Re: API design question for dbf.py

2012-07-06 Thread MRAB 

On 06/07/2012 22:34, Ethan Furman wrote:

I'm looking for some free advice.  ;)

My dbf module has three basic containers, all of which support list-like
access:  Table, List, and Index, each of which is filled with _DbfRecords.

The fun part is that a _DbfRecord can compare equal to another
_DbfRecord, a _DbfRecordTemplate, a tuple with the same values in the
same locations, or a dict with the same keys/fields and values.

The really fun part is __contains__:  should the __contains__ method
return True when a _DbfRecordTemplate, tuple, or dict is looked up in
the Table, List, or Index and there is a matching record?


Well, if x is in c and x == y, then y is in c. Does that help? ;-)
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Re: API design question for dbf.py

2012-07-06 Thread Ethan Furman 

MRAB wrote:

On 06/07/2012 22:34, Ethan Furman wrote:

I'm looking for some free advice.  ;)

My dbf module has three basic containers, all of which support list-like
access:  Table, List, and Index, each of which is filled with 
_DbfRecords.


The fun part is that a _DbfRecord can compare equal to another
_DbfRecord, a _DbfRecordTemplate, a tuple with the same values in the
same locations, or a dict with the same keys/fields and values.

The really fun part is __contains__:  should the __contains__ method
return True when a _DbfRecordTemplate, tuple, or dict is looked up in
the Table, List, or Index and there is a matching record?


Well, if x is in c and x == y, then y is in c. Does that help? ;-)


Heh, that's pretty much the conclusion I was coming to.  As a more 
concrete example:


-- x = 4.0
-- x in [1, 4, 7, 4, 9, 3, 4]
True

It's checking for equality, not identity.

Thinks for helping me think that through.

~Ethan~
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Re: API design question for dbf.py

2012-07-06 Thread Devin Jeanpierre 
On Fri, Jul 6, 2012 at 6:46 PM, Ethan Furman et...@stoneleaf.us wrote:
 It's checking for equality, not identity.

   x = float('nan')
   x in [x]
  True

It's checking for equality OR identity.

-- Devin
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Re: API design question for dbf.py

2012-07-06 Thread Ethan Furman 

Devin Jeanpierre wrote:

On Fri, Jul 6, 2012 at 6:46 PM, Ethan Furman et...@stoneleaf.us wrote:

It's checking for equality, not identity.


   x = float('nan')
   x in [x]
  True

It's checking for equality OR identity.


Good point.  In my case, checking for equality will cover both cases.

~Ethan~
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