From 6853c6c29c14c418bd23db9247412cfbf6a9931d Mon Sep 17 00:00:00 2001
From: Simon Brooke <simon@journeyman.cc>
Date: Wed, 14 Aug 2019 20:41:45 +0100
Subject: [PATCH] Added the bones of EVAL; tried to make cons-cell Seqable -
failed
---
README.md | 36 +++++++++++++++++++-----------------
src/beowulf/cons_cell.clj | 19 ++++++++++++++++++-
src/beowulf/eval.clj | 25 +++++++++++++++++++++++++
3 files changed, 62 insertions(+), 18 deletions(-)
create mode 100644 src/beowulf/eval.clj
diff --git a/README.md b/README.md
index 190505d..31efe93 100644
--- a/README.md
+++ b/README.md
@@ -2,31 +2,33 @@
LISP 1.5 is to all Lisp dialects as Beowulf is to Emglish literature.
+## What this is
+
+A work-in-progress towards an implementation of Lisp 1.5 in Clojure.
+
+## BUT WHY?!!?!
+
+Because.
+
+Because Lisp is the only computer language worth learning, and if a thing is worth learning, it's worth learning properly; which means going back to the beginning and trying to understand that.
+
+Because there is, so far as I know, no working implementation of Lisp 1.5 for modern machines.
+
+Because I'm barking mad, and this is therapy.
+
## Installation
Download from http://example.com/FIXME.
## Usage
-FIXME: explanation
+`java -jar beowulf-0.1.0-standalone.jar`
- $ java -jar beowulf-0.1.0-standalone.jar [args]
+## Learning Lisp 1.5
-## Options
-
-FIXME: listing of options this app accepts.
-
-## Examples
-
-...
-
-### Bugs
-
-...
-
-### Any Other Sections
-### That You Think
-### Might be Useful
+The `Lisp 1.5 Programmer's Manual` is still
+[in print, ISBN 13 978-0-262-13011-0](https://mitpress.mit.edu/books/lisp-15-programmers-manual); but it's also
+[available online](http://www.softwarepreservation.org/projects/LISP/book/LISP%201.5%20Programmers%20Manual.pdf).
## License
diff --git a/src/beowulf/cons_cell.clj b/src/beowulf/cons_cell.clj
index b54a915..8139bc4 100644
--- a/src/beowulf/cons_cell.clj
+++ b/src/beowulf/cons_cell.clj
@@ -3,7 +3,24 @@
(def NIL (symbol "NIL"))
-(deftype ConsCell [CAR CDR])
+(deftype ConsCell [CAR CDR]
+ clojure.lang.ISeq
+ (cons [this x] (ConsCell. x this))
+ (count [this] (if
+ (= (.CDR this) NIL)
+ 0
+ (inc (count (.CDR this)))))
+ (first [this] (.CAR this))
+ (more [this] (if
+ (= (.CDR this) NIL)
+ clojure.lang.PersistentList/EMPTY
+ (.CDR this)))
+ (next [this] (.CDR this))
+ (seq [this] this) ;; doesn't work - `Method beowulf/cons_cell/ConsCell.seq()Lclojure/lang/ISeq; is abstract`
+
+ clojure.lang.IPersistentCollection
+ (empty [this] false)
+ (equiv [this other] false))
(defn make-cons-cell
[a d]
diff --git a/src/beowulf/eval.clj b/src/beowulf/eval.clj
new file mode 100644
index 0000000..22afe71
--- /dev/null
+++ b/src/beowulf/eval.clj
@@ -0,0 +1,25 @@
+(ns beowulf.eval
+ (:require [beowulf.cons-cell :refer [make-beowulf-list make-cons-cell NIL]]))
+
+(declare *oblist* primitive-eval)
+
+
+
+(defn primitive-eval
+ [x]
+ (cond
+ (number? x) x
+ (symbol? x) (@*oblist* x)
+ (instance? x beowulf.cons_cell.ConsCell)
+ (apply (primitive-eval (.CAR x)) (map primitive-eval (.CDR x)))
+ :else
+ (throw (Exception. (str "Don't know how to eval `" x "`")))))
+
+
+(def ^:dynamic *oblist*
+ "The base environment."
+ (atom {'NIL NIL
+ 'F NIL
+ 'T 'T
+ 'eval primitive-eval}))
+