X-Git-Url: https://thelambdalab.xyz/gitweb/index.cgi?p=scheme.forth.jl.git;a=blobdiff_plain;f=README.md;h=52b4b6f24b36316f15b9967c61e12af5a018d56b;hp=1dcb17d7e40ef2a2302788632a5567689df257e4;hb=6c019df6b459c86bf5de4fd817db2316038935da;hpb=e2e8c8f6d1d43e1044b91080f4cd3922fcd99472 diff --git a/README.md b/README.md index 1dcb17d..52b4b6f 100644 --- a/README.md +++ b/README.md @@ -1,15 +1,105 @@ scheme.forth.jl --------------- -A hobby scheme interpreter for FORTH 83. Specifically it is targeted at -[forth.jl](http://github.com/tgvaughan/forth.jl) which is an implementation -of FORTH on top of [Julia](http://www.julialang.org), hence the name. -At the moment it is a fairly direct port of Peter Micheaux's [Bootstrap +A hobby Scheme interpreter for FORTH 83. Specifically it is targeted at +[forth.jl](http://github.com/tgvaughan/forth.jl) which is an implementation of +FORTH on top of [Julia](http://www.julialang.org), hence the name. It began +life as a fairly direct port of Peter Micheaux's [Bootstrap Scheme](https://github.com/petermichaux/bootstrap-scheme) (as described in -[this wonderful series of blog posts](http://peter.michaux.ca/articles/scheme-from-scratch-introduction)) -from C to forth, but I plan to go a bit beyond this by implementing some -nice features like garbage collection, macros and a more complete numerical -tower to bring it closer to [R5RS](http://www.schemers.org/Documents/Standards/R5RS/). +[this wonderful series of blog +posts](http://peter.michaux.ca/articles/scheme-from-scratch-introduction)) from +C to forth, but also includes variadic compound function support, mark-sweep +garbage collection, quasiquotation, and a basic (non-hygienic) macro +system. + +In future, I plan to also implement a more complete numerical tower to bring it closer to +[R5RS](http://www.schemers.org/Documents/Standards/R5RS/). + +The goal is for the interpreter to be complete enough to be used to complete +the majority of the exercises found in [SICP](http://sarabander.github.io/sicp/). + +Running the interpreter +======================= + +To run this Scheme interpreter, first open Julia from the src directory contained +in this repository. If you've not done so already, install forth.jl using the +following command: + + julia> Pkg.clone("https://github.com/tgvaughan/forth.jl") + +Then, import and run the Forth system: + + julia> import forth + julia> forth.run() + Welcome to forth.jl! + +Once Forth is running, execute the Scheme source and fire up the +REPL using the following commands: + + include scheme.4th ok + scheme repl + Welcome to scheme.forth.jl! + Use Ctrl-D to exit. + + > + +At this point you can start entering Scheme commands. For example, + + > (define (factorial n) + (if (= n 0) + 1 + (* n (factorial (- n 1))))) + ; ok + > (factorial 5) + ; 120 + +Metacircular Evaluator +====================== + +Of course, one of the things you can do in Scheme (or of course any programming +language, this is the fundamental thing) is implement an interpreter for +another programming language. The examples directory in this repository +contains a verbatim copy of the source for the "metacircular" scheme interpreter +from SICP. To load it, use the following command: + + > (load "../examples/metacirc.scm") + ; ok + +Be prepared to wait a couple of minutes. When the interpreter finally loads, enter +the following command to run it: + + > (driver-loop) + +You'll then be greeted by the following prompt: + + ;; M-Eval input: + +At this point you can start entering Scheme commands... but be prepared to wait +a _long_ time for the result. For instance, the following example from SICP +defines and demonstrates a recursive list append procedure: + + (define (append x y) + (if (null? x) + y + (cons (car x) + (append (cdr x) y)))) + + ;;; M-Eval value: + ok + + ;;; M-Eval input: + (append '(a b c) '(d e f)) + + ;;; M-Eval value: + (a b c d e f) + +Be prepared to wait 20 min or more for the final result to be printed. (Given +that at this point we have a program running in a Scheme interpreter running +inside another Scheme interpreter which is itself running on a Forth system +that is implemented in Julia, this should not be a surprise.) + +License +======= This software is free (as in freedom) and is distributed under the terms of version 3 of the GNU General Public License. A copy of this license