However on my machine the two expressions you give above both evaluate
> > to 1. What is the explanation for the difference?:
> > ------------------------------------------
> > :echo 'DONE' ># ''
> > 1
> >
> > :echo 'DONE' >? ''
> >
> > 1
> > ----------------------------------------