Module Pretty

The type of unformated documents. Elements of this type can be constructed in two ways. Either with a number of constructor shown below, or using the Pretty.dprintf function with a printf-like interface. The Pretty.dprintf method is slightly slower so we do not use it for large jobs such as the output routines for a compiler. But we use it for small jobs such as logging and error messages.

Constructs an empty document

Concatenates two documents. This is an infix operator that associates to the left.

A document that prints the given string

A document that prints an integer in decimal form

A document that prints a 64-bit int in decimal form

A document that prints a real number

A document that prints a character. This is just like Pretty.text with a one-character string.

A document that consists of a mandatory newline. This is just like (text "\n"). The new line will be indented to the current indentation level, unless you use Pretty.leftflush right after this.

Use after a Pretty.line to prevent the indentation. Whatever follows next will be flushed left. Indentation resumes on the next line.

A document that consists of either a space or a line break. Also called an optional line break. Such a break will be taken only if necessary to fit the document in a given width. If the break is not taken a space is printed instead.

Mark the current column as the current indentation level. Does not print anything. All taken line breaks will align to this column. The previous alignment level is saved on a stack.

Reverts to the last saved indentation level.

Mark the beginning of a markup section. The width of a markup section is considered 0 for the purpose of computing identation

The end of a markup section

Indents the document. Same as ((text " ") ++ align ++ doc ++ unalign), with the specified number of spaces.

Prints a document as markup. The marked document cannot contain line breaks or alignment constructs.

Formats a sequence. sep is a separator, doit is a function that converts an element to a document.

An alternative function for printing a list. The unit argument is there to make this function more easily usable with the Pretty.dprintf interface. The first argument is a separator, by default a comma.

sm: Yet another list printer. This one accepts the same kind of printing function that Pretty.dprintf does, and itself works in the dprintf context. Also accepts a string as the separator since that's by far the most common.

Formats an array. A separator and a function that prints an array element. The default separator is a comma.

Prints an 'a option with None or Some

Print an int32

A function that is useful with the printf-like interface

This function provides an alternative method for constructing doc objects. The first argument for this function is a format string argument (of type ('a, unit, doc) format; if you insist on understanding what that means see the module Printf). The format string is like that for the printf function in C, except that it understands a few more formatting controls, all starting with the @ character.

See the gprintf function if you want to pipe the result of dprintf into some other functions.

The following special formatting characters are understood (these do not correspond to arguments of the function):

• @[ Inserts an Pretty.align. Every format string must have matching Pretty.align and Pretty.unalign.
• @] Inserts an Pretty.unalign.
• @! Inserts a Pretty.line. Just like "\n"
• @? Inserts a Pretty.break.
• @< Inserts a Pretty.mark.
• @> Inserts a Pretty.unmark.
• @^ Inserts a Pretty.leftflush Should be used immediately after @! or "\n".
• @@ : inserts a @ character

In addition to the usual printf % formatting characters the following two new characters are supported:

• %t Corresponds to an argument of type unit -> doc. This argument is invoked to produce a document
• %a Corresponds to two arguments. The first of type unit -> 'a -> doc and the second of type 'a. (The extra unit is do to the peculiarities of the built-in support for format strings in Ocaml. It turns out that it is not a major problem.) Here is an example of how you use this:

dprintf "Name=%s, SSN=%7d, Children=@[%a@]\n"
             pers.name pers.ssn (docList (chr ',' ++ break) text)
             pers.children

The result of dprintf is a Pretty.doc. You can format the document and emit it using the functions Pretty.fprint and Pretty.sprint.

Like Pretty.dprintf but more general. It also takes a function that is invoked on the constructed document but before any formatting is done. The type of the format argument means that 'a is the type of the parameters of this function, unit is the type of the first argument to %a and %t formats, doc is the type of the intermediate result, and 'b is the type of the result of gprintf.

Format the document to the given width and emit it to the given channel

Format the document to the given width and emit it as a string

Like Pretty.dprintf followed by Pretty.fprint

Like Pretty.fprintf applied to stdout

Like Pretty.fprintf applied to stderr

Invokes a thunk, with printDepth temporarily set to the specified value

Specifies the nesting depth of the align/unalign pairs at which everything is replaced with ellipsis

If false then does not indent

If set to true then optional breaks are taken only when the document has exceeded the given width. This means that the printout will looked more ragged but it will be faster

If true the it flushes after every print

Whether to rebalance doc before printing it to avoid stack-overflows

Keep a running count of the taken newlines. You can read and write this from the client code if you want

A function that when used at top-level in a module will direct the pa_prtype module generate automatically the printing functions for a type