The Racket repository
2ada6d0e89
- the `lam' structure from `compiler/zo-struct' changed to include a `toplevel-map' field This change helps solve a finalization problem in `racket/draw', which in turn sigificantly reduces the peak memory use of `raco setup' during the doc-building phase (because some documents load `racket/draw' to render images, and multiple copies of `racket/draw' were retained before finalization was fixed). The change is an extreme way to solve a specific finalization problem, but it's a kind of space-safety improvement; space safety almost never matters, but when it does, then working around a lack of space safety is practically impossible. In this case, it's not clear how to otherwise solve the `racket/draw' finalization problem. The improvement doesn't change the representation of closures, but it requires special cooperation with the GC. All closures in a module continue to share the same array of globals (plus syntax objects); that is, instead of completely flat closures, Racket uses a two-level environment where top-/module-level variables are grouped together. The code half of a closure now records which top-/module-level variables the body code actually uses, and the mark phase of GC consults this information to retain only parts of the top-/module-level environment frame that are actually used by some closure (or all of the frame if it is accessible through some other route). In other words, the GC supports a kind of "dependent reference" to an array that is indexed by positions into the array --- except that the code is more in the "Racket" directory instead of the "GC" directory, since it's so specific to the closure representation. |
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| README | ||
The Racket programming language =============================== Important executables: * DrRacket: Racket's integrated development environment (start here!). * Racket: the main command-line entry point for running racket programs and scripts. * GRacket: the GUI-mode Racket executable. * raco: Racket's command-line toolset. More Information ---------------- Racket comes with extensive documentation: use DrRacket's `Help' menu, or run `raco docs'. Also, visit us at http://racket-lang.org/ for more Racket resources. Instructions for building Racket from source are in src/README. License ------- Racket Copyright (c) 2010-2011 PLT Scheme Inc. Racket is distributed under the GNU Lesser General Public License (LGPL). This means that you can link Racket into proprietary applications, provided you follow the rules stated in the LGPL. You can also modify Racket; if you distribute a modified version, you must distribute it under the terms of the LGPL, which in particular means that you must release the source code for the modified software. See doc/release-notes/COPYING.LIB for more information.