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module Easy_format

: sig

Easy_format: indentation made easy.

This module provides a functional, simplified layer over the Format module of the standard library.

Input data must be first modelled as a tree using 3 kinds of nodes:

  • atoms
  • lists
  • labelled nodes

Atoms represent any text that is guaranteed to be printed as-is. Lists can model any sequence of items such as arrays of data or lists of definitions that are labelled with something like "int main", "let x =" or "x:".

#
type wrap = [
| `Wrap_atoms
| `Always_wrap
| `Never_wrap
| `Force_breaks
| `No_breaks
]

List wrapping conditions:

  • `Wrap_atoms: wrap if the list contains only atoms
  • `Always_wrap: always wrap when needed
  • `Never_wrap: never wrap, i.e. the list is either horizontal or vertical
  • `Force_breaks: align vertically, i.e. always break line between list items and align the left edge of each item.
  • `No_breaks: align horizontally, i.e. never break line between list items
#
type style_name = string
#
type style = {
# tag_open
: string;
# tag_close
: string;
}

Pair of opening and closing tags that are inserted around text after pretty-printing.

#
type atom_param = {
# atom_style
: style_name option;(*Default: None*)
}
#
val atom : atom_param
#
type list_param = {
# space_after_opening
: bool;(*Whether there must be some whitespace after the opening string. Default: true*)
# space_after_separator
: bool;(*Whether there must be some whitespace after the item separators. Default: true*)
# space_before_separator
: bool;(*Whether there must be some whitespace before the item separators. Default: false*)
# separators_stick_left
: bool;(*Whether the separators must stick to the item on the left. Default: true*)
# space_before_closing
: bool;(*Whether there must be some whitespace before the closing string. Default: true*)
# stick_to_label
: bool;(*Whether the opening string should be fused with the preceding label. Default: true*)
# align_closing
: bool;(*Whether the beginning of the closing string must be aligned with the beginning of the opening string (stick_to_label = false) or with the beginning of the label if any (stick_to_label = true). Default: true*)
# wrap_body
: wrap;(*Defines under which conditions the list body may be wrapped, i.e. allow several lines and several list items per line. Default: `Wrap_atom_list*)
# indent_body
: int;(*Extra indentation of the list body. Default: 2*)
# list_style
: style_name option;(*Default: None*)
# opening_style
: style_name option;(*Default: None*)
# body_style
: style_name option;(*Default: None*)
# separator_style
: style_name option;(*Default: None*)
# closing_style
: style_name option;(*Default: None*)
}

List-formatting parameters. Always derive a new set of parameters from an existing record. See Easy_format.list.

#
val list : list_param

Default list-formatting parameters, using the default values described in the type definition above.

In order to make code compatible with future versions of the library, the record inheritance syntax should be used, e.g. { list with align_closing = false }. If new record fields are added, the program would still compile and work as before.

#
type label_param = {
# space_after_label
: bool;(*Whether there must be some whitespace after the label. Default: true*)
# indent_after_label
: int;(*Extra indentation before the item that comes after a label. Default: 2*)
# label_style
: style_name option;(*Default: None*)
}

Label-formatting parameters. Always derive a new set of parameters from an existing record. See Easy_format.label.

#
val label : label_param

Default label-formatting parameters, using the default values described in the type definition above.

In order to make code compatible with future versions of the library, the record inheritance syntax should be used, e.g. { label with indent_after_label = 0 }. If new record fields are added, the program would still compile and work as before.

#
type t =
# | Atom of string * atom_param
(*Plain string normally without line breaks.*)
# | List of (string * string * string * list_param) * t list
(*List ((opening, separator, closing, param), nodes)*)
# | Label of (t * label_param) * t
(*Label ((label, param), node): labelled node.*)
# | Custom of Format.formatter -> unit
(*User-defined printing function that allows to use the Format module directly if necessary. It is responsible for leaving the formatter in a clean state.*)

The type of the tree to be pretty-printed. Each node contains its own formatting parameters.

Detail of a list node List ((opening, separator, closing, param), nodes):

  • opening: opening string such as "{" "[" "(" "begin" "" etc.
  • separator: node separator such as ";" "," "" "+" "|" etc.
  • closing: closing string such as "}" "]" ")" "end" "" etc.
  • nodes: elements of the list.
#
type escape = [
| `None
| `Escape of (string -> int -> int -> unit) -> string -> int -> int -> unit
| `Escape_string of string -> string
]
#
type styles = (style_name * style) list
#
module Pretty : sig

The regular pretty-printing functions

#
val define_styles : Format.formatter -> escape -> styles -> unit
#
val to_formatter : Format.formatter -> t -> unit
#
val to_buffer : ?escape:escape -> ?styles:styles -> Buffer.t -> t -> unit
#
val to_string : ?escape:escape -> ?styles:styles -> t -> string
#
val to_channel : ?escape:escape -> ?styles:styles -> Pervasives.out_channel -> t -> unit
#
val to_stdout : ?escape:escape -> ?styles:styles -> t -> unit
#
val to_stderr : ?escape:escape -> ?styles:styles -> t -> unit
end
#
module Compact : sig

No spacing or newlines other than those in the input data or those produced by Custom printing.

#
val to_buffer : Buffer.t -> t -> unit
#
val to_string : t -> string
#
val to_channel : Pervasives.out_channel -> t -> unit
#
val to_stdout : t -> unit
#
val to_stderr : t -> unit
#
val to_formatter : Format.formatter -> t -> unit
end
end