Wow! This is awesome, nice work fogus! Ambrose
On Sat, Apr 7, 2012 at 1:55 AM, Fogus <mefo...@gmail.com> wrote: > What it is > ---------- > > Trammel is a [Clojure](http://clojure.org) providing contracts > programming (sometimes called "[Design by Contract]( > http://en.wikipedia.org/wiki/Design_by_Contract)" or DbC) capabilities. > Features of Trammel currently include: > > * Contracts on functions > * Composable contracts > * Post-definition function contract application > * defrecord and deftype invariants > * Reference type invariants (i.e. Agents, Atoms, Refs, and Vars) > * Ability to turn-off checks in a production setting > * Support for Clojure versions 1.3 and 1.4 > > Trammel is inspired by [Eiffel](http://www.eiffel.com/) and [Racket > Scheme](http://docs.racket-lang.org/reference/contracts.html). > > Absorb > ------ > > You can use Trammel in your [Leiningen]( > https://github.com/technomancy/leiningen) and [Cake]( > https://github.com/flatland/cake) projects with the following > `:dependencies` directive in your `project.clj` file: > > [trammel "0.7.0] > > For Maven-driven projects, use the following slice of XML in your > `pom.xml`'s `<dependencies>` section: > > <dependency> > <groupId>org.clojure</groupId> > <artifactId>trammel</artifactId> > <version>0.7.0</version> > </dependency> > > Enjoy! > > > Places > ------ > > * [Source code](https://github.com/fogus/trammel) > * [Ticket system](https://github.com/fogus/trammel/issues) > * [Examples and documentation](http://fogus.github.com/trammel/) -- in > progress > * [Dream Date](http://github.com/fogus/dream-date) - an example project > using Trammel -- in progress > > Changes from version 0.6.0 > -------------------------- > > * Better assertion error reporting > * Ability to add constraint descriptions used in assertion reporting > * Constrained defrecords no longer support default field values > * Constrained defrecords no longer generate keyword args ctor function > * Reference type invariants > > Reference type invariants work in the following ways. > > ### Atoms > > Atoms are created directly with their invariants: > > > > (def a (constrained-atom 0 > "only numbers allowed" > [number?])) > > @a > ;=> 0 > > > > And checked on change: > > > > (swap! a inc) > ;=> 1 > > > > Invariant violations are reported right away: > > > > (swap! a str) > ; Pre-condition failure: only numbers allowed > > (compare-and-set! a 0 "a") > ; Pre-condition failure: only numbers allowed > > > ### Refs > > Refs are created directly with their invariants: > > > > (def r (constrained-ref 0 > "only numbers allowed" > [number?])) > > > > And also checked on change, within a transaction: > > > > (dosync (alter r inc)) > ;=> 1 > > (dosync (alter r str)) > ; Pre-condition failure: only numbers allowed > > > > ### Vars > > Vars are created directly with their invariants: > > > > (defconstrainedvar ^:dynamic foo 0 > "only numbers allowed in Var foo" > [number?]) > > > > Var invariants are checked on rebinding, such as with `binding`: > > > > (binding [foo :a] [foo]) > ; Pre-condition failure: only numbers allowed > > > > ### Agents > > Agents are created directly with their invariants: > > > > (def ag (constrained-agent 0 > "only numbers allowed" > [number?])) > > > > And are checked on `send` and `send-off` > > (send ag str) > (agent-error ag) > > However, the invariant violations are reported consistently with the agent > setup. In this case, the errors are accessible via the `agent-error` > function. > > > Plans > ----- > > The following capabilities are under design, development, or consideration > for future versions of Trammel: > > - Contracts for higher-order functions > - Better error messages > - `defconstraint` -- with ability to relax requires and tighten ensures > - Modify macros to also allow regular Clojure constraint maps > - Allow other stand-alones: true/false, numbers, characters, regexes > - Marrying test.generative with Trammel > - More documentation and examples > > More planning is needed around capabilities not listed nor thought of. > > -- > You received this message because you are subscribed to the Google > Groups "Clojure" group. > To post to this group, send email to clojure@googlegroups.com > Note that posts from new members are moderated - please be patient with > your first post. > To unsubscribe from this group, send email to > clojure+unsubscr...@googlegroups.com > For more options, visit this group at > http://groups.google.com/group/clojure?hl=en -- You received this message because you are subscribed to the Google Groups "Clojure" group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en
