Re: 'true'::TEXT::BOOLEAN

Bruno Wolff III <bruno@wolff.to> writes:
>   Markus Bertheau ??? <twanger@bluetwanger.de> wrote:
>> I think casting from text to boolean should be possible, and use the
>> same algorithm that's used when casting from "unknown" to boolean.

> You probably want boolin.

That won't actually work either, because boolin wants cstring:

egression=# select boolin('f'::text);
ERROR:  function boolin(text) does not exist
HINT:  No function matches the given name and argument types. You may need to add explicit type casts.

You can get it to work like this, if you're determined:

regression=# select boolin(textout('f'::text));boolin
--------f
(1 row)

and of course

regression=# select textin(boolout(true));textin
--------t
(1 row)

There's been discussion of allowing all datatypes to be explicitly
casted to or from text by generating conversions like these
automatically.  But I'm not sure if everyone's convinced it's a good
idea or not.  You'd also have to argue about whether varchar should
be included in the special dispensation ...
        regards, tom lane