| Type: | Package |
| Title: | Embed 'SWI'-'Prolog' |
| Version: | 9.3.21 |
| Date: | 2025-03-20 |
| Maintainer: | Matthias Gondan <Matthias.Gondan-Rochon@uibk.ac.at> |
| Description: | Interface to 'SWI'-'Prolog', https://www.swi-prolog.org/. This package is normally not loaded directly, please refer to package 'rolog' instead. The purpose of this package is to provide the 'Prolog' runtime on systems that do not have a software installation of 'SWI'-'Prolog'. |
| License: | FreeBSD |
| Imports: | Rcpp (≥ 1.0.7) |
| Depends: | R (≥ 4.2) |
| URL: | https://github.com/mgondan/rswipl |
| BugReports: | https://github.com/mgondan/rswipl/issues |
| LinkingTo: | Rcpp |
| RoxygenNote: | 7.3.2 |
| Encoding: | UTF-8 |
| SystemRequirements: | GNU make, CMake (>= 3.10), pandoc, libarchive, libregex, libexpat, liblzma, libzstd, liblz4, libz2, libz, libbcrypt |
| Suggests: | testthat (≥ 3.0.0) |
| Config/testthat/edition: | 3 |
| NeedsCompilation: | yes |
| Packaged: | 2025-03-21 20:56:07 UTC; matthias |
| Author: | Matthias Gondan [aut, com, cre] (University of Innsbruck), Jan Wielemaker [ctb, cph] (JW is the lead developer of SWI-Prolog. See https://www.swi-prolog.org/Contributors.html for a list of contributors.), European Commission [fnd] (Erasmus+ Programme, 2019-1-EE01-KA203-051708) |
| Repository: | CRAN |
| Date/Publication: | 2025-03-21 22:30:02 UTC |
Clear current query
Description
Clear current query
Usage
clear()
Value
TRUE (invisible)
See Also
query()
for opening a query
submit()
for submitting a query
Examples
query(call("member", expression(X), list(quote(a), "b", 3L, 4)))
submit() # X = a
submit() # X = "b"
clear()
Create a query
Description
Create a query
Usage
query(
q = call("member", expression(X), list(quote(a), "b", 3L, 4, TRUE, expression(Y)))
)
Arguments
q |
an R call. The R call consists of symbols, integers and real numbers, character strings, boolean values, expressions, lists, and other calls. Vectors of booleans, integers, floating point numbers, and strings with length N > 1 are translated to prolog compounds !/N, %/N, #/N and $$/N, respectively. |
Details
SWI-Prolog does not allow multiple open queries. If another query is open, it it is closed and a warning is shown.
Value
If the creation of the query succeeds, TRUE
See Also
submit()
for submitting a query
clear()
to close the currently open query
Examples
query(call("writeln", function(x) {sin(x)}))
submit()
clear()
query(call("=", expression(X), function(x) {sin(x)}))
submit()
clear()
query(call("member", expression(X), list(quote(a), "b", 3L, 4, TRUE, expression(Y),
NA, NaN, Inf, NULL, NULL, function(x) {y <- sin(x); y^2}, NULL)))
submit() # X = a
submit() # X = "b"
submit() # X = 3L
submit() # X = 4.0
submit() # X = TRUE
submit() # X = expression(Y) or Y = expression(X)
submit() # X = NA
submit() # X = NaN
submit() # X = Inf
submit() # X = NULL
submit() # X = NULL
submit() # X = function(x) {y <- sin(x); y^2}))
submit() # X = NULL
submit() # FALSE (no more results)
submit() # warning that no query is open
query(call("member", expression(X), list(quote(a), "b", 3L, 4)))
query(call("member", expression(X), list(TRUE, expression(Y)))) # warning that another query is open
clear()
Submit a query that has been opened with query() before.
Description
Submit a query that has been opened with query() before.
Usage
submit()
Value
If the query fails, FALSE is returned. If the query succeeds, a
(possibly empty) list is returned that includes the bindings required to
satisfy the query.
See Also
query()
for a opening a query.
clear()
for a clearing a query.
Examples
query(call("member", expression(X), list(quote(a), "b", 3L, 4, expression(Y))))
submit() # X = 3L
submit() # X = 4.0
submit() # X = TRUE
submit() # X = expression(Y) or Y = expression(X)
submit() # FALSE
submit() # warning that no query is open
query(call("member", expression(X), list(quote(a), "b", 3L, 4)))
submit() # X = a
submit() # X = "b"
clear()
Invoke SWI-Prolog
Description
This function is internally used to emulate swipl -g goal using the R program: R -e "rswipl::swipl()" -q –no-echo –args -g goal
Usage
swipl(sigalert = NA)
Arguments
sigalert |
Use a different alert signal than SIGUSR2 (ignored on Windows) |
Value
nothing useful