Ben Wolfson wrote: > Hi, > > I'm hoping to get some kind of consensus about the divergences between > the implementation and documentation of str.format > (http://mail.python.org/pipermail/python-dev/2011-June/111860.html and > the linked bug report contain examples of the divergences). These > pertain to the arg_name, attribute_name, and element_index fields of > the grammar in the docs: > > replacement_field ::= "{" [field_name] ["!" conversion] [":" > format_spec] "}" > field_name ::= arg_name ("." attribute_name | "[" > element_index "]")* > arg_name ::= [identifier | integer] > attribute_name ::= identifier > element_index ::= integer | index_string > index_string ::= <any source character except "]"> + > > Nothing definitive emerged from the last round of discussion, and as > far as I can recall there are now three proposals for what kind of > changes might be worth making: > > (1) the implementation should conform to the docs;* > (2) like (1) with the change that element_index should be changed to > "integer | identifier" (rendering index_string otiose); > (3) like (1) with the change that index_string should be changed to > '<any source character except "]", "}", or "{">'. > > * the docs link "integer" to > http://docs.python.org/reference/lexical_analysis.html#grammar-token-integer > but the current implementation only allows decimal integers, which > seems reasonable and worth retaining. > > (2) was suggested by Greg Ewing on python-dev and (3) by Petri > Lehtinen in the bug report. (Petri actually suggested that braces be > disallowed except for the nesting in the format_spec, but it comes to > the same thing.) > > None of these should be difficult to implement; patches exist for (1) > and (2). (2) and (3) would lead to format strings that are easier to > for the programmer to visually parse; (1) would make the indexing part > of the replacement field conform more closely to the way indexing with > strings behaves in Python generally, where arbitrary strings can be > used. (It wouldn't conform exactly, obviously, since ']' would still > be excluded.) > > I personally would prefer (1) to (2) or (3), and (3) to (2), had I my > druthers, but it doesn't matter a *whole* lot to me; I'd prefer any of > them to nothing (or to changing the docs to reflect the current batty > behavior).
+1 for changing. And as I've said before, I prefer proposal (3). _______________________________________________ Python-Dev mailing list Python-Dev@python.org http://mail.python.org/mailman/listinfo/python-dev Unsubscribe: http://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
