Easy way to implement this within an NFA->DFA framework:
When doing split on a regex, just 'and' the regular expression
together with .+ . For example, [0-9]* becomes ([0-9]*)&(.+) . DFA
minimization makes this just as efficient as [0-9]+ would have been,
which is what you really want.
Dan
On Sat, Oct 4, 2008 at 11:23 PM, Stefan Scholl <[EMAIL PROTECTED]> wrote:
> Hi Slava & Co.,
>
> Ruby and Perl do it this way:
>
>>> "sdfh923oweop23dfosdhf0sdofo".split(/[0-9]*/)
> => ["s", "d", "f", "h", "o", "w", "e", "o", "p", "d", "f", "o", "s", "d",
> "h", "f", "s", "d", "o", "f", "o"]
>
>
> Python goes another way:
>
>>>> re.split(r"[0-9]*", "sdfh923oweop23dfosdhf0sdofo")
> ['sdfh', 'oweop', 'dfosdhf', 'sdofo']
>
>
> Ruby and Perl split a string into the single characters when you
> just supply an empty string as pattern. Python ignores it.
>
>>> "Ruby".split("")
> => ["R", "u", "b", "y"]
>
>
>>>> re.split("", "Python")
> ['Python']
>
>
> I guess this feature is useful in Perl, because now you can
> easily iterate over the single characters of a string. This isn't
> needed for Ruby and Python.
>
> And Factor doesn't need to split strings into single characters,
> too.
>
> I'd say the Python way would be appropriate.
>
>
> Slava Pestov <[EMAIL PROTECTED]> wrote:
>> Hi Stefan,
>>
>> The problem is that [0-9]* matches an empty string. The fact that it
>> hangs is a bug, but what should be the appropriate behavior in this
>> case?
>>
>> Slava
>>
>> On Tue, Sep 30, 2008 at 4:08 AM, Stefan Scholl <[EMAIL PROTECTED]> wrote:
>>> Just testing re-split (vocab "regexp):
>>>
>>> USE: regexp
>>> "sdfh923oweop23dfosdhf0sdofo" "[0-9]*" <regexp> re-split
>>>
>>>
>>> And now Factor hangs. Process at full 50 % (dual cores are funny).
>>>
>>>
>>> Factor build 492, Windows XP.
>>>
>>>
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>
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>
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