"Dedent"

Dedent is a library for improving readability of multi-line string constants in code:

• you can put string delimiters on their own lines
• you can indent lines to the level of surrounding code
• you can start each line with a line prefix, >

More precisely, on an input string, Dedent does the following:

1. breaks the string into lines
2. strips trailing whitespace from all lines
3. drops the first line and the last line, if they are empty
4. finds the line with the least indendation, and drops that indentation from all lines
5. drops the line prefix from all lines, if it is present on all lines

For example:

let string =
  {|
  > a
  >  b
  >   c
  |} |> Dedent.string

That yields the string "a\n b\n c".

Use Dedent.lines to dedent and return a list of lines rather than a string. For the above example, Dedent.lines yields:

[ "a"; " b"; "  c" ]

Each of the aspects of Dedent's input handling is optional. You don't have to use a line prefix. This yields the same string:

let string =
  {|
  a
   b
    c
  |} |> Dedent.string

You don't have to indent. This yields the same string:

let string =
  {|
a
 b
  c
|} |> Dedent.string

You don't have to put delimiters on their own lines. This yields the same string:

let string =
  {|a
 b
  c|} |> Dedent.string

There is also an extension syntax, [%string_dedent], that is a variant of [%string] that applies [Dedent.string] to its input before substitution. For example:

  let bar = "BAR" in
  let string =
    [%string_dedent
      {|
      > foo
      >   %{bar}
      |}]
  in

That yields the string "foo\n BAR".