5.8. Code style

This chapter is a style guide of multiple-line structures. For expressions which fit in a single line, you can choose any style.

5.8.1. Indentation

Indentation is done with 2 whitespaces for each level.

The indentation level of is calculated by the following rule: The indentation level is the number of pairs of parentheses, braces, and brackets which enclose the first token of the line.

See the example below.

:foo <- {(:X :Y)  # (a)
  bar(  # (b)
    42
    []
    { xxx
      yyy
      zzz
    } # (c)
  )
}

The first token of the line (a), :, is not enclosed by any parentheses, braces, or brackets. So the indentation level is 0.

The first token of the line (b), bar, is enclosed by the pair of parentheses opened at (a). So the indentation level is 1.

The line (c) consists of only a closing brace. It is enclosed by a pair of brace opened at (a), and a pair of parentheses opened at (b). So the indentation level is 2.

5.8.2. Parentheses, braces and brackets

If a pair of parentheses, braces, or brackets spans multiple lines,

• the opening parenthesis, brace, or bracket should not be the only token of a line, and

• the closing parenthesis, brace, or bracket should remain on its own line.

See the example again.

:foo <- {(:X :Y)  # (d)
  bar(  # (e)
    42
    []
    { xxx # (f)
      yyy
      zzz
    } # (g)
  ) # (h)
} # (i)

The opening brace of (d) and the opening parenthesis (e) follow other tokens, so it follows the rule.

The opening brace of (f) is the first token of the line. In order not make it the only token of the line, the first expression xxx follows the opening brace.

The closing braces of (g), (i) and the closing parenthesis (h) close multiple-line parentheses and braces. Thus, they remain on their own lines.