- Racket's macro expander uses a new representation of binding called
"set of scopes". The new binding model provides a simpler
explanation of how macros preserve binding, especially across module
boundaries and in hygiene-bending expansions. The new expander is
mostly compatible with existing Racket macros, but there are some
incompatibilities. For the formally inclined, a research paper on
this macro system will appear at POPL next year:
- Racket's GUI library now uses Gtk+ 3 when available, instead of Gtk+
2. Set the `PLT_GTK2` environment variable to select Gtk+ 2.
- Added a new Redex tutorial based on a week-long workshop in SLC.
- Better syntax error checking for Redex patterns that do not use
- The blueboxes are more agressive about finding names to look up in
the docs, meaning they are useful much more often.
- Submodules are now fully supported in Typed Racket. Previously, some
uses of submodules would produce internal errors, making it hard to
`module+ test` and `module+ main` effectively in Typed Racket. The
switch to the set-of-scopes expander fixed these problems, and
submodules are now happily at home in Typed Racket.
- The `typed/racket/unsafe` library provides import and export forms
that circumvent contract generation. This improves performance for
typed-untyped interaction at the cost of safety and debuggability.
- Typed Racket provides experimental support for units (from
- The experimental `define-new-subtype` form allows overlaying finer
distinctions between otherwise identical types, similar to Haskell's
- The `Promise` type constructor changes in a backwards-imcompatible
way to exclude promises created with `promise/name`.
- The `unstable-*` packages are out of the main distribution. Most of
their contents have been either merged with established Racket
libraries or spun off as their own packages. This change is
backwards compatible for packages that properly list their
dependencies. Full details:
- edu: `big-bang` supports a display-mode clause so that world
programs can take over the entire screen.