=========================================
Juliet Programming Language Specification
Author....... Kevin P. Albrecht
Version...... 0.20
Date......... 15 Jan 2003
=========================================

-----------
IDENTIFIERS
-----------
Identifiers (variables, labels, etc.) must begin with one
of the follwing characters:

  abcdefghijklmnopqrstuvwxyz
  ABCDEFGHIJKLMNOPQRSTUVWXYZ_

The rest of the identifier can be any of the characters
below:

  0123456789
  abcdefghijklmnopqrstuvwxyz
  ABCDEFGHIJKLMNOPQRSTUVWXYZ_  

--------
ROUTINES
--------

there must be a main routine

routines are not recursive

rout NAME { :TYPE }
  CODE
  { return { EXP } }

-------
EXITING
-------
to immediately terminate the program, use the following statement

exit

-----
SCOPE
-----
scope is defined by indentation, as in python

  indent   example
  ------   -------
  0        printn "Hello, World!"
  5        {hi} printn "Hello!"
  5             c <- x 

variable names can be redefined in a deeper scope, which
  will hide the original definition of that variable.

-----
STACK
-----
push EXP
pop VARIABLE

---------------
FLOW OF CONTROL
---------------

#(identifier)		  line label
goto (identifier) goto the line labeled with (identifier)

loop BOOLEAN_EXP
  BLOCK

cond _boolean_exp_
  _block_

--------------
FILE INCLUSION
--------------
$filename.jul
  inserts the Juliet file immediately
  filename can be omitted

-----------
CONSOLE I/O
-----------
(items in {} are optional):

print { EXP }
printn { EXP }

cinput
  a special string identifier that grabs a string out of the console

--------------------
VARIABLE DEFINITIONS
--------------------
Variables are automatically initialized as follows:
  int: 0
  rat: 0.0
  str: ""

Variables cannot be used in the same statement they are defined in.

Variables are defined as follows (items in {} are optional):
  def ID:TYPE { <- EXP } { , ID:TYPE { <- EXP } } { , ... }
  where TYPE = int, rat, or str

Constants are defined as follows:
  const ID:TYPE <- EXP { , ID:TYPE <- EXP }

------------
TYPE CASTING
------------

int EXP
rat EXP
str EXP

--------
COMMENTS
--------

{{ single line

{ multiple line }

--------
LITERALS
--------
String:   "Hello", "23.4"
Integer:  23, -1000
Rational: 23.0

'nl' is a special string variable that contains the newline value
Rationals can store up to 6 digits in the mantissa (to the
  right of the decimal point).

-------------------
ASSIGNMENT OPERATOR
-------------------

a <- b
  where a = variable
        b = expression

---------------
LOGIC OPERATORS
---------------

a = b
a <> b
  (a=num & b=num) | (a=str & b=str)
  yields: rat

a < b
a > b
a <= b
a >= b
a or b
a and b
  a=num & b=num
  yields: rat

--------------------
ARITHMETIC OPERATORS
--------------------

a + b
a - b
a * b
a / b
  a=num & b=num
  yields: if (a|b = rat) then rat
          else                int

a mod b
  a=int & b=int
  yields: int

a ^ b
  a=num & b=int
  yeilds: if a=rat, then rat
          if a=int, then int

---------------
STRING OPERATOR
---------------

a & b
  a=str & b=str
  yields: str