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comparison src/luan/LuanBit.java @ 88:6ca02b188dba

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add LuanBit to clean up code; add repr(); git-svn-id: https://luan-java.googlecode.com/svn/trunk@89 21e917c8-12df-6dd8-5cb6-c86387c605b9
author fschmidt@gmail.com <fschmidt@gmail.com@21e917c8-12df-6dd8-5cb6-c86387c605b9>
date Wed, 27 Feb 2013 23:50:32 +0000
parents
children 2428ecfed375
comparison
equal deleted inserted replaced
87:eaf37cfa30c2 88:6ca02b188dba
1 package luan;
2
3 import java.util.List;
4
5
6 public final class LuanBit {
7 public final LuanState luan;
8 public final LuanElement el;
9
10 LuanBit(LuanState luan,LuanElement el) {
11 this.luan = luan;
12 this.el = el;
13 }
14
15 public LuanException exception(Object msg) {
16 return new LuanException(this,msg);
17 }
18
19 public Object[] call(LuanFunction fn,String fnName,Object... args) throws LuanException {
20 List<StackTraceElement> stackTrace = luan.stackTrace;
21 stackTrace.add( new StackTraceElement(el,fnName) );
22 try {
23 return fn.call(luan,args);
24 } finally {
25 stackTrace.remove(stackTrace.size()-1);
26 }
27 }
28
29 public String checkString(Object obj) throws LuanException {
30 String s = Luan.asString(obj);
31 if( s == null )
32 throw exception( "attempt to use a " + Luan.type(obj) + " as a string" );
33 return s;
34 }
35
36 public Number checkNumber(Object obj) throws LuanException {
37 Number n = Luan.toNumber(obj);
38 if( n == null )
39 throw exception( "attempt to perform arithmetic on a " + Luan.type(obj) + " value" );
40 return n;
41 }
42
43 public LuanFunction checkFunction(Object obj) throws LuanException {
44 if( obj instanceof LuanFunction )
45 return (LuanFunction)obj;
46 throw exception( "attempt to call a " + Luan.type(obj) + " value" );
47 }
48
49 public String toString(Object obj) throws LuanException {
50 LuanFunction fn = getHandlerFunction("__tostring",obj);
51 if( fn != null )
52 return checkString( Luan.first( call(fn,"__tostring",obj) ) );
53 return Luan.toString(obj);
54 }
55
56 public String repr(Object obj) throws LuanException {
57 LuanFunction fn = getHandlerFunction("__repr",obj);
58 if( fn != null )
59 return checkString( Luan.first( call(fn,"__repr",obj) ) );
60 String repr = Luan.repr(obj);
61 if( repr==null )
62 throw exception( "value '" + obj + "' doesn't support repr()" );
63 return repr;
64 }
65
66 public LuanFunction getHandlerFunction(String op,Object obj) throws LuanException {
67 Object f = luan.getHandler(op,obj);
68 if( f == null )
69 return null;
70 return checkFunction(f);
71 }
72
73 public LuanFunction getBinHandler(String op,Object o1,Object o2) throws LuanException {
74 LuanFunction f1 = getHandlerFunction(op,o1);
75 if( f1 != null )
76 return f1;
77 return getHandlerFunction(op,o2);
78 }
79
80 public boolean isLessThan(Object o1,Object o2) throws LuanException {
81 if( o1 instanceof Number && o2 instanceof Number ) {
82 Number n1 = (Number)o1;
83 Number n2 = (Number)o2;
84 return n1.doubleValue() < n2.doubleValue();
85 }
86 if( o1 instanceof String && o2 instanceof String ) {
87 String s1 = (String)o1;
88 String s2 = (String)o2;
89 return s1.compareTo(s2) < 0;
90 }
91 LuanFunction fn = getBinHandler("__lt",o1,o2);
92 if( fn != null )
93 return Luan.toBoolean( Luan.first(call(fn,"__lt",o1,o2)) );
94 throw exception( "attempt to compare " + Luan.type(o1) + " with " + Luan.type(o2) );
95 }
96
97 public Object arithmetic(String op,Object o1,Object o2) throws LuanException {
98 LuanFunction fn = getBinHandler(op,o1,o2);
99 if( fn != null )
100 return Luan.first(call(fn,op,o1,o2));
101 String type = Luan.toNumber(o1)==null ? Luan.type(o1) : Luan.type(o2);
102 throw exception("attempt to perform arithmetic on a "+type+" value");
103 }
104
105 }