[I18n-sig] Strawman Proposal: Smart String Test
Fri, 09 Feb 2001 11:26:07 +0100
Paul Prescod wrote:
> The types module will contain a new function called
> types.isstring returns true if the object could be directly interpreted
> as a string. This is defined as: "implements the string interface and is
> compatible with the re regular expression engine."
re compatibility is given by read buffer compatibility; it is
not restricted to strings. In fact re works on buffers and mmap'ed
> At the moment no user
> types fit this criteria so there is no mechanism for extending the
> behavior of the types.isstring function yet. It's initial behavior is:
> def isstring(obj):
> return type(obj) in (StringType, UnicodeType)
Looks like a hack which would only serve a temporary need...
The right thing to do would be to add a
new abstract string type object and then have isinstance()
return 1 for StringType and UnicodeType when asked for the
new abstract type.
The problem with this approach is that we would be constructing
a forward compatible mechanism before having designed the
class hierarchie (see my other post) for these types, e.g.
binary data string (BinaryDataType)
text data string (TextDataType)
Unicode string encoded 8-bit string (with encoding
(UnicodeType) (StringType) information !)
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