[Next] [Up] [Previous] [Contents]

Expressions

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

 
		 expr::					id

						|		 number

						|		 { atom,  ,atom }

						|		 expr :: expr

						|		 [-|+|*|&|||^] expr

						|		 expr ** expr

						|		 expr [*|/|<<|>>] expr

						|		 expr [+|-] expr

						|		 expr mod expr

						|		 expr in expr

						|		 expr union expr

						|		 expr [=| =|<|<=|>|>=] expr

						|		 ~ expr

						|		 expr & expr

						|		 expr [||^] expr

						|		 expr <-> expr

						|		 expr -> expr

						|		 expr ? expr : expr

						|		 expr .. expr

						|		 ( expr )

						|		 [ expr,  ,expr ]

				            |		 [ expr,  ,expr : atom = expr .. expr ]

				            |		 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)