5 Statements

5.1 Simple and Compound Statements

• Use only one statement or label per line.
• A longer sequence_of_statements may be divided in logical groups or separated from surrounding code using a blank line.

5.2 If Statements

• When the if, elsif or else keywords fit on the same line with the condition and the then keyword, then the statement is formatted as follows:

          if condition then
             ...
          elsif condition then
             ...
          else
             ...
          end if;
  

  When the above layout is not possible, then should be aligned with if, and conditions should preferably be split before an and or or keyword a follows:

          if long_condition_that_has_to_be_split
            and then continued_on_the_next_line
          then
             ...
          end if;
  

  The elsif, else and end if always line up with the if keyword. The preferred location for splitting the line is before and or or. The continuation of a condition is indented with two spaces or as many as needed to make nesting clear. As an exception, if conditions are closely related either of the following is allowed:

       if x = lakdsjfhlkashfdlkflkdsalkhfsalkdhflkjdsahf
            or else
          x = asldkjhalkdsjfhhfd
            or else
          x = asdfadsfadsf
       then
         ...
       end if;
  

       if x = lakdsjfhlkashfdlkflkdsalkhfsalkdhflkjdsahf or else
          x = asldkjhalkdsjfhhfd                         or else
          x = asdfadsfadsf
       then
         ...
       end if;
  

• Conditions should use short-circuit forms (and then, or else), except when the operands are boolean variables or boolean constants.
• Complex conditions in if statements are indented two characters:

        if this_complex_condition
          and then that_other_one
          and then one_last_one
        then
           ...
        end if;
  

  There are some cases where complex conditionals can be laid out in manners that do not follow these rules to preserve better parallelism between branches, e.g.

        if xyz.abc (gef) = 'c'
             or else
           xyz.abc (gef) = 'x'
        then
           ...
        end if;
  

• Every if block is preceded and followed by a blank line, except where it begins or ends a sequence_of_statements.

          A := 5;
  
          if A = 5 then
             null;
          end if;
  
          A := 6;
  

5.3 Case Statements

• Layout is as below. For long case statements, the extra indentation can be saved by aligning the when clauses with the opening case.

         case expression is
            when condition =>
               ...
            when condition =>
               ...
         end case;
  

5.4 Loop Statements

• When possible, have for or while on one line with the condition and the loop keyword.

         for J in S'Range loop
            ...
         end loop;
  

  If the condition is too long, split the condition (see “If statements” above) and align loop with the for or while keyword.

        while long_condition_that_has_to_be_split
          and then continued_on_the_next_line
        loop
           ...
        end loop;
  

  If the loop_statement has an identifier, it is laid out as follows:

        Outer : while not condition loop
           ...
        end Outer;
  

5.5 Block Statements

• The declare (optional), begin and end words are aligned, except when the block_statement is named. There is a blank line before the begin keyword:

        Some_Block : declare
           ...
  
        begin
           ...
        end Some_Block;