Add options to PrologMain to emulate usage in Gerrit
Disable features by default like IO and STATISTICS but
allow them to be enabled with flags on the command line.
Allow the caller to parse files outside of Prolog similar
to Gerrit by passing in `-f foo.pl` flags to consult from
a stream that was opened outside of Prolog.
Cap the database size at 256 by default, similar to Gerrit
capping the user database. Allow this to be raised using a
flag on the command line.
By default launch into the repl similar to SWI-Prolog.
Change-Id: Icaf1ef7ff3bd2f19a7ded4735e1fc945ef7bbbb6
diff --git a/src/repl/PrologMain.java b/src/repl/PrologMain.java
index 0564913..6e4b004 100644
--- a/src/repl/PrologMain.java
+++ b/src/repl/PrologMain.java
@@ -1,13 +1,21 @@
package com.googlecode.prolog_cafe.repl;
import com.googlecode.prolog_cafe.exceptions.HaltException;
+import com.googlecode.prolog_cafe.lang.JavaObjectTerm;
import com.googlecode.prolog_cafe.lang.ListTerm;
import com.googlecode.prolog_cafe.lang.Prolog;
import com.googlecode.prolog_cafe.lang.StructureTerm;
import com.googlecode.prolog_cafe.lang.SymbolTerm;
import com.googlecode.prolog_cafe.lang.Term;
-import java.util.EnumSet;
+import java.io.BufferedReader;
+import java.io.File;
+import java.io.FileReader;
+import java.io.PrintStream;
+import java.io.PushbackReader;
+import java.util.ArrayList;
+import java.util.LinkedHashSet;
+import java.util.List;
import java.util.StringTokenizer;
/** Launches the meta-interpreter from the command line. */
@@ -18,27 +26,66 @@
public static void main(String argv[]) {
try {
System.err.println(HEADER);
- if (argv.length != 1) {
- usage();
- System.exit(1);
- }
-
- Term packages = new ListTerm(
- SymbolTerm.intern(Prolog.BUILTIN),
- new ListTerm(SymbolTerm.intern("user"), Prolog.Nil));
-
- Term goal = parseAtomicGoal(argv[0]);
- if (goal == null) {
- usage();
- System.exit(1);
- }
BlockingPrologControl p = new BlockingPrologControl();
- p.setEnabled(EnumSet.allOf(Prolog.Feature.class), true);
p.configureUserIO(System.in, System.out, System.err);
- p.setPredicate(Prolog.BUILTIN, "initialization", packages, goal);
- for (boolean r = p.call(); r; r = p.redo()) {
+ p.setMaxDatabaseSize(256);
+
+ List<File> toLoad = new ArrayList<>(4);
+ long reductionLimit = Long.MAX_VALUE;
+ Term goal = null;
+ for (int i = 0; i < argv.length; i++) {
+ String arg = argv[i];
+ if (arg.equals("--enable-io")) {
+ p.setEnabled(Prolog.Feature.IO, true);
+ } else if (arg.equals("--enable-statistics")) {
+ p.setEnabled(Prolog.Feature.STATISTICS, true);
+ } else if (arg.startsWith("--max-database-size=")) {
+ String v = arg.substring(arg.indexOf('=') + 1);
+ p.setMaxDatabaseSize(Integer.parseInt(v, 10));
+ } else if (arg.startsWith("--reduction-limit=")) {
+ String v = arg.substring(arg.indexOf('=') + 1);
+ reductionLimit = Long.parseLong(v, 10);
+ } else if (arg.equals("-f") && i + 1 < argv.length) {
+ toLoad.add(new File(argv[++i]));
+ } else if (arg.startsWith("-")) {
+ usage();
+ System.exit(1);
+ } else if (i == argv.length - 1) {
+ goal = parseAtomicGoal(arg);
+ } else {
+ usage();
+ System.exit(1);
+ }
}
+
+ initializePackages(p, goal);
+ for (File file : toLoad) {
+ try (FileReader src = new FileReader(file);
+ BufferedReader buf = new BufferedReader(src);
+ PushbackReader in = new PushbackReader(buf, Prolog.PUSHBACK_SIZE)) {
+ Term path = SymbolTerm.create(file.getPath());
+ if (!p.execute(Prolog.BUILTIN, "consult_stream",
+ path, new JavaObjectTerm(in))) {
+ System.err.println();
+ System.err.flush();
+ System.exit(1);
+ }
+ }
+ System.err.println();
+ System.err.flush();
+ }
+
+ if (goal == null) {
+ System.err.println();
+ System.err.flush();
+ goal = new StructureTerm(SymbolTerm.intern(":", 2), new Term[]{
+ SymbolTerm.intern(Prolog.BUILTIN),
+ SymbolTerm.create("cafeteria")});
+ }
+
+ p.setReductionLimit(reductionLimit);
+ p.execute(Prolog.BUILTIN, "call", goal);
} catch (HaltException e) {
System.exit(e.getStatus());
} catch (Exception e) {
@@ -73,11 +120,35 @@
}
}
+ private static void initializePackages(BlockingPrologControl p, Term goal) {
+ LinkedHashSet<String> set = new LinkedHashSet<>(3);
+ set.add(Prolog.BUILTIN);
+ set.add("user");
+ if (goal != null) {
+ set.add(goal.arg(1).name());
+ }
+
+ List<String> list = new ArrayList<>(set);
+ Term done = SymbolTerm.intern("true");
+ Term head = Prolog.Nil;
+ for (int i = list.size() - 1; 0 <= i; i--) {
+ head = new ListTerm(SymbolTerm.intern(list.get(i)), head);
+ }
+ p.execute(Prolog.BUILTIN, "initialization", head, done);
+ }
+
private static void usage() {
- System.err.println("Usage:");
- System.err.println(" java -jar cafeteria.jar package:predicate");
- System.err.println(" java -jar cafeteria.jar predicate");
- System.err.println(" package: package name\n");
- System.err.println(" predicate: predicate name (only atom)");
+ PrintStream e = System.err;
+ e.println("usage: java -jar cafeteria.jar [options] [goal]");
+ e.println();
+ e.println(" --enable-io : enable file system access");
+ e.println(" --enable-statistics : enable statistics/2");
+ e.println(" --max-database-size=N : maximum entries in dynamic database");
+ e.println(" --reduction-limit=N : max reductions during execution");
+ e.println();
+ e.println(" -f source.pl : load file.pl (may be repeated)");
+ e.println();
+ e.println(" goal : predicate or package:predicate");
+ e.println(" (if not specified, runs interactive loop)");
}
}
