| package com.googlecode.prolog_cafe.builtin; |
| import com.googlecode.prolog_cafe.lang.*; |
| /** |
| * <code>number_chars/2</code><br> |
| * @author Mutsunori Banbara (banbara@kobe-u.ac.jp) |
| * @author Naoyuki Tamura (tamura@kobe-u.ac.jp) |
| * @version 1.0 |
| */ |
| public class PRED_number_chars_2 extends Predicate.P2 { |
| public PRED_number_chars_2(Term a1, Term a2, Operation cont) { |
| arg1 = a1; |
| arg2 = a2; |
| this.cont = cont; |
| } |
| |
| public Operation exec(Prolog engine) { |
| engine.setB0(); |
| Term a1, a2; |
| a1 = arg1; |
| a2 = arg2; |
| |
| a1 = a1.dereference(); |
| a2 = a2.dereference(); |
| if (a2.isNil()) |
| throw new SyntaxException(this, 2, "character_code_list", a2, ""); |
| if (a1.isVariable()) { // number_chars(-Number, +CharList) |
| if (a2.isVariable()) { |
| throw new PInstantiationException(this, 2); |
| } else if (! a2.isList()) { |
| throw new IllegalTypeException(this, 2, "list", a2); |
| } |
| StringBuffer sb = new StringBuffer(); |
| Term x = a2; |
| while(! x.isNil()) { |
| if (x.isVariable()) |
| throw new PInstantiationException(this, 2); |
| if (! x.isList()) |
| throw new IllegalTypeException(this, 2, "list", a2); |
| Term car = ((ListTerm)x).car().dereference(); |
| if (car.isVariable()) |
| throw new PInstantiationException(this, 2); |
| if (! car.isSymbol() || ((SymbolTerm)car).name().length() != 1) |
| throw new IllegalTypeException(this, 2, "character", a2); |
| sb.append(((SymbolTerm)car).name()); |
| x = ((ListTerm)x).cdr().dereference(); |
| } |
| try { |
| if (! a1.unify(new IntegerTerm(Integer.parseInt(sb.toString())), engine.trail)) |
| return engine.fail(); |
| return cont; |
| } catch (NumberFormatException e) {} |
| try { |
| if(! a1.unify(new DoubleTerm(Double.parseDouble(sb.toString())), engine.trail)) |
| return engine.fail(); |
| return cont; |
| } catch (NumberFormatException e) { |
| throw new SyntaxException(this, 2, "character_code_list", a2, ""); |
| } |
| } else if (a1.isNumber()) { // number_chars(+Number, ?CharList) |
| String s = a1.toString(); |
| Term y = Prolog.Nil; |
| for (int i=s.length(); i>0; i--) { |
| y = new ListTerm(SymbolTerm.create(s.substring(i-1,i)), y); |
| } |
| if (! a2.unify(y, engine.trail) ) |
| return engine.fail(); |
| return cont; |
| } else { |
| throw new IllegalTypeException(this, 1, "number", a1); |
| } |
| } |
| } |