1. To invoke MIT-Scheme interpreter on  paladin/discover/gamma: 
   type "scheme" to shell (Prompt: "csh>").

    csh> scheme

2. Typically a file containing Scheme function definitions is created
   prior to invoking the interpreter (Prompt "]=>").

   To load the file "EG.scm" containing the definitions use

   ]=>(load "EG.scm")

   Subsequently, the code can be tested by appropriate function calls.

   ]=>(cons 'a (list 1 ()))

3. To store the transcript of a complete session with the interpreter 
   in the file called "Test-Log", use the following commands:

   ]=>(transcript-on "Test-Log")

   ]=>(load "EG.scm")

   ]=>      ...

   ]=>(func arg1 ... argn)        ; TEST CASES

   ]=>      ...

   ]=>(transcript-off)

4. Scheme comments begin with ";" and go through end-of-line.
   (Cf. Java/C++ comments begin with "//" and go through end-of-line.
        Ada comments begin with "--" and go through end-of-line.)
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Note that the functionality of : "Is this an atom?" can be obtained by using 
the following related  predicates:        symbol?,  number?  etc

(symbol? 'a)           ; #t

(symbol? '(a b c))     ; ()

(number? 5)            ; #t 

(eq?  ()  #f)          ; #t

============================================================================
    "()" is interpreted as EMPTY-LIST in a list-context
     and is interpreted as FALSE in a boolean-context.
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The following pairs of expressions are NOT equal.

   (two+three)             (two + three)
   ; Blanks around + act as token separator.
 
   (two.three)             (two . three)
   ; LHS is a list containing an identifier, 
   ; RHS is a dotted pair.

  '( (a) )                '( a )
   ; parentheses in data adds a nesting level, and so are significant.

   ( append )              append
   ; parentheses in code adds a call to interpreter, and so are significant.