Welcome to the PWhile-TensorFlow Compiler!

This compiler will interprets the probabilistic programming languages `Probabilistic While', pWhile in short, into the newly developing Python library TensorFlow!

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[HOW TO RUN THE COMPILER IN TERMINAL]

1. modify the `compile' file as follows:
   $ java -cp [D1]:[D2]:...:[Dn] pwCompiler.Main $1
   $ exit $?
   where [D1], [D2], ..., [Dn] should be replaced by file paths of all dependencies of Java, separated by semicolons. 

2. open a terminal, and then go to "pwhile" directory

3. to compile:
> make

4. set up ruby frontend:
> #!/usr/bin/env ruby
> chmod +x compile

5. to run the compiler:
> ./compile filename.pw

6. to run the output program: (make sure you have Python and TensorFlow installed)
> python filename.py

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[PWHILE'S MAIN SYNTAX]

stat  : SKIPP                                   #skip
      | STOP                                    #stop
      | IDENT DECLARE valueRange                #declareVariable
      | IDENT ASSIGN expr                       #assignment
      | IDENT RDASSIGN valueRange               #randomAssignment
      | IF expr THEN stat ELSE stat FI          #if
      | WHILE expr DO (OPEN_SQUARE_BRACKET INTEGER CLOSE_SQUARE_BRACKET)? (OPEN_SQUARE_BRACKET LT pr CLOSE_SQUARE_BRACKET)? (OPEN_SQUARE_BRACKET IDENT COMMA pr COMMA IDENT CLOSE_SQUARE_BRACKET)? stat OD  #while
      | CHOOSE pr DECLARE stat (ORR pr DECLARE stat)+ RO   #choose
      | IDENT binOpP2 SEQ pr                     #paraInc
      | stat SEMICOLON stat                     #statlist
;

expr  : INTEGER                                 #integer
      | BOOL                                    #bool
      | IDENT                                   #identifier
      | expr binOpP1 expr                       #binOp1Expr
      | expr binOpP2 expr                       #binOp2Expr
      | expr binOpP3 expr                       #binOp3Expr
      | expr binOpP4 expr                       #binOp4Expr
      | expr binOpP5 expr                       #binOp5Expr
      | expr binOpP6 expr                       #binOp6Expr
      | unaryOp expr                            #unaryOpExpr
      | OPEN_PARENTHESES expr CLOSE_PARENTHESES #nestedExpr
;

pr    : INTEGER DIV INTEGER  #fraction
      | MINUS? DOT INTEGER   #decimal
      | INTEGER              #oneOrZero
      | IDENT                #prVar
;

valueRange: OPEN_CURLY_BRACKET (expr(COMMA expr)*)? CLOSE_CURLY_BRACKET
          | OPEN_CURLY_BRACKET INTEGER DDOT INTEGER CLOSE_CURLY_BRACKET
;

para: PARA (IDENT DECLARE OPEN_SQUARE_BRACKET pr COMMA pr COMMA pr CLOSE_SQUARE_BRACKET)+ IDENT;

prog: (para)* VAR stat SEMICOLON BEGIN stat SEMICOLON END EOF;

##See ./src/pWhile.g4 for more details

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[EXAMPLE PWHILE PROGRAM]

#######################
##  PARAMETER STAGE  ## 
#######################
## For each time, take (p, q) as (0.0, 1.0), (0.1, 0.9), (0.2, 0.8), ..., (1.0, 0.0)
para
  p : [0, 1, 10]     
  q
#########################
##  DECLARATION STAGE  ## 
#########################
## Declare a's variable scope
var
  a : {1..10};
##########################
##  MAIN PROGRAM STAGE  ## 
##########################
## randomly assign `a' a value
begin
  choose p: a ?= {1..5} or q: a ?= {6..10} ro;
  stop;
end