diff options
| -rw-r--r-- | .editorconfig | 8 | ||||
| -rw-r--r-- | .gitignore | 2 | ||||
| -rw-r--r-- | LICENSE | 20 | ||||
| -rw-r--r-- | Makefile | 20 | ||||
| -rw-r--r-- | README | 42 | ||||
| -rw-r--r-- | uswipl.c | 68 |
6 files changed, 160 insertions, 0 deletions
diff --git a/.editorconfig b/.editorconfig new file mode 100644 index 0000000..316e750 --- /dev/null +++ b/.editorconfig @@ -0,0 +1,8 @@ +root = true + +[*] +end_of_line = lf +insert_final_newline = true +indent_style=tab +charset = utf-8 +trim_trailing_whitespace = true diff --git a/.gitignore b/.gitignore new file mode 100644 index 0000000..6fb0fe3 --- /dev/null +++ b/.gitignore @@ -0,0 +1,2 @@ +uswipl +*.o @@ -0,0 +1,20 @@ +MIT License + +Copyright (c) 2025 B. Bergeron <[email protected]> + +Permission is hereby granted, free of charge, to any person obtaining a copy of +this software and associated documentation files (the "Software"), to deal in +the Software without restriction, including without limitation the rights to +use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of +the Software, and to permit persons to whom the Software is furnished to do so, +subject to the following conditions: + +The above copyright notice and this permission notice shall be included in all +copies or substantial portions of the Software. + +THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR +IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS +FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR +COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER +IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN +CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. diff --git a/Makefile b/Makefile new file mode 100644 index 0000000..88e5ace --- /dev/null +++ b/Makefile @@ -0,0 +1,20 @@ +# uswipl - dumbed-Down SWI-Prolog REPL +# See LICENSE file for copyright and license details. + +.POSIX: + +CFLAGS = -std=c99 -Wall -Wextra $(shell pkg-config --cflags swipl) -D_POSIX_C_SOURCE=200809L +LDFLAGS = $(shell pkg-config --libs swipl) -Wl,-rpath,$(shell pkg-config --variable=libdir swipl) + +TARGET = uswipl +SRC = uswipl.c + +all: $(TARGET) + +$(TARGET): $(SRC) + $(CC) $(CFLAGS) -o $(TARGET) $(SRC) $(LDFLAGS) + +clean: + rm -f $(TARGET) + +.PHONY: all clean @@ -0,0 +1,42 @@ +uswipl - dumbed-Down SWI-Prolog REPL +==================================== +uswipl is a dumbed-down, IPC-friendly Prolog REPL built on top of SWI-Prolog. + +Requirements +------------ +To build uswipl, you need SWI-Prolog installed. + +Installation +------------ +Enter the following command to build uswipl: + + make uswipl + +Running uswipl +-------------- +uswipl takes the same arguments as `swipl(1)`, it's REPL only allows two types +of interactions: + +1. Assertions, which are done by entering an exclamation mark followed by a + term, e.g.: + + !a :- b + +2. Queries on unary predicates, which are done by entering a question mark + followed by a predicate name. uswipl will then proceed to print each result + for that predicate, one per line. e.g.: + + ?mypred + +uswipl will terminate on error, misinput, upon receiving a signal, or when +reading EOF from stdin. + +Ok, but why? +------------ +Because (SWI/GNU) Prolog is awesome but a pain to call from other languages. The C API is +what it is, and the REPL doesn't seem to have been built with IPC in mind. + +You can start uswipl from any other programming language, provide an init `-f` +or a state `-x` file containing your main Prolog logic, and, through a few +queries and assertions, be done with gluing your software together. + diff --git a/uswipl.c b/uswipl.c new file mode 100644 index 0000000..1c92515 --- /dev/null +++ b/uswipl.c @@ -0,0 +1,68 @@ +#include <errno.h> +#include <stdio.h> +#include <stdlib.h> +#include <sys/types.h> +#include <SWI-Prolog.h> + +int main(int argc, char **argv) +{ + char *input; + size_t input_size; + ssize_t input_len; + char *output; + term_t term; + predicate_t pred; + qid_t query; + + if (!PL_initialise(argc, argv)) + return EXIT_FAILURE; + + input = NULL; + while (errno = 0, (input_len = getline(&input, &input_size, stdin)) != -1) { + switch (input[0]) { + case '!': + if ((term = PL_new_term_ref()) == (term_t)0) + return EXIT_FAILURE; + + if (PL_put_term_from_chars(term, REP_UTF8 | CVT_EXCEPTION, -1, &input[1]) == FALSE) + return EXIT_FAILURE; + + if (PL_assert(term, NULL, PL_ASSERTZ) == FALSE) + return EXIT_FAILURE; + + break; + + case '?': + input[input_len - 1] = '\0'; + if ((pred = PL_predicate(&input[1], 1, NULL)) == (predicate_t)0) + return EXIT_FAILURE; + + if ((term = PL_new_term_ref()) == (term_t)0) + return EXIT_FAILURE; + + query = PL_open_query(NULL, PL_Q_NODEBUG, pred, term); + while (PL_next_solution(query) == TRUE) { + if (PL_get_chars(term, &output, CVT_ALL | CVT_VARIABLE | CVT_EXCEPTION | BUF_MALLOC | REP_UTF8) == FALSE) + return EXIT_FAILURE; + puts(output); + PL_free(output); + } + PL_close_query(query); + + break; + + default: + fputs("Unexpected input\n", stderr); + return EXIT_FAILURE; + } + } + + free(input); + + if (errno) { + perror("Failed to read line from standard input"); + return EXIT_FAILURE; + } + + return EXIT_SUCCESS; +} |