SWI-Prolog offers an extensible interface which allows the user to edit objects of the program: predicates, modules, files, etc. The editor interface is implemented by edit/1 and consists of three parts: locating, selecting and starting the editor. Any of these parts may be customized. See section 4.4.1.
The built-in edit specifications for edit/1 (see prolog_edit:locate/3) are described in the table below:
|Fully specified objects|
|<Module>:<Name>/<Arity>||Refers to a predicate|
|module(<Module>)||Refers to a module|
|file(<Path>)||Refers to a file|
|source_file(<Path>)||Refers to a loaded source file|
|<Name>/<Arity>||Refers to this predicate in any module|
|<Name>||Refers to (1) the named predicate in any module with any arity, (2) a (source) file, or (3) a module.|
The predicates described in this section are hooks that can be defined to disambiguate specifications given to edit/1, find the related source, and open an editor at the given source location.
Location is a list of attributes of the location.
Normally, this list will contain the term
if available, the term
If it fails, edit/1
uses its internal defaults, which are defined by the Prolog flag editor
and/or the environment variable
EDITOR. The following rules apply. If the Prolog flag editor
is of the format
$<name>, the editor is
determined by the environment variable <name>. Else, if
this flag is
and XPCE is loaded or can be loaded, the built-in Emacs clone
is used. Else, if the environment
EDITOR is set, this
editor is used. Finally,
vi is used as default on Unix systems and notepad on
See the default user preferences file
.exe) extension. Command is an atom describing the command. The following %-sequences are replaced in Command before the result is handed to shell/1:
|%e||Replaced by the (OS) command name of the editor|
|%f||Replaced by the (OS) full path name of the file|
|%d||Replaced by the line number|
If the editor can deal with starting at a specified line, two clauses should be provided. The first pattern invokes the editor with a line number, while the second is used if the line number is unknown.
The default contains definitions for vi, emacs, emacsclient, vim, notepad^* and wordpad^*. Starred editors do not provide starting at a given line number.
Please contribute your specifications to email@example.com.
library(swi_edit), containing definitions to locate classes and methods as well as to bind this package to the PceEmacs built-in editor.
:- multifile prolog_edit:load/0. prolog_edit:load :- ensure_loaded(library(swi_edit)).