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Variables

Learn about the simplest way to store values in ABJAD.

What are Variables?​

Variables are references to values (data) stored in the memory. From the name, we can infer that the value of a variable can change with time.

Declaring a Variable​

Declaration is creating a new variable, giving it a name, a type, and a value.

The syntax for declaring a new variable is as the following:

  1. The keyword متغير (which means variable)

  2. The type of the variable

    Variable Type

    It can either be a primitive type, such as (number: رقم, string: مقطع, boolean: منطق) or a custom defined one (learn more)

  3. The name of the variable

  4. The assignment symbol =

  5. The value of the variable (optional)

    Variable Value

    It can either be a primitive value, such as (12, "مرحبا بالعالم") or an expression, such as (3 + (2 - 4))

  6. A semicolon ؛ for ending the statement

An example of declaring a number variable of name س and value 1:

متغير رقم س = 1؛

Declaring a variable without a value​

Declaring a new variable does not require specifying its value, that's why when there is no value yet to give, you can simply just specify the name and the type of the variable, e.g.:

متغير رقم س؛
Undefined Variable

When omitting the value from the variable declaration, an undefined value will be temporarily assigned to the reference. This value makes the reference unuseful until given a real value.

i.e.

The following example is erroneous:

متغير رقم س؛
متغير رقم ش = س؛

While the following is fine:

متغير رقم س؛
س = 1؛
متغير رقم ش = س؛

Using a Variable​

Once a variable was declared with a value, it can be used in the code like any other literal.

An example of printing the value of a variable:

متغير مقطع رسالة = "مرحبا بالعالم"؛
أكتب(رسالة)؛

Changing a Variable's Value​

Changing the value of a variable, or assigning it a new one, is very similar, in syntax, to declaring one, just without the متغير keyword and the type, that are limited to declaration only.

متغير مقطع كلمة = "مرحبا"؛
كلمة = "أهلا"؛
info

Changing the value of a number or bool variable is not allowed.