Tyl Programming Language
Variables are used to store data, while the program is running.
Regular variables as: strings, numbers, real numbers and booleans, are called scalar variables.

Here are some scalar variables declarations:
name 'Tony'
age 22
height 176.80
Tyl variables features:
Tyl has also list variables, that can store a list of items.
Consider these list variables declarations:
names 'Tony' 'Carla' 'Ron'
ages 22 28 17
Tyl list variables features:
Tyl identifies a token as a list variable, by checking if the token ends with the letter: 's'. It is a good practice to name lists with plural suffix and scalars without plural suffix.
While it is common to declare a variable and assign a value to it in the same line, Tyl permits variable declaration without value assignment.

In this code:
prices variable will be defined as a list without items, and sum_total variable will have undefined type, which is considered 'NULL'.

Attention: The letter: 's' is not valid for variable name!

Wrong variable declaration with 's':
s 100
The variable: 's', is invalid by Tyl conventions, will not be declared nor assigned, and nothing will happen!

For more Information about variables: