scheme-clojure

destruct.clj

(let [[fst & rst] (parse "(+ 1 1)")]
 [fst rst])
  --> [:+ (1.0 1.0)]

eval-apply.clj

(defn _eval [exp env]
  (cond
   ; self-evaluating?
   (or (number? exp) (string? exp) (fn? exp)) [exp env]

   ; var reference to be looked up in env
   (keyword? exp) [(lookup exp env) env]
   
   ; parsed combinations (function calls)
   (vector? exp) (let [[fst & rst] exp
                       [r e] (_eval fst env)]
                   (cond
                    ; built-in function calls
                    (fn? r) (_apply r rst e)
                    ; user defined function/lambda calls
                    (list? r) (let [[args body] r
                                    n (zipmap args (map #(get-evval % e) rst))
                                    new-env (cons n e)]
                                (_eval body new-env))  ; eval the first form only
                    :else [exp env]))
   :else (throw (Exception. (format "invalid interpreter state %s %s" (str exp) (str env))))))

(defn _apply [f args env]
  (f args env))

parsing-example.clj

(parse-all "foo bar")
  --> [:foo :bar]
(parse "12")
  --> 12.0
(parse "(+ 1 a)")
  --> [:+ 1.0 :a]

repl-example.clj

$ java -jar mtscheme-0.0.1-SNAPSHOT-standalone.jar 
mtscheme 0.1
nil
=> (define (foreach f l) (if (not (null? l)) (begin (f (car l)) (foreach f (cdr l)))))
nil
=> (foreach display (list 1 2 3))
1.0
2.0
3.0
nil
=> 

token-example.clj

(tokenize "(foo)")
  --> [[:open] [:symbol "foo"] [:close]]
(tokenize "\"foo\"")
  --> [[:string "foo"]]
(tokenize "12")
  --> [[:symbol "12"]]