:orphan:

.. ****************************************************************************
.. CUI
..
.. The Advanced Framework for Simulation, Integration, and Modeling (AFSIM)
..
.. The use, dissemination or disclosure of data in this file is subject to
.. limitation or restriction. See accompanying README and LICENSE for details.
.. ****************************************************************************

.. _script_grammar:

Script Language Grammar
=======================

The following describes in detail the syntax allowed by the scripting language.  Users generally should not need to review this detail.

Character Types
---------------

::

  alpha = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz_".
  digit = "0123456789".
  cr  = '\r'.
  lf  = '\n'.
  tab = '\t'.
  quote = '"'.
  single_quote = "'".
  strchar = ANY - '"' - '\\' - '\n' - '\r'.
  chrchar = ANY - "'" - '\\' - '\n' - '\r'.

Tokens
------

::

  ident  = alpha {alpha | digit}.
  // numbers do not allow '+' or '-' as a prefix.
  // instead, they are handled as a unary operator
  number = digit {digit}.
  real_number = 
      (
       ( digit {digit} '.' {digit} )
              | ( '.' digit {digit} )
      ) [ ('e' | 'E') [ '-' | '+' ] digit {digit} ].

  // strchar does not include '\', so explicitly add '\' and '\"'
  string_literal = quote { strchar | ("\\" [ '"' ]) } quote.
  char_literal = "'" (chrchar | "\\'") "'".
  dot = ".".
  semicolon = ";".
  lparen = "(".
  rparen = ")".
  assign = "=".
  eq = "==".
  ne = "!=".
  ge = ">=".
  le = "<=".
  plus = "+".
  minus = "-".
  and = "&&".
  or = "||".
  rbrace = '}'.
  comma = ','.
  plus_assign = "+=".
  minus_assign = "-=".
  times_assign = "*=".
  div_assign = "/=".
  r_arrow = "->".
  do = "do".
  if = "if".
  for = "for".
  foreach = "foreach".
  in = "in".
  else = "else".
  while = "while".
  break = "break".
  continue = "continue".
  return = "return".
  null = "null".
  null2 = "NULL".
  true = "true".
  false = "false".

  string = "string".
  int = "int".
  double = "double".
  char = "char".
  bool = "bool".
  global = "global".
  static = "static".
  extern = "extern".

Comments
--------

::

   FROM "/*" TO "*/" NESTED
   FROM "//" TO end of line
   FROM "#" TO end of line

Productions
-----------

::

   // Syntax:
   // '[ ... ]'  - Optional Rules (match 0 or 1 time)
   // '{ ... }'  - Recurrence (match 0 to many times)
   // '( ... )'  - Rule grouping
   // |           - OR (match left rule or right rule)

   basic_type =
      string
    | int
    | double
    | char
    | bool
    .

   type
   =  basic_type
    | ident
    // Note: only allowing 1 or 2 template parameters
    [  '<' type [ ',' type ] '>' ]
    .

   trailer
   =  '('
         [ exp
            {
               ',' exp
            }
         ]
      ')'
    | ( '[' exp1 ']' [ '=' exp ] )
    | '.' ident
    | "->" ident
    .

   static_exp =
      (null | null2)
    | true
    | false
    | string_literal
    | char_literal
    | real_number
    | number
    .

   block = '{' {stat} '}'
    .
   block_func = {stat} EOF.

   extern_stat
   =  ( extern type ident )
        ( '('
           [ type [ident] { ',' type [ident] } ]
          ')' ';'
        )
        | ';'
    .

   var_decl_expr = type ident .

   var_decl
   =  [ static | extern | global ] type ident
         ['=' ( exp ) ]
         { ',' ident ['=' ( exp ) ] }
    .

   do_stat
   =  do stat while '(' bool_exp ')' ';'
    .
   while_stat
   = "while" '(' bool_exp ')' stat
    .
   bool_exp = exp 
    .
   stat
   =( 
      do_stat
    | while_stat
    | if '(' bool_exp ')'
         stat
       [ else stat ]
    | return [ exp ] ';'
    | break ';'
    | continue ';'
    | for '(' [ var_decl | assign_expr ] ';' exp ';' [assign_expr] ')'
         stat
    | foreach '(' var_decl_expr [ ':' var_decl_expr ] in exp ')'
         stat
    | block
    | extern_stat
    | stat2
    )
    .

   //stub:
   initializer_list
   ='{'
       [
         exp [ ':' exp ] { ',' exp [ ':' exp ] }
       ]
       [',']   // allow final ','
    '}'
    .

   AssignOp = "=" | "+=" | "-=" | "*=" | "/="
    .
   assign_expr =  identifier AssignOp exp
    .

   stat2
   =  var_decl ';'
    | assign_expr ';'
    | exp ';'
    .

   exp = exp1.
   exp1 = exp2 { or exp2 }
    .
   exp2 = exp3 { and exp3 }
    .
   exp3 = exp_eq { '^' exp_eq }
    .
   EqOp = ( "==" | "!=")
    .
   exp_eq = exp_test { EqOp exp_test }
    .
   TestOp = '<' | '>' | "<=" | ">=" 
    .
   exp_test =  exp_add { TestOp exp_add }
    .
   AddOp = '+' | '-' 
    .
   exp_add = exp_mult { AddOp exp_mult }
    .
   MulOp = '*' | '/'
    .
   exp_mult = exp5 { MulOp exp5 }
    .
   exp5 = 
      '(' type ')' exp5
    | '!' exp5
    | exp6
    .
   exp6 =  [( "+" | "-" ) ] exp7
    .
   exp7 = atom { trailer }
    .
   identifier = ident
    .
   atom
   =  '(' exp1 ')'
    | static_exp
    | type 
            '.' ident
          | '(' [ exp { ',' exp } ] ')'
    | identifier
    | initializer_list
    .

   formal_param_list
      = '(' [ type ident { ',' type ident } ] ')'
    .

   func_def =
      type ident
         formal_param_list
         block_func
    .