Added expression sequences to macro expander.

[scheme.forth.jl.git] / README.md

diff --git a/README.md b/README.md
index a435f53..52b4b6f 100644 (file)
--- a/README.md
+++ b/README.md
@@ -9,7 +9,7 @@ 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 also includes variadic compound function support, mark-sweep
-garbage collection, quasiquotation, and a very basic (non-hygenic) macro
+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
@@ -18,6 +18,89 @@ In future, I plan to also implement a more complete numerical tower to bring it
 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
 is included in this repository in the file COPYING.