[Python-3000] string.Formatter class (original) (raw)

Talin talin at acm.org
Thu Aug 30 09:03:30 CEST 2007

Eric Smith wrote:

Eric Smith wrote:

Jim Jewett wrote:

but you might want to take inspiration from the "tail" of an elementtree node, and return the field with the literal next to it as a single object.

(literaltext, fieldname, formatspec, conversion) I think I like that best. I implemented this in r57641. I think it simplifies things. At least, it's easier to explain.

Actually...I'm in the middle of writing the docs for the reference manual, and I'm finding this a little harder to explain. Not much harder, but a little bit.

I would probably have gone with one of the following:

# Test for str vs tuple
literal_text
(field_name, format_spec, conversion)

# Test for length of the tuple
(literal_text)
(field_name, format_spec, conversion)

# Test for 'None' format_spec
(literal_text, None, None)
(field_name, format_spec, conversion)

However, I'm not adamant about this - it's up to you what you like best, I'll come up with a way to explain it. Also I recognize that your method is probably more efficient for the nominal use case -- less tuple creation.

Also I wanted to ask: How about making the built-in 'format' function have a default value of "" for the second argument? So I can just say:

format(x)

as a synonym for:

str(x)

Due to an optimization dealing with escaped braces, it's possible for (literal, None, None, None) to be returned more than once. I don't think that's a problem, as long as it's documented. If you look at string.py's Formatter.vformat, I don't think it complicates the implementation at all.

It's also possible for the literal text to be an empty string if you have several consecutive format fields - correct?

Thanks for the suggestion.

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