Complete reworking of the REPL

which is good in itself, but not what I was meant to be working on.

lisp/expt.lisp

@@ -0,0 +1,6 @@
+(set! expt (lambda
+            (n x)
+            "Return the value of `n` raised to the `x`th power."
+            (cond
+              ((= x 1) n)
+              (t (* n (expt n (- x 1)))))))

lisp/types.lisp

@@ -0,0 +1,24 @@
+(set! cons? (lambda (o) "True if o is a cons cell." (= (type o) "CONS") ) )
+(set! exception? (lambda (o) "True if o is an exception." (= (type o) "EXEP")))
+(set! free? (lambda (o) "Trus if o is a free cell - this should be impossible!" (= (type o) "FREE")))
+(set! function? (lambda (o) "True if o is a compiled function." (= (type o) "EXEP")))
+(set! integer? (lambda (o) "True if o is an integer." (= (type o) "INTR")))
+(set! lambda? (lambda (o) "True if o is an interpreted (source) function." (= (type o) "LMDA")))
+(set! nil? (lambda (o) "True if o is the canonical nil value." (= (type o) "NIL ")))
+(set! nlambda? (lambda (o) "True if o is an interpreted (source) special form." (= (type o) "NLMD")))
+(set! rational? (lambda (o) "True if o is an rational number." (= (type o) "RTIO")))
+(set! read? (lambda (o) "True if o is a read stream." (= (type o) "READ") ) )
+(set! real? (lambda (o) "True if o is an real number." (= (type o) "REAL")))
+(set! special? (lambda (o) "True if o is a compiled special form." (= (type o) "SPFM") ) )
+(set! string? (lambda (o) "True if o is a string." (= (type o) "STRG") ) )
+(set! symbol? (lambda (o) "True if o is a symbol." (= (type o) "SYMB") ) )
+(set! true? (lambda (o) "True if o is the canonical true value." (= (type o) "TRUE") ) )
+(set! write? (lambda (o) "True if o is a write stream." (= (type o) "WRIT") ) )
+
+(set! or (lambda values
+                 "True if any of `values` are non-nil."
+                 (cond ((car values) t) (t (apply 'or (cdr values))))))
+
+(set! number?
+      (lambda (o)
+              "I don't yet have an `or` operator