Expressions

Expressions occur in assignments or in tests. Expressions produce a value, of a certain type.

Expressions are built with two components: Operators and their operands. Usually an operator is binary, i.e. it requires 2 operands. Binary operators occur always between the operands (as in X/Y). Sometimes an operator is unary, i.e. it requires only one argument. A unary operator occurs always before the operand, as in -X.

When using multiple operands in an expression, the precedence rules of table () are used.

When determining the precedence, te compiler uses the following rules:

1. Operations with equal precedence are executed from left to right.
2. In operations with unequal precedence the operands belong to the operater with the highest precedence. For example, in 5*3+7, the multiplication is higher in precedence than the addition, so it is executed first. The result would be 22.
3. If parentheses are used in an epression, their contents is evaluated first. Thus, 5*(3+7) would result in 50.

An expression is a sequence of terms and factors. A factor is an operand of a multiplication operator. A term is an operand of an adding operator.

 
• Expression syntax
• Function calls
• Set constructors
• Value typecasts
• The @ operator
• Operators