Conditional Flow

What would a program be without any decisions? Really boring. There are two kinds of conditional statements available in Back, if and switch. But what is a condition and conditional control flow? Let's figure it out.

Conditions

A condition always evaluates to true or false. Conditions can be combined with relational operators. Here is a list:

operator	description
! not	The logical not operator inverts the result. true => false and false => true
&& and	The logical and combines two conditions. It evaluates to true only if both conditions are true
|| or	The logical or operator evaluates to true if one of the operands are true

If-Statements

If-statements allow you to brnch the flow of control.

Here is the syntactic structure of a full if-statement:

<if_statement> ::= "if" <condition> "{" <trueBody> "}" ("else" "{" <falseBody> "}")?

If only one statement is given for the body the curly braces can be left out.

Here is a simple example:

func main() {
    let isHappy = true;

    if isHappy {
        print("You are happy.");
    }
    else {
        print("You are not happy");
    }
}