Assignment

rascal-0.40.17

Synopsis

Assign a value to a variable or more complex data structure.

Syntax

Assignable AssignmentOp Exp

where AssignmentOp may be one of =, +=, -=, *=, /=, or ?=.

An Assignable is one of the following:

• Var
• Assignable [ Exp ]
• Assignable [ Exp .. Exp ]
• Assignable [ Exp, Exp .. Exp ]
• Assignable . Name
• < Assignable, Assignable, ..., Assignable >
• Assignable ? Exp
• Assignable @ Name
• Name ( Assignable, Assignable, ... )

Description

The purpose of an assignment is to assign a new value to a simple variable or to an element of a more complex data structure.

The standard assignment operator is =. The other assignment operators can be expressed as abbreviations for the standard assignment operator.

Assignment Operator	Equivalent to
Assignable += Exp	Assignable = Assignable + Exp
Assignable -= Exp	Assignable = Assignable - Exp
Assignable *= Exp	Assignable = Assignable * Exp
Assignable /= Exp	Assignable = Assignable / Exp
Assignable &= Exp	Assignable = Assignable & Exp
Assignable ?= Exp	Assignable = Assignable ? Exp

An assignable is either a single variable, (the base variable), optionally followed by subscriptions, slices or field selections. The assignment statement always results in assigning a completely new value to the base variable. We distinguish the following forms of assignment:

• Annotation
• Constructor
• Field
• IsDefined
• Multiple
• Slice
• Subscription
• Variable