ediprolog lets you interact with SWI-Prolog in all Emacs buffers.
You can consult Prolog programs and evaluate embedded queries.

Installation
============

Copy ediprolog.el to your load-path and add to your .emacs:

    (require 'ediprolog)
    (global-set-key [f10] 'ediprolog-dwim)

Restart Emacs and customize ediprolog with

    M-x customize-group RET ediprolog RET


Usage
=====

The central function is `ediprolog-dwim' (Do What I Mean), which is
bound to F10 by the snippet above. Depending on the content at
point, `ediprolog-dwim' does the "appropriate" thing: If point is
on a query, F10 sends the query to a Prolog process, and you
interact with the process in the current buffer as on a terminal.
Queries start with "?-" or ":-", possibly preceded by "%" and
whitespace. An example of a query is:

  %?- member(X, [a,b,c]).

If you press F10 when point is on that query, you get:

  %?- member(X, [a,b,c]).
  %@ X = a ;
  %@ X = b ;
  %@ X = c ;
  %@ false.

When waiting for output of the Prolog process, you can press C-g to
unblock Emacs and continue with other work. To resume interaction
with the Prolog process, use M-x ediprolog-toplevel RET.

If you press F10 when point is NOT on a query, the buffer content
is consulted in the Prolog process, and point is moved to the first
error (if any).

For convenience, the most recent interactions with the Prolog
process are logged in the buffer "*ediprolog-history*".

Use M-x ediprolog-localize RET to make any Prolog process started
in the current buffer buffer-local. This way, you can run distinct
processes simultaneously. Revert with M-x ediprolog-unlocalize RET.

`ediprolog-dwim' with prefix arguments has special meanings:

  C-0 F10       kill Prolog process
  C-1 F10       always consult buffer (even when point is on a query)
  C-2 F10       always consult buffer, using a new process
  C-7 F10       equivalent to `ediprolog-toplevel'
  C-u F10       first consult buffer, then evaluate query (if any)
  C-u C-u F10   like C-u F10, with a new process

Tested with SWI-Prolog 5.6 and 6.6 + Emacs 21.2, 22.3, 23.1 and 24.3