Re[2]: UDF library was: Re[2]: [Firebird-devel] Firebird 1.5

[Nickolay S. <sk...@bs...>]

Hello, Helen !

> At 12:50 AM 31/07/2003 +0400, Nickolay Samofatov wrote:
>>Hello, Paul !
>>
>>I prepared a patch to change ltrim and rtrim behaviour
>>to return NULL for any number of spaces including zero.

> Why?  What is the justification for breaking the established behaviour?

I'm not breaking the behaviour. I just fix errors.

currently,

rtrim(NULL) = NULL
rtrim('') = NULL
rtrim(' ') = ' '
rtrim('  ') = ' '
rtrim('   ') = ' '

ltrim(NULL) = NULL
ltrim('') = NULL
ltrim(' ') = '' (Note: ltrim(ltrim(' ')) != ltrim(' '))


> If I pass a string, I want to get a trimmed string back, just as in Delphi, 
> which the UDF mimics and which years of application code relies on.

You'll get it. My change affects only trimming string consisted only of
spaces.

> If change were in sight (as I don't believe it was at this time, only a 
> bug-fix to the existing UDF) a correct approach would be to bring TRIM into 
> line with the standard.  Use the verb TRIM with keyword LEADING | TRAILING 
> | BOTH and allow for the trimming of ANY specified character (with space as 
> the default).

> e.g.
> TRIM (LEADING ' ' FROM '    TEST    ') yields 'TEST    '
> TRIM (TRAILING ' ' FROM '    TEST    ') yields '    TEST'
> TRIM (BOTH ' ' FROM '    TEST    ') yields 'TEST'
> TRIM (BOTH 'T' FROM 'TEST') yields 'ES'

This would be nice and is not too hard to implement. Volunteers ?

> Helen

Nickolay Samofatov