>> If you haven't yet read http://www.python.org/dev/peps/pep-3101/ (Advanced >> String Formatting) I suggest you do - its well worth a read and feels like a >> possible very javascripty solution. > > I have not read it. Thanks for the link. It has a good summary of > alternate syntaxes and establishes a point partway between positional > and inline syntax. It does include a bunch of format specifiers that > I think incompatible with DSL schemes.
I also like Python 3's string formatting design. But it makes me wonder -- how much of the quasi-literal proposal can be done in a library? I think basically all of string formatting could be implemented as a library in Python 2 -- you just need to implement your own .format() method on strings. JSON Template was explicitly designed to be "upwardly compatible" with Python 3k string formatting: http://code.google.com/p/json-template/ Here's how you would embed HTML: '{name|html}: <a href="{url|html-attr-value}">{anchor|html}</a>' where html escapes <>& and html-attr-value escapes <>&". You can set a default formatter for security: t = jsontemplate.Template('{name}: <a href="{url|html-attr-value}">{anchor}</a>', default_formatter='html') It's compiled into alternating literal strings and substitution nodes. I like the idea of "enabling DSLs", but I feel like this proposal is a DSL itself, rather than enabling them, since it has a fairly particular syntax, and you have defined the parse tree very specifically. Another Python analogy is that they chose not to embed regex's in the language, unlike JavaScript/Perl/Ruby. Instead there is a very minimal syntactic accomodation -- raw strings which don't have backslash escaping. The Go language takes this same approach with backticks I believe (e.g. `\s+` and not "\\s+"). I do think JavaScript really needs better string interpolation than "foo " + var + " bar", which unfortunately a common idiom. I think that perhaps all that would be necessary is to have a .format() method on strings, like Python. Python switched from the operator % to a simple method. Andy _______________________________________________ es-discuss mailing list es-discuss@mozilla.org https://mail.mozilla.org/listinfo/es-discuss
