Tuprolog 和定义中缀运算符 [英] Tuprolog and defining infix operators
问题描述
所以我有一些序言...
So I have some prolog...
cobrakai$more operator.pl
be(a,c).
:-op(35,xfx,be).
+=(a,c).
:-op(35,xfx,+=).
cobrakai$
定义了一些中缀运算符.我使用 SWI prolog 运行它并得到以下(完全预期的)结果
Which defines some infix operators. I run it using SWI prolog and get the following (perfectly expected) results
?- halt.
cobrakai$swipl -s operator.pl
% library(swi_hooks) compiled into pce_swi_hooks 0.00 sec, 3,992 bytes
% /Users/josephreddington/Documents/workspace/com.plancomps.prolog.helloworld/operator.pl compiled 0.00 sec, 992 bytes
Welcome to SWI-Prolog (Multi-threaded, 64 bits, Version 5.10.5)
Copyright (c) 1990-2011 University of Amsterdam, VU Amsterdam
SWI-Prolog comes with ABSOLUTELY NO WARRANTY. This is free software,
and you are welcome to redistribute it under certain conditions.
Please visit http://www.swi-prolog.org for details.
For help, use ?- help(Topic). or ?- apropos(Word).
?- be(a,c).
true.
?- a be c.
true.
?- +=(a,c).
ERROR: toplevel: Undefined procedure: (+=)/2 (DWIM could not correct goal)
?- halt.
cobrakai$swipl -s operator.pl
% library(swi_hooks) compiled into pce_swi_hooks 0.00 sec, 3,992 bytes
% /Users/josephreddington/Documents/workspace/com.plancomps.prolog.helloworld/operator.pl compiled 0.00 sec, 1,280 bytes
Welcome to SWI-Prolog (Multi-threaded, 64 bits, Version 5.10.5)
Copyright (c) 1990-2011 University of Amsterdam, VU Amsterdam
SWI-Prolog comes with ABSOLUTELY NO WARRANTY. This is free software,
and you are welcome to redistribute it under certain conditions.
Please visit http://www.swi-prolog.org for details.
For help, use ?- help(Topic). or ?- apropos(Word).
?- be(a,c).
true.
?- a be c.
true.
?- +=(a,c).
true.
?- a += c.
true.
?- halt.
但是,当我使用 Tuprolog 处理来自 Java 的相同文件时(使用以下代码)
However, when I use Tuprolog to process the same file from Java (using the following code)
import java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;
import alice.tuprolog.Prolog;
import alice.tuprolog.SolveInfo;
import alice.tuprolog.Theory;
public class Testinfixoperatorconstruction {
public static void main(String[] args) throws Exception {
Prolog engine = new Prolog();
engine.loadLibrary("alice.tuprolog.lib.DCGLibrary");
engine.addTheory(new Theory(readFile("/Users/josephreddington/Documents/workspace/com.plancomps.prolog.helloworld/operator.pl")));
SolveInfo info = engine.solve("be(a,c).");
System.out.println(info.getSolution());
info = engine.solve("a be c.");
System.out.println(info.getSolution());
}
private static String readFile(String file) throws IOException {
BufferedReader reader = new BufferedReader(new FileReader(file));
String line = null;
StringBuilder stringBuilder = new StringBuilder();
String ls = System.getProperty("line.separator");
while ((line = reader.readLine()) != null) {
stringBuilder.append(line);
stringBuilder.append(ls);
}
return stringBuilder.toString();
}
}
prolog 文件不解析 - '+=' 标记失败.
The prolog file does not parse - failing on the '+=' token.
Exception in thread "main" alice.tuprolog.InvalidTheoryException: Unexpected token '+='
at alice.tuprolog.TheoryManager.consult(TheoryManager.java:193)
at alice.tuprolog.Prolog.addTheory(Prolog.java:242)
at Testinfixoperatorconstruction.main(Testinfixoperatorconstruction.java:14)
我们可以尝试一种稍微不同的方法,直接在java代码中添加运算符...
We can try a slightly different approach, adding the operator directly in the java code with...
public static void main(String[] args) 抛出异常 {序言引擎=新序言();engine.loadLibrary("alice.tuprolog.lib.DCGLibrary");
public static void main(String[] args) throws Exception { Prolog engine = new Prolog(); engine.loadLibrary("alice.tuprolog.lib.DCGLibrary");
engine.getOperatorManager().opNew("be", "xfx", 35);
engine.getOperatorManager().opNew("+=", "xfx", 35);
engine.addTheory(new Theory(
readFile("/Users/josephreddington/Documents/workspace/com.plancomps.prolog.helloworld/operator2.pl")));
SolveInfo info = engine.solve("be(a,c).");
System.out.println(info.getSolution());
info = engine.solve("a be c.");
System.out.println(info.getSolution());
}
但是我们得到了同样的错误... :(
but we get the same error... :(
谁能告诉我为什么会这样?(也欢迎解决方案).
Can anyone tell me why this is happening? (and solutions would also be welcome).
推荐答案
SWI-Prolog 在解析指令时可能过于宽松.尝试将运算符括在括号之间:
SWI-Prolog could be too much permissive while parsing directives. Try enclosing operators between parenthesis:
:-op(35,xfx,(+=)).
edit 我尝试使用 2p.jar,这让我发现了问题.需要引用操作符的原子:
edit I tried using 2p.jar, that allowed me to spot the problem. Need to quote operator' atom:
:-op(35,xfx, '+=').
X += Y.
p :- a += b.
交互式 2p 控制台接受此语法.注意 2p.jar 默认加载 tuprolog libraries
interactive 2p console accepts this syntax. Note that 2p.jar by default load tuprolog libraries
这篇关于Tuprolog 和定义中缀运算符的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持IT屋!