[Bioperl-l] evalues/floating point tests

Mark A. Jensen maj at fortinbras.us
Sun Jan 18 19:22:26 EST 2009

(I promise I won't prolong this any further than...)

Maybe is_float suffers from the same sematic issue as is_asfloat raised by 
Chris. Note that in Sendu's example, deeply is an adverb, so it suggests doing 
something, and float as a noun/adjective (in truth) suggests being something. 
So, what about
which suggests that this version of is() is described by float (float_is'ing 
rather than string_is'ing)

(I'm perfectly content with is_float, though)

----- Original Message ----- 
From: "Chris Fields" <cjfields at illinois.edu>
To: "Sendu Bala" <bix at sendu.me.uk>
Cc: "BioPerl List" <bioperl-l at lists.open-bio.org>; "Mark A. Jensen" 
<maj at fortinbras.us>
Sent: Sunday, January 18, 2009 5:51 PM
Subject: Re: [Bioperl-l] evalues/floating point tests

> On Jan 18, 2009, at 6:01 AM, Sendu Bala wrote:
>> Chris Fields wrote:
>>> is_float_eq()?
>> The 'is' obviates the need for the 'eq'. On the other hand there's  precedent 
>> for this, since is() actually calls is_eq().
> Yes, that's partly why I suggested it.  That's most descriptive of  what we 
> are doing with this method, 'is float $ev1 eq float $ev2'.
>>> On Jan 17, 2009, at 8:44 PM, Mark A. Jensen wrote:
>>>> how bout is_asfloat() ?
>> This is better. However...
> Sorry, no disrespect to you or Mark but I don't agree. 'Is as float'  doesn't 
> come across to me as an equality test, it almost sounds like a  role/interface 
> check.
>>> I thought the same thing at first, but (at least to me) is_float
>>> sounds more like a boolean test on whether the scalar value passed is
>>> a float rather than a comparison checking whether two floats are
>>> equal.
>> I understand that, but the naming convention is already like that. 
>> is_deeply() doesn't test if both values are 'deep', it tests if they  are 
>> 'is' (are equal) in a deep way. is_float() would test if they  are 'is' (are 
>> equal) in a float way. Yeah, grammatically it is all a  mess, but to me this 
>> seems the most consistent.
> I see what you're saying in this case.  We can go back to the simpler 
> is_float() if everyone agrees.  Just want to have something decided so  we can 
> move on.
>> The alternative, which may at the same time may be safer (the test  writer 
>> doesn't need to remember to use a special function) and more  dangerous (the 
>> regex matches something it shouldn't?), is to simply  override is():
>> my $e_num = '^\de-\d+$';
>> sub is {
>>    my ($val1, $val2, @args) = @_;
>>    if ($val1 && $val2 && $val1 =~ /$e_num/ && $val2 =~ /$e_num/) {
>>        $val1 = sprintf("%g", $val1);
>>        $val2 = sprintf("%g", $val2);
>>    }
>>    return SUPER::is($val1, $val2, @args);
>> }
>> Or something like that. I didn't try it.
> I understand the sentiment about extending is() but I'm not convinced  it 
> makes sense for a specific case such as this.  I agree with the  second 
> sentiment; extending is() may be more dangerous and prone to  subtle issues, 
> such as the regex above not matching '1.23e-12'. Yes, I  know, you didn't test 
> it. ;>
> And, if we ever change our minds it would be very easy to just  delegate to 
> is_float().
> $e_num = qr/something that matches just floats/;
> sub is {
>    my ($val1, $val2, @args) = @_;
>    if ($val1 && $val2 && $val1 =~ /$e_num/ && $val2 =~ /$e_num/) {
>        return is_float($val1, $val2, @args);
>    } else {
>        return SUPER::is($val1, $val2, @args);
>    }
> }
> chris
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