Great stuff. I’m equally intrigued by the `use fn` pragma: It allows one to selectively break compatibility.
Caveat: This kind of pragma introduces a lot of new complexity. Pragmas would indeed become less burdensome if one could configure them on a per-project basis. It corresponds to Eclipse setting different Java versions per source directory. Ideas (not sure that they are worth the added complexity, but wanted to mention them): - Meta-tag points to file that configures pragmas based on paths - Custom, user-defined meta-pragmas that group several pragmas - A pragma that points to a file with several pragmas On Jan 21, 2012, at 11:09 , Claus Reinke wrote: > From the Haskell experience again: there, one can have language > feature options > > - as pragmas in source code [1] > - as options in package descriptor files [2] > > The former is better for source readability, and for being specific > about which files depend on which extensions. The latter is better > for avoiding repetition if every source in a package uses the same > set of options, and for package readability (making package > feature dependencies obvious without having to scan source files). > In-source pragmas override package-wide options. > > One thing that Haskell doesn't have, which I have often wanted, > is the ability to define extension groups on a per-project basis: > > if I always use the same sets of extensions (eg, yield and block > scoping, or modules and classes, or ..), then it would be nice > to define pragma groups in the package file, and just refer to > the group pragma in the source files. That way, use of language > features would be explicit in the source, but without repetitive > details. However, this is less of an issue in JS than in Haskell > (the latter has far more language extensions, with a very > conservative base standard, while all ES extensions currently > under discussion will be grouped in ES6). > > Claus > > [1] http://www.haskell.org/ghc/docs/latest/html/users_guide/pragmas.html > [2] "extensions: identifier list" > A list of Haskell extensions used by every module. > Extension names are the constructors of the Extension type. > > http://hackage.haskell.org/packages/archive/Cabal/1.6.0.3/doc/html/Language-Haskell-Extension.html -- Dr. Axel Rauschmayer [email protected] home: rauschma.de twitter: twitter.com/rauschma blog: 2ality.com _______________________________________________ es-discuss mailing list [email protected] https://mail.mozilla.org/listinfo/es-discuss
