if Instruction

The if instruction executes Jade instructions dependent upon a condition.

Syntax

The forms of the Jade conditional instruction are:

• if boolean-expression then
      [instructions]
  endif;

  This executes the instructions if the condition evaluates to true.

• if boolean-expression then
      [instructions]
  else
      [instructions]
  endif;

  This executes the first sequence of instructions if the condition evaluates to true and the second sequence if the condition evaluates to false.

• if boolean-expression then
      [instructions]
  elseif boolean-expression then
      [instructions]
  elseif boolean-expression then
      [instructions]
  else
      [instructions]
  endif;

  The elseif clause is equivalent to an else clause followed by a further nested if instruction. The else part remains optional when there is one or more elseif clause.

Description

Use the if instruction to perform conditional execution, based on the evaluation of an expression.

Examples

The following example shows a series of nested if instructions.

getJobTitle(level: Integer): String;
begin
    if level = 1 then
        return "CEO";
    else
        if level = 2 then
            return "Project Manager";
        else
            if level = 3 then
                return "Analyst";
            else
                if level = 4 then
                    return "Programmer";
                else
                    return "Invalid level";
                endif;
            endif;
        endif;
    endif;
end;

This can be written in a more compact and readable way, by making use of the elseif clause, as shown in the following example.

getJobTitle(level: Integer): String;
begin
    if level = 1 then
        return "CEO";
    elseif level = 2 then
        return "Project Manager";
    elseif level = 3 then
        return "Analyst";
    elseif level = 4 then
        return "Programmer";
    else
        return "Invalid level";
    endif;
end;