Expressions

The grammar rules for an expression are, in order of precedence, from high to low (note $\epsilon$ stands for the empty string):

		 expr::				        id

$\vert$		 number

$\vert$		 { atom,$\ldots$,atom }

$\vert$		 expr :: expr

$\vert$		 [-$\vert$+$\vert$*$\vert$&$\vert$|$\vert$^] expr

$\vert$		 expr ** expr

$\vert$		 expr [*$\vert$/$\vert$«$\vert$»] expr

$\vert$		 expr [+$\vert$-] expr

$\vert$		 expr mod expr

$\vert$		 expr in expr

$\vert$		 expr union expr

$\vert$		 expr [=$\vert$ =$\vert$<$\vert$<=$\vert$>$\vert$>=] expr

$\vert$		 ~ expr

$\vert$		 expr & expr

$\vert$		 expr [|$\vert$^] expr

$\vert$		 expr <-> expr

$\vert$		 expr -> expr

$\vert$		 expr ? expr : expr

$\vert$		 expr .. expr

$\vert$		 ( expr )

$\vert$		 [ expr,$\ldots$,expr ]

$\vert$		 [ expr,$\ldots$,expr : atom = expr .. expr ]

$\vert$		 bin ( expr , expr )

All operators of the same precedence except ``?:'' associate to the left. For example, a / b * c is parsed as (a / b) * c. The ternary ``?:'' associates to the right. Thus

        a ? b : c ? d : e

is parsed as

        a ? b : (c ? d : e)