grammer

prog ::= func |
func prog

func ::= function iden ( flist ) returns type : body end |

body ::= stmt |
stmt body

stmt ::= expr ; |

defvar ; |
if ( expr ) stmt |
if ( expr ) stmt else stmt |
while ( expr ) do stmt |
foreach ( iden of expr ) stmt |
return expr ; |
: body end

defvar ::= val type iden

expr ::= iden ( clist ) |
expr [ expr ] |
expr ? expr : expr |
expr = expr |
expr + expr |
expr - expr |
expr * expr |
expr / expr |
expr % expr |
expr < expr |
expr > expr |
expr == expr |
expr != expr |
expr <= expr |
expr >= expr |
expr || expr |
expr && expr |
! expr |
- expr |
+ expr |
( expr ) |
iden |
num

flist ::= |
type iden |
type iden , flist

clist ::= |
expr |
expr , clist

type ::= Int |
Array |
Nil

num ::= [0-9]+

iden ::= [a-zA-Z_][a-zA-Z_0-9]*


expr := 
expr [ expr ] |
expr ? expr : expr |
expr + expr |
expr - expr |
expr * expr |
expr / expr |
expr % expr |
expr < expr |
expr > expr |
expr == expr |
expr != expr |
expr <= expr |
expr >= expr |
expr || expr |
expr && expr |

expr1 := 

expr ::= iden ( clist ) |
! expr |
- expr |
+ expr |
( expr ) |
iden |
num
iden = expr |