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[Python-Dev] String views (was: Re: Proof of the pudding:str.partition())

Fredrik Lundh fredrik at pythonware.com
Thu Sep 1 08:40:19 CEST 2005 
skip at pobox.com wrote:

> As a Python programmer I'd get back what look like three strings: "http",
> ":", and "//www.python.org/".  If each of them was a view onto part of the
> original string, only the last one would truly refer to a NUL-terminated
> sequence of characters.  If I then wanted to see what scheme's value
> compared to, the string's comparison method would have to recognize that 
> it
> wasn't truly NUL-terminated, copy it, call strncmp() or whatever 
> underlying
> routine is used for string comparisons.  (Maybe string comparisons are 
> done
> inline.  I'm sure there are some examples where the underlying C string
> routines are called.)

Python strings are character buffers with a known length, not 
null-terminated C
strings.  the CPython implementation guarantees that the character buffer 
has a
trailing NULL character, but that's mostly to make it easy to pass Python 
strings
directly to traditional C API:s.

(string views are nothing new in Python.  the original Unicode string
implementation supported this, but that was partially removed during
integration.  the type still uses a separate buffer to hold the characters,
though (unlike 8-bit strings that store the characters in the string object
itself))

</F>
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