Sweep includes a powerful search and replace mechanism called
Term Replace, that allows you to quickly and consistently
transform some terms across a Prolog buffer. Term Replace searches
for terms with the same flexibility and precision of Term Search
(see Term Search), while letting you interactively transform and
replace matching terms in place. You can use Term Replace to refactor
your code in many ways, such as extending a predicate with another
argument, or replacing all calls to a predicate with another one while
transposing some of the arguments. If you’re familiar with Emacs’s
Query Replace commands, you can think of Term Replace as a
Prolog-specific superpowered version of
(see (emacs)Query Replace). To initiate Term Replace, use the
Replace some terms after point matching a given template with a given
sweeprolog-query-replace-term (bound to C-c
C-S) prompts for two Prolog terms, the template term and the
replacement term, and then asks for each term in the buffer that
matches the template if you want to replace it. You can use variables
in the template term to capture sub-terms of the matching term, and
use them in the replacement term. For example, if you want to
transpose the two arguments in a bunch of calls to
=/2, you can
R=L as the template term and
L=R as the
This command uses the same underlying term search as C-c C-s
sweeprolog-term-search) does for finding matches, expect that
sweeprolog-query-replace-term only searches from point to the
end of buffer. If you invoke
with an active region, it limits the operation to matching terms in
sweeprolog-query-replace-term highlights the
current match with the
face, and all other matches with the
sweeprolog-query-replace-term-match face. By default, these
faces inherit from
sweeprolog-term-search-match, respectively. Furthermore,
similarly to C-c C-s, you can invoke
sweeprolog-query-replace-term with a prefix argument to refine
the search with an arbitrary Prolog goal that matching terms must
satisfy, or with two prefix arguments to target only terms in certain
contexts. See Term Search for full details about prefix arguments
and search refinement.
sweeprolog-query-replace-term goes over the matching terms in
turn and asks you what to do with each. The available answers are:
Replace the current match and move to the next one.
Skip the current match without replacing it.
Replace the current match, show the result, and suggest reverting back before moving to the next match.
Quit without replacing the current match.
Replace the current match, and exit right away asking about further matches.
Replace the current match and all remaining matches without asking.
Edit the replacement term for the current match in the minibuffer, and then perform the replacement.
Enter recursive edit. This allows you to pause the current Term Replace session, perform some edits, or otherwise use Emacs however you please, an then resume Term Replace from the same point by typing C-M-c. See (emacs)Recursive Edit.
If you include a new variable in the replacement term
that does not appear in the template term,
sweeprolog-query-replace-term uses that variable as-is in each
replacement, expect if the matching term happens to contain a variable
with that name already, in which case this command adds the suffix
‘Fresh’ to the name of the new variable from the replacement.
Including a new variable in the replacement term is useful, for
example, for introducing a new argument to a predicate.