Expressions

Expressions are formed from variables and constants by using operators and functions and by combining expressions together into arrays (array expressions).

The following diagram summarizes all kinds of expressions:

Operator expressions

The CPO file format supports a variety of operators.

The following table summarizes the supported operators. Operator precedence is mostly inspired by the C programming language.

Precedence	Associativity	Operator	Description	Argument(s)	Result
1	Right-to-left	`-`	Unary minus	`-intExpr`	`intExpr`
				`-floatExpr`	`floatExpr`
				`-cumulExpr`	`cumulExpr`
		`!`	Logical not	`!boolExpr`	`boolExpr`
2	Left-to-right	`^`	Power	`floatExpr ^ floatExpr`	`floatExpr`
3	Left-to-right	`*`	Multiplication	`intExpr * intExpr`	`intExpr`
		`*`	Multiplication	`floatExpr * floatExpr`	`floatExpr`
		`/`	Division	`floatExpr / floatExpr`	`floatExpr`
		`div`	Integral division	`intExpr div intExpr`	`intExpr`
		`%`	Modulo (remainder)	`intExpr % intExpr`	`intExpr`
4	Left-to-right	`+`	Addition	`intExpr + intExpr`	`intExpr`
				`floatExpr + floatExpr`	`floatExpr`
				`cumulExpr + cumulExpr`	`cumulExpr`
		`-`	Subtraction	`intExpr - intExpr`	`intExpr`
				`floatExpr - floatExpr`	`floatExpr`
				`cumulExpr - cumulExpr`	`floatExpr`
5	Left-to-right	`<`	Less	`intExpr < intExpr`	`boolExpr`
		`>`	Greater	`intExpr > intExpr`	`boolExpr`
		`<=`	Less or equal	`intExpr <= intExpr`	`boolExpr`
				`floatExpr <= floatExpr`	`boolExpr`
				`cumulExpr <= uint`	`constraint`
				`uint <= cumulExpr`	`constraint`
				`cumulExpr <= intExpr`	`constraint`
				`intExpr <= cumulExpr`	`constraint`
		`>=`	Greater or equal	`intExpr >= intExpr`	`boolExpr`
				`intExpr >= floatExpr`	`boolExpr`
				`uint >= cumulExpr`	`constraint`
				`cumulExpr >= uint`	`constraint`
				`intExpr >= cumulExpr`	`constraint`
				`cumulExpr >= intExpr`	`constraint`
6	Left-to-right	`==`	Equal to	`intExpr == intExpr`	`boolExpr`
		`==`	Equal to	`floatExpr == floatExpr`	`boolExpr`
		`!=`	Not equal to	`intExpr != intExpr`	`boolExpr`
		`=>`	Logical implies	`boolExpr => boolExpr`	`boolExpr`
7	Left-to-right	`&&`	Logical and	`boolExpr && boolExpr`	`boolExpr`
8	Left-to-right	`\|\|`	Logical or	`boolExpr \|\| boolExpr`	`boolExpr`

Note the difference between == and = operators: The single equals sign = can be used only in statements identifier = expression;, while a double equal sign == is an operator that returns a Boolean expression.

Example


x = intVar(1..10);
y = intVar(1..10);
z = intVar(1..10);
expr1 = 2*(x + y);
expr2 = y % z;
expr1 + 2 >= expr2;

Function expressions

There are many built-in functions that return expressions, see the list of functions. The syntax to call a function follows a common standard:

There are a few exceptional functions that require extended syntax, for example intVar or intervalVar. In this case, the syntax is described together with the function.

Example


x = intVar(-10..10); // intVar is a function with special syntax
absx = abs(x);       // abs is a function returning absolute value of x