//----------------------------------------------------------------------
// Global Declarations
//----------------------------------------------------------------------

program         := file+

file            := newline? (declr newline)* func*


declr           := typedef | globals | native_func

typedef         := 'type' id 'extends' ('handle' | id) 

globals         := 'globals' newline global_var_list 'endglobals' 

global_var_list := ('constant' type id '=' expr newline 
                   | var_declr newline)*

native_func     := 'constant'? 'native' func_declr

func_declr      := id 'takes' ('nothing' | param_list) 
                   'returns' (type | 'nothing')

param_list      := type id (',' type id)*

func            := 'constant'? 'function' func_declr newline 
                   local_var_list statement_list 'endfunction' newline

//----------------------------------------------------------------------
// Local Declarations
//----------------------------------------------------------------------

local_var_list  := ('local' var_declr newline)*

var_declr       := type id ('=' expr)? | type 'array' id 

//----------------------------------------------------------------------
// Statements
//----------------------------------------------------------------------

statement_list  :=  (statement newline)*

statement       := set | call | ifthenelse | loop | exitwhen | return 
                   | debug

set             := 'set' id '=' expr | 'set' id '[' expr ']' '=' expr 

call            := 'call' id '(' args? ')'

args            := expr (',' expr)*

ifthenelse      := 'if' expr 'then' newline statement_list 
                   else_clause? 'endif' 

else_clause     := 'else' newline statement_list 
                   | 'elseif' expr 'then' newline statement_list
else_clause?

loop            := 'loop' newline statement_list 'endloop'

exitwhen        := 'exitwhen' expr 
                // must appear in a loop

return          := 'return' expr?

debug           := 'debug' (set | call | ifthenelse | loop)

//----------------------------------------------------------------------
// Expressions
//----------------------------------------------------------------------

expr            := binary_op | unary_op | func_call | array_ref | func_ref 
                   | id | const | parens

binary_op       := expr ([+-*/><]|'=='|'!='|'>='|'<='|'and'|'or') expr

unary_op        := ('+'|'-'|'not') expr
                // expr must be integer or real when used with unary '+'

func_call       := id '(' args? ')'

array_ref       := id '[' expr ']'

func_ref        := 'function' id

const           := int_const | real_const | bool_const | string_const | 'null'

int_const       := decimal | octal | hex | fourcc

decimal         := [1-9][0-9]*

octal           := '0'[0-7]*

hex             := '$'[0-9a-fA-F]+ | '0'[xX][0-9a-fA-F]+

fourcc          := ''' .{4} '''

real_const      := [0-9]+'.'[0-9]* | '.'[0-9]+

bool_const      := 'true' | 'false'

string_const    := '"' .* '"'
                // any double-quotes in the string must be escaped with \

parens          := '(' expr ')'

//----------------------------------------------------------------------
// Base RegEx
//----------------------------------------------------------------------

type            := id | 'code' | 'handle' | 'integer' | 'real' | 'boolean' 
                   | 'string'

id              := [a-zA-Z]([a-zA-Z0-9_]* [a-zA-Z0-9])?

newline         := '\n'+