Part 4.2If statements

One of the most useful programming constructs in any programming language is flow control. The if statement is the simplest flow control construct.

Building an if statement

In YASS, an if statement follows a structure similar to VB.NET. There are only two essentials of an if statement, that is, the if at the start and the end if at the end.

The following code sample demonstrates the structure of an if statement in YASS:

if (x ? y)
  //Do something here
end if

Where x and y represent some variables and ? represents a conditional operator. For example:

if (10 > 5)
  print("Yes")
  $v = true
end if

If statement in YASS can also be shortened using the then keyword:

if x ? y then
  //Do something here

For example:

if 10 > 5 then
  print("Yes")

Whilst from time to time it maybe handy to use the shorthand syntax, it is often the case that the full syntax is easier to read.

Else

If a condition is not satisified it evaluates to false. When this happens an if statement will ignore the code on the inside of the statement and will not execute it. This is where else statements come in.

If the condition evaluates to false and an else statement is provided then the program will execute the code within the else statement. 

if (10 > 5)
  print("Yes")
  $v = true
else
  print("No")
  $v = false
end if

Note that else statement can also be used with the shorthand syntax if statement.

if 10 > 5 then
  print("Yes")
else
  print("No")

The usual rule of one expression after the then keyword applies to the code after the else keyword.