Tyl Programming Language
▶ VARIABLE ASSIGNMENT
Declare the num_a variable:
num_a
Assign the value: 21 to num_a:
num_a 21
Consider this piece of code:
num_a
print num_a
num_a 21
print num_a
num_a
print num_a
NULL
21
NULL
After the first num_a declaration, num_a has no value, therefore its value is: NULL. In programming languages, the word: 'null' denotes: 'No Value'.
After the assignment line, the value of num_a is: 21.
The second line: num_a, will behave according to its position in the code block. If it is not the last statement it will cause the value of num_a to be: NULL. If it is the last statement it will return num_a value.

Declaration and assignment can be done in one line.
Declare and assign num_b:
num_b 22
Variables can be assigned the value of another variable:
print 'Declare and assign num_a and num_b variables'
num_a 21
num_b 22
print num_a
print num_b
print 'Assign the value of num_a to num_b'
num_b num_a
print num_a
print num_b
Declare and assign num_a and num_b variables
21
22
Assign the value of num_a to num_b
21
21
In line: 'num_b num_a', the value of num_a is copied (or assigned) to num_b. Note that though the variables have the same value, they are independent variables. Let's define the assignment by using the arrow symbol: ''.
Then the assignment: 'num_b num_a', will be denoted:
num_a → num_b


PART 2