bundles/org.simantics.scl.compiler/src/org/simantics/scl/compiler/internal/parsing/parser/SCLParserImpl.java

   1 package org.simantics.scl.compiler.internal.parsing.parser;
   2
   3 import java.io.Reader;
   4 import java.util.ArrayList;
   5 import java.util.Arrays;
   6 import java.util.List;
   7
   8 import org.simantics.scl.compiler.common.exceptions.InternalCompilerError;
   9 import org.simantics.scl.compiler.common.precedence.Associativity;
  10 import org.simantics.scl.compiler.common.precedence.Precedence;
  11 import org.simantics.scl.compiler.compilation.CompilationContext;
  12 import org.simantics.scl.compiler.constants.CharacterConstant;
  13 import org.simantics.scl.compiler.constants.StringConstant;
  14 import org.simantics.scl.compiler.elaboration.equation.EqBasic;
  15 import org.simantics.scl.compiler.elaboration.equation.EqGuard;
  16 import org.simantics.scl.compiler.elaboration.equation.Equation;
  17 import org.simantics.scl.compiler.elaboration.expressions.Case;
  18 import org.simantics.scl.compiler.elaboration.expressions.EApply;
  19 import org.simantics.scl.compiler.elaboration.expressions.EAsPattern;
  20 import org.simantics.scl.compiler.elaboration.expressions.EBinary;
  21 import org.simantics.scl.compiler.elaboration.expressions.EBinaryRightSide;
  22 import org.simantics.scl.compiler.elaboration.expressions.EBlock;
  23 import org.simantics.scl.compiler.elaboration.expressions.EConstant;
  24 import org.simantics.scl.compiler.elaboration.expressions.EEnforce;
  25 import org.simantics.scl.compiler.elaboration.expressions.EEquations;
  26 import org.simantics.scl.compiler.elaboration.expressions.EFieldAccess;
  27 import org.simantics.scl.compiler.elaboration.expressions.EIf;
  28 import org.simantics.scl.compiler.elaboration.expressions.EIntegerLiteral;
  29 import org.simantics.scl.compiler.elaboration.expressions.ELambda;
  30 import org.simantics.scl.compiler.elaboration.expressions.EListComprehension;
  31 import org.simantics.scl.compiler.elaboration.expressions.EListLiteral;
  32 import org.simantics.scl.compiler.elaboration.expressions.ELiteral;
  33 import org.simantics.scl.compiler.elaboration.expressions.EMatch;
  34 import org.simantics.scl.compiler.elaboration.expressions.EPreCHRSelect;
  35 import org.simantics.scl.compiler.elaboration.expressions.ERange;
  36 import org.simantics.scl.compiler.elaboration.expressions.ERealLiteral;
  37 import org.simantics.scl.compiler.elaboration.expressions.ERecord;
  38 import org.simantics.scl.compiler.elaboration.expressions.ESelect;
  39 import org.simantics.scl.compiler.elaboration.expressions.ESimpleLambda;
  40 import org.simantics.scl.compiler.elaboration.expressions.EStringLiteral;
  41 import org.simantics.scl.compiler.elaboration.expressions.ETransformation;
  42 import org.simantics.scl.compiler.elaboration.expressions.ETypeAnnotation;
  43 import org.simantics.scl.compiler.elaboration.expressions.EVar;
  44 import org.simantics.scl.compiler.elaboration.expressions.EVariable;
  45 import org.simantics.scl.compiler.elaboration.expressions.EViewPattern;
  46 import org.simantics.scl.compiler.elaboration.expressions.Expression;
  47 import org.simantics.scl.compiler.elaboration.expressions.GuardedExpression;
  48 import org.simantics.scl.compiler.elaboration.expressions.GuardedExpressionGroup;
  49 import org.simantics.scl.compiler.elaboration.expressions.Variable;
  50 import org.simantics.scl.compiler.elaboration.expressions.accessor.ExpressionAccessor;
  51 import org.simantics.scl.compiler.elaboration.expressions.accessor.FieldAccessor;
  52 import org.simantics.scl.compiler.elaboration.expressions.accessor.IdAccessor;
  53 import org.simantics.scl.compiler.elaboration.expressions.accessor.StringAccessor;
  54 import org.simantics.scl.compiler.elaboration.expressions.block.BindStatement;
  55 import org.simantics.scl.compiler.elaboration.expressions.block.CHRStatement;
  56 import org.simantics.scl.compiler.elaboration.expressions.block.ConstraintStatement;
  57 import org.simantics.scl.compiler.elaboration.expressions.block.GuardStatement;
  58 import org.simantics.scl.compiler.elaboration.expressions.block.IncludeStatement;
  59 import org.simantics.scl.compiler.elaboration.expressions.block.LetStatement;
  60 import org.simantics.scl.compiler.elaboration.expressions.block.RuleStatement;
  61 import org.simantics.scl.compiler.elaboration.expressions.block.Statement;
  62 import org.simantics.scl.compiler.elaboration.expressions.list.ListAssignment;
  63 import org.simantics.scl.compiler.elaboration.expressions.list.ListGenerator;
  64 import org.simantics.scl.compiler.elaboration.expressions.list.ListGuard;
  65 import org.simantics.scl.compiler.elaboration.expressions.list.ListQualifier;
  66 import org.simantics.scl.compiler.elaboration.expressions.list.ListSeq;
  67 import org.simantics.scl.compiler.elaboration.expressions.list.ListThen;
  68 import org.simantics.scl.compiler.elaboration.expressions.records.FieldAssignment;
  69 import org.simantics.scl.compiler.elaboration.java.Builtins;
  70 import org.simantics.scl.compiler.elaboration.query.QAlternative;
  71 import org.simantics.scl.compiler.elaboration.query.QConjunction;
  72 import org.simantics.scl.compiler.elaboration.query.QDisjunction;
  73 import org.simantics.scl.compiler.elaboration.query.QNegation;
  74 import org.simantics.scl.compiler.elaboration.query.Query;
  75 import org.simantics.scl.compiler.elaboration.query.pre.QPreBinds;
  76 import org.simantics.scl.compiler.elaboration.query.pre.QPreEquals;
  77 import org.simantics.scl.compiler.elaboration.query.pre.QPreGuard;
  78 import org.simantics.scl.compiler.errors.Locations;
  79 import org.simantics.scl.compiler.internal.header.ModuleHeader;
  80 import org.simantics.scl.compiler.internal.parsing.Symbol;
  81 import org.simantics.scl.compiler.internal.parsing.Token;
  82 import org.simantics.scl.compiler.internal.parsing.declarations.ConstructorAst;
  83 import org.simantics.scl.compiler.internal.parsing.declarations.DAnnotationAst;
  84 import org.simantics.scl.compiler.internal.parsing.declarations.DClassAst;
  85 import org.simantics.scl.compiler.internal.parsing.declarations.DDataAst;
  86 import org.simantics.scl.compiler.internal.parsing.declarations.DDerivingInstanceAst;
  87 import org.simantics.scl.compiler.internal.parsing.declarations.DDocumentationAst;
  88 import org.simantics.scl.compiler.internal.parsing.declarations.DEffectAst;
  89 import org.simantics.scl.compiler.internal.parsing.declarations.DFixityAst;
  90 import org.simantics.scl.compiler.internal.parsing.declarations.DImportJavaAst;
  91 import org.simantics.scl.compiler.internal.parsing.declarations.DInstanceAst;
  92 import org.simantics.scl.compiler.internal.parsing.declarations.DMappingRelationAst;
  93 import org.simantics.scl.compiler.internal.parsing.declarations.DRelationAst;
  94 import org.simantics.scl.compiler.internal.parsing.declarations.DRuleAst;
  95 import org.simantics.scl.compiler.internal.parsing.declarations.DRulesetAst;
  96 import org.simantics.scl.compiler.internal.parsing.declarations.DTypeAst;
  97 import org.simantics.scl.compiler.internal.parsing.declarations.DValueAst;
  98 import org.simantics.scl.compiler.internal.parsing.declarations.DValueTypeAst;
  99 import org.simantics.scl.compiler.internal.parsing.declarations.DeclarationAst;
 100 import org.simantics.scl.compiler.internal.parsing.declarations.FieldDescription;
 101 import org.simantics.scl.compiler.internal.parsing.declarations.FundepAst;
 102 import org.simantics.scl.compiler.internal.parsing.exceptions.SCLSyntaxErrorException;
 103 import org.simantics.scl.compiler.internal.parsing.types.TApplyAst;
 104 import org.simantics.scl.compiler.internal.parsing.types.TEffectAst;
 105 import org.simantics.scl.compiler.internal.parsing.types.TForAllAst;
 106 import org.simantics.scl.compiler.internal.parsing.types.TFunctionAst;
 107 import org.simantics.scl.compiler.internal.parsing.types.TListAst;
 108 import org.simantics.scl.compiler.internal.parsing.types.TPredAst;
 109 import org.simantics.scl.compiler.internal.parsing.types.TTupleAst;
 110 import org.simantics.scl.compiler.internal.parsing.types.TVarAst;
 111 import org.simantics.scl.compiler.internal.parsing.types.TypeAst;
 112 import org.simantics.scl.compiler.module.ImportDeclaration;
 113 import org.simantics.scl.compiler.types.Types;
 114
 115
 116 public class SCLParserImpl extends SCLParser {
 117
 118     private final SCLPostLexer lexer;
 119     private SCLParserOptions options;
 120     private CompilationContext context;
 121
 122     public SCLParserImpl(Reader reader) {
 123         this.lexer = new SCLPostLexer(reader);
 124     }
 125
 126     public void setCompilationContext(CompilationContext context) {
 127         this.context = context;
 128         lexer.setCompilationContext(context);
 129     }
 130
 131     public void setParserOptions(SCLParserOptions options) {
 132         this.options = options;
 133         lexer.setParserOptions(options);
 134     }
 135
 136     public boolean isEmpty() throws Exception {
 137         return lexer.peekToken().id == SCLTerminals.EOF;
 138     }
 139
 140     @Override
 141     protected Token nextToken() {
 142         try {
 143             Token token = lexer.nextToken();
 144             /*System.out.println("TOKEN " + token.text + " (" + TERMINAL_NAMES[token.id] + ")" +
 145                     " ["
 146                     + Locations.beginOf(token.location) + ".."
 147                     + Locations.endOf(token.location) + "]");*/
 148             return token;
 149         } catch(Exception e) {
 150             if(e instanceof RuntimeException)
 151                 throw (RuntimeException)e;
 152             else
 153                 throw new RuntimeException(e);
 154         }
 155     }
 156
 157     @Override
 158     protected Object reduceDeclarations() {
 159         ArrayList<DeclarationAst> declarations = new ArrayList<DeclarationAst>(length()/2);
 160         for(int i=1;i<length();i+=2)
 161             declarations.add((DeclarationAst)get(i));
 162         return declarations;
 163     }
 164
 165     @Override
 166     protected Object reduceModule() {
 167         ArrayList<DeclarationAst> declarations = new ArrayList<DeclarationAst>(length()/2+1);
 168         for(int i=0;i<length();i+=2) {
 169             DeclarationAst declaration = (DeclarationAst)get(i);
 170             if(declaration == null)
 171                 continue;
 172             declarations.add(declaration);
 173         }
 174         return declarations;
 175     }
 176
 177     @Override
 178     protected Object reduceModuleHeader() {
 179         FieldAssignment[] fields = new FieldAssignment[length()/2-1];
 180         for(int i=0;i<fields.length;++i)
 181             fields[i] = (FieldAssignment)get(2+i*2);
 182         context.header = ModuleHeader.process(context.errorLog, fields);
 183         return null;
 184     }
 185
 186     @Override
 187     protected Object reduceLocalTypeAnnotation() {
 188         if(length() == 1)
 189             return get(0);
 190         return new ETypeAnnotation((Expression)get(0), (TypeAst)get(2));
 191     }
 192
 193     @Override
 194     protected Object reduceTypeAnnotation() {
 195         EVar[] names = new EVar[length()/2];
 196         for(int i=0;i<names.length;++i)
 197             names[i] = (EVar)get(i*2);
 198         return new DValueTypeAst(
 199                 names,
 200                 (TypeAst)get(length()-1)
 201                 );
 202     }
 203
 204     @Override
 205     protected Object reduceValueDefinition() {
 206         Expression rhs = (Expression)get(1);
 207         return new DValueAst((Expression)get(0), rhs);
 208     }
 209
 210     @Override
 211     protected Object reduceDataDefinition() {
 212         int i=2;
 213         ArrayList<String> parameters = new ArrayList<String>();
 214         while(i < length()) {
 215             Token token = (Token)get(i++);
 216             if(token.id != SCLTerminals.ID)
 217                 break;
 218             parameters.add(token.text);
 219         }
 220         ArrayList<ConstructorAst> constructors = new ArrayList<ConstructorAst>();
 221         for(;i < length();i+=2)
 222             constructors.add((ConstructorAst)get(i));
 223         return new DDataAst(
 224                 ((Token)get(1)).text,
 225                 parameters.toArray(new String[parameters.size()]),
 226                 constructors.toArray(new ConstructorAst[constructors.size()]),
 227                 new String[0]
 228                 );
 229     }
 230
 231     @Override
 232     protected Object reduceTypeDefinition() {
 233         int i=2;
 234         ArrayList<String> parameters = new ArrayList<String>();
 235         while(true) {
 236             Token token = (Token)get(i++);
 237             if(token.id != SCLTerminals.ID)
 238                 break;
 239             parameters.add(token.text);
 240         }
 241         return new DTypeAst(
 242                 ((Token)get(1)).text,
 243                 parameters.toArray(new String[parameters.size()]),
 244                 (TypeAst)get(i)
 245                 );
 246     }
 247
 248     @SuppressWarnings("unchecked")
 249     @Override
 250     protected Object reduceClassDefinition() {
 251         int i=1;
 252         ArrayList<TypeAst> context;
 253         if(get(i) instanceof Token)
 254             context = new ArrayList<TypeAst>(0);
 255         else
 256             context = (ArrayList<TypeAst>)get(i++);
 257         String name = ((Token)get(i++)).text;
 258         ArrayList<String> parameters = new ArrayList<String>();
 259         while(i < length()) {
 260             Token token = (Token)get(i);
 261             if(token.id != SCLTerminals.ID)
 262                 break;
 263             parameters.add(token.text);
 264             ++i;
 265         }
 266         ArrayList<DeclarationAst> declarations = null;
 267         FundepAst[] fundeps = FundepAst.EMPTY_ARRAY;
 268         while(i < length()) {
 269             Token token = (Token)get(i++);
 270             if(token.id == SCLTerminals.WHERE) {
 271                 declarations = (ArrayList<DeclarationAst>)get(i++);
 272             }
 273             else if(token.id == SCLTerminals.BAR) {
 274                 fundeps = (FundepAst[])get(i++);
 275             }
 276             else
 277                 throw new InternalCompilerError();
 278         }
 279         return new DClassAst(context, name,
 280                 parameters.toArray(new String[parameters.size()]),
 281                 fundeps,
 282                 declarations);
 283     }
 284
 285     @Override
 286     protected Object reduceFundep() {
 287         String[] from = new String[length()-2];
 288         for(int i=0;i<from.length;++i)
 289             from[i] = ((Token)get(i)).text;
 290         String to = ((Token)get(length()-1)).text;
 291         return new FundepAst(from, to);
 292     }
 293
 294     @Override
 295     protected Object reduceFundeps() {
 296         FundepAst[] fundeps = new FundepAst[(length()+1)/2];
 297         for(int i=0;i<fundeps.length;++i)
 298             fundeps[i] = (FundepAst)get(i*2);
 299         return fundeps;
 300     }
 301
 302     @SuppressWarnings("unchecked")
 303     @Override
 304     protected Object reduceInstanceDefinition() {
 305         int i=1;
 306         ArrayList<TypeAst> context;
 307         if(get(i) instanceof Token)
 308             context = new ArrayList<TypeAst>(0);
 309         else
 310             context = (ArrayList<TypeAst>)get(i++);
 311         Token nameToken = (Token)get(i++);
 312         EVar name = new EVar(nameToken);
 313         ArrayList<TypeAst> parameters = new ArrayList<TypeAst>();
 314         while(i < length()) {
 315             Object symbol = get(i++);
 316             if(symbol instanceof Token)
 317                 break;
 318             parameters.add((TypeAst)symbol);
 319         }
 320         ArrayList<DeclarationAst> declarations = null;
 321         if(i < length())
 322             declarations = (ArrayList<DeclarationAst>)get(i);
 323         return new DInstanceAst(context, name,
 324                 parameters.toArray(new TypeAst[parameters.size()]),
 325                 declarations);
 326     }
 327
 328     @SuppressWarnings("unchecked")
 329     @Override
 330     protected Object reduceDerivingInstanceDefinition() {
 331         int i=2;
 332         ArrayList<TypeAst> context;
 333         if(get(i) instanceof Token)
 334             context = new ArrayList<TypeAst>(0);
 335         else
 336             context = (ArrayList<TypeAst>)get(i++);
 337         Token nameToken = (Token)get(i++);
 338         EVar name = new EVar(nameToken);
 339         ArrayList<TypeAst> parameters = new ArrayList<TypeAst>();
 340         while(i < length()) {
 341             Object symbol = get(i++);
 342             parameters.add((TypeAst)symbol);
 343         }
 344         return new DDerivingInstanceAst(context, name,
 345                 parameters.toArray(new TypeAst[parameters.size()]));
 346     }
 347
 348     @Override
 349     protected Object reduceDocumentationString() {
 350         return new DDocumentationAst(((Token)get(1)).text);
 351     }
 352
 353     @Override
 354     protected Object reduceAnnotation() {
 355         ArrayList<Expression> parameters = new ArrayList<Expression>(length()-1);
 356         for(int i=1;i<length();++i)
 357             parameters.add((Expression)get(i));
 358         return new DAnnotationAst((Token)get(0), parameters);
 359     }
 360
 361     @Override
 362     protected Object reducePrecedenceDefinition() {
 363         EVar[] symbols = new EVar[length()/2];
 364         for(int i=0;i<symbols.length;++i)
 365             symbols[i] = (EVar)get(2*i + 2);
 366         Associativity associativity;
 367         Token token = (Token)get(0);
 368         if(token.text.equals("infixl"))
 369             associativity = Associativity.LEFT;
 370         else if(token.text.equals("infixr"))
 371             associativity = Associativity.RIGHT;
 372         else
 373             associativity = Associativity.NONASSOC;
 374         return new DFixityAst(
 375                 new Precedence(
 376                         Integer.parseInt(((Token)get(1)).text),
 377                         associativity),
 378                         symbols);
 379     }
 380
 381     @Override
 382     protected Object reduceImport() {
 383         // (AS ID)? importSpec?
 384         int pos = 0;
 385         String importKeyword = ((Token)get(pos++)).text; // (IMPORT | INCLUDE)
 386         ++pos; // BEGIN_STRING
 387         String moduleName = ((Token)get(pos++)).text; // END_STRING
 388         String localName = "";
 389         if(pos < length()) {
 390             Object temp = get(pos);
 391             if(temp instanceof Token) {
 392                 Token token = (Token)temp;
 393                 if(token.id == SCLTerminals.AS) {
 394                     ++pos; // AS
 395                     localName = ((Token)get(pos++)).text; // ID
 396                 }
 397             }
 398         }
 399         ImportDeclaration.ImportSpec spec = ImportDeclaration.DEFAULT_SPEC;
 400         if(pos < length())
 401             spec = (ImportDeclaration.ImportSpec)get(pos++);
 402         return new ImportDeclaration(moduleName, localName,
 403                         importKeyword.equals("include"),
 404                         spec);
 405     }
 406
 407     @Override
 408     protected Object reduceJustImport() {
 409         return get(0);
 410     }
 411
 412     @SuppressWarnings("unchecked")
 413     @Override
 414     protected Object reduceImportJava() {
 415         return new DImportJavaAst(((Token)get(2)).text, (ArrayList<DeclarationAst>)get(4));
 416     }
 417
 418     @Override
 419     protected Object reduceEffectDefinition() {
 420         return new DEffectAst(
 421                 ((Token)get(1)).text,
 422                 ((Token)get(3)).text,
 423                 ((Token)get(5)).text);
 424     }
 425
 426     @Override
 427     protected Object reduceVarId() {
 428         return new EVar((Token)get(0));
 429     }
 430
 431     @Override
 432     protected Object reduceEscapedSymbol() {
 433         return new EVar((Token)get(0));
 434     }
 435
 436     @Override
 437     protected Object reduceTupleTypeConstructor() {
 438         return new TVarAst(Types.tupleConstructor(length()-1).name);
 439     }
 440
 441     @Override
 442     protected Object reduceArrow() {
 443         int i=length()-1;
 444         TypeAst result = (TypeAst)get(i);
 445         i-=2;
 446         while(i >= 0) {
 447             if( ((Token)get(i+1)).text.equals("=>") )
 448                 result = new TPredAst((TypeAst)get(i), result);
 449             else
 450                 result = new TFunctionAst((TypeAst)get(i), result);
 451             i-=2;
 452         }
 453         return result;
 454     }
 455
 456     @Override
 457     protected Object reduceBinary() {
 458         if(length() == 1)
 459             return get(0);
 460         int i=0;
 461         EVar negation = null;
 462         if(get(i) instanceof Token) {
 463             Token token = (Token)get(i++);
 464             negation = new EVar(token);
 465         }
 466         EBinary binary = new EBinary((Expression)get(i++), negation);
 467         while(i < length()) {
 468             EVar operator = (EVar)get(i++);
 469             Expression right = (Expression)get(i++);
 470             binary.rights.add(new EBinaryRightSide(operator, right));
 471         }
 472         return binary;
 473     }
 474
 475     @Override
 476     protected Object reduceSimpleRhs() {
 477         if(length() == 2)
 478             return get(1);
 479         else {
 480             EBlock block = (EBlock)get(3);
 481             Expression expression = (Expression)get(1);
 482             block.addStatement(new GuardStatement(expression));
 483             block.location = Locations.location(Locations.beginOf(expression.location), Locations.endOf(block.location));
 484             return block;
 485         }
 486     }
 487
 488     private GuardedExpressionGroup reduceGuardedExpressionGroup(int length) {
 489         GuardedExpression[] expressions = new GuardedExpression[length];
 490         for(int i=0;i<expressions.length;++i) {
 491             expressions[i] = (GuardedExpression)get(i);
 492         }
 493         return new GuardedExpressionGroup(expressions);
 494     }
 495
 496     @Override
 497     protected Object reduceGuardedRhs() {
 498         int length = length();
 499         if(length > 2 && get(length-2) instanceof Token) {
 500             EBlock block = (EBlock)get(length-1);
 501             block.addStatement(new GuardStatement(reduceGuardedExpressionGroup(length-2)));
 502             block.location = Locations.NO_LOCATION;
 503             return block;
 504         }
 505         else
 506             return reduceGuardedExpressionGroup(length);
 507     }
 508
 509     @Override
 510     protected Object reduceStatements() {
 511         EBlock block = new EBlock();
 512         if(length() > 2)
 513             for(int i=1;i<length();i+=2)
 514                 block.addStatement((Statement)get(i));
 515         return block;
 516     }
 517
 518     @Override
 519     protected Object reduceConstructor() {
 520         int idPos;
 521         for(idPos=0;idPos<length();idPos+=2)
 522             if(((Token)get(idPos)).id == SCLTerminals.ID)
 523                 break;
 524         DAnnotationAst[] annotations = idPos == 0 ? DAnnotationAst.EMPTY_ARRAY : new DAnnotationAst[idPos/2];
 525         for(int i=0;i<idPos/2;++i)
 526             annotations[i] = new DAnnotationAst((Token)get(i*2),
 527                     Arrays.asList((Expression)get(i*2+1)));
 528         TypeAst[] parameters = new TypeAst[length()-idPos-1];
 529         for(int i=0;i<parameters.length;++i)
 530             parameters[i] = (TypeAst)get(i+idPos+1);
 531         return new ConstructorAst(annotations, (Token)get(idPos), parameters, null);
 532     }
 533
 534     @Override
 535     protected Object reduceContext() {
 536         ArrayList<TypeAst> result = new ArrayList<TypeAst>(length()/2-1);
 537         for(int i=1;i<length()-2;i+=2)
 538             result.add((TypeAst)get(i));
 539         return result;
 540     }
 541
 542     @Override
 543     protected Object reduceTypeVar() {
 544         return new TVarAst(((Token)get(0)).text);
 545     }
 546
 547     @Override
 548     protected Object reduceTupleType() {
 549         if(length() == 2)
 550             return new TTupleAst(TypeAst.EMPTY_ARRAY);
 551         if(length() == 3) {
 552             Symbol sym = (Symbol)get(1);
 553             sym.location = Locations.NO_LOCATION;
 554             return sym;
 555         }
 556         int dim = length()/2;
 557         TypeAst[] parameters = new TypeAst[dim];
 558         for(int i=0;i<dim;++i)
 559             parameters[i] = (TypeAst)get(i*2+1);
 560         return new TTupleAst(parameters);
 561     }
 562
 563     @Override
 564     protected Object reduceListType() {
 565         return new TListAst((TypeAst)get(1));
 566     }
 567
 568     @Override
 569     protected Object reduceListTypeConstructor() {
 570         return new TVarAst("[]");
 571     }
 572
 573     @Override
 574     protected Object reduceTupleConstructor() {
 575         return new EVar(Types.tupleConstructor(length()-1).name);
 576     }
 577
 578     @Override
 579     protected Object reduceVar() {
 580         return get(0);
 581     }
 582
 583     @Override
 584     protected Object reduceBlank() {
 585         return new EVar(((Token)get(0)).location, "_");
 586     }
 587
 588     @Override
 589     protected Object reduceInteger() {
 590         return new EIntegerLiteral(((Token)get(0)).text);
 591     }
 592
 593     @Override
 594     protected Object reduceFloat() {
 595         return new ERealLiteral(((Token)get(0)).text);
 596     }
 597
 598     @Override
 599     protected Object reduceString() {
 600         return get(0);
 601     }
 602
 603     @Override
 604     protected Object reduceChar() {
 605         String text = ((Token)get(0)).text;
 606         char c = text.charAt(text.length()-2);
 607         if(text.length() == 4) {
 608             switch(c) {
 609             case 'n': c = '\n'; break;
 610             case 't': c = '\t'; break;
 611             case 'b': c = '\b'; break;
 612             case 'f': c = '\f'; break;
 613             case 'r': c = '\r'; break;
 614             }
 615         }
 616         return new ELiteral(new CharacterConstant(c));
 617     }
 618
 619     @Override
 620     protected Object reduceTuple() {
 621         if(length() == 2)
 622             return new EConstant(Builtins.TUPLE_CONSTRUCTORS[0]);
 623         if(length() == 3) {
 624             Symbol sym = (Symbol)get(1);
 625             sym.location = Locations.NO_LOCATION;
 626             return sym;
 627         }
 628         int dim = length()/2;
 629         Expression[] parameters = new Expression[dim];
 630         for(int i=0;i<dim;++i)
 631             parameters[i] = (Expression)get(i*2+1);
 632         EConstant tupleConstructor = new EConstant(Builtins.TUPLE_CONSTRUCTORS[dim]);
 633         tupleConstructor.location = Locations.location(
 634                 Locations.beginOf(((Token)get(0)).location),
 635                 Locations.endOf(((Token)get(length()-1)).location));
 636         return new EApply(tupleConstructor, parameters);
 637     }
 638
 639     public static Expression rightSection(EVar op, Expression e) {
 640         long loc = Locations.combine(op.location, e.location);
 641         Variable var = new Variable("rightSectionTemp");
 642         return new ESimpleLambda(loc, var,
 643                 new EApply(loc, op, new EVariable(loc, var), e));
 644     }
 645
 646     @Override
 647     protected Object reduceRightSection() {
 648         Variable var = new Variable("rightSectionTemp");
 649         long loc = Locations.combine(((Token)get(0)).location, ((Token)get(length()-1)).location);
 650         EVar symbol = (EVar)get(1);
 651         return new ESimpleLambda(var,
 652                 new EApply(loc, symbol,
 653                         new EVariable(loc, var), (Expression)get(2)));
 654     }
 655
 656     @Override
 657     protected Object reduceLeftSection() {
 658         return new EApply((EVar)get(2), (Expression)get(1));
 659     }
 660
 661     @Override
 662     protected Object reduceListLiteral() {
 663         if(length() == 2)
 664             return new EListLiteral(Expression.EMPTY_ARRAY);
 665         int dim = length()/2;
 666         Expression[] components = new Expression[dim];
 667         for(int i=0;i<dim;++i)
 668             components[i] = (Expression)get(i*2+1);
 669         return new EListLiteral(components);
 670     }
 671
 672     @Override
 673     protected Object reduceRange() {
 674         return new ERange(
 675                 (Expression)get(1),
 676                 (Expression)get(3)
 677                 );
 678     }
 679
 680     @Override
 681     protected Object reduceListComprehension() {
 682         ListQualifier qualifier = (ListQualifier)get(3);
 683         for(int i=5;i<length();i+=2) {
 684             ListQualifier right = (ListQualifier)get(i);
 685             if(right instanceof ListThen) {
 686                 ((ListThen) right).setLeft(qualifier);
 687                 qualifier = right;
 688             }
 689             else
 690                 qualifier = new ListSeq(qualifier, right);
 691         }
 692         return new EListComprehension((Expression)get(1), qualifier);
 693     }
 694
 695     @Override
 696     protected Object reduceAs() {
 697         Token id = (Token)get(0);
 698         return new EAsPattern(new EVar(id.location, id.text), (Expression)get(2));
 699     }
 700
 701     @Override
 702     protected Object reduceGuardedExpEq() {
 703         Expression[] guards = new Expression[length()/2-1];
 704         for(int i=0;i<guards.length;++i)
 705             guards[i] = (Expression)get(i*2+1);
 706         return new GuardedExpression(guards, (Expression)get(length()-1));
 707     }
 708
 709     @Override
 710     protected Object reduceLambda() {
 711         Expression[] patterns = new Expression[length()-3];
 712         for(int i=0;i<patterns.length;++i)
 713             patterns[i] = (Expression)get(i+1);
 714         Case case_ = new Case(patterns, (Expression)get(length()-1));
 715         case_.setLhs(Locations.combine(patterns[0].location, patterns[patterns.length-1].location));
 716         return new ELambda(case_);
 717     }
 718
 719     @Override
 720     protected Object reduceLambdaMatch() {
 721         Case[] cases = new Case[length()/2-1];
 722         for(int i=0;i<cases.length;++i)
 723             cases[i] = (Case)get(i*2+2);
 724         return new ELambda(cases);
 725     }
 726
 727     @Override
 728     protected Object reduceLet() {
 729         EBlock block = (EBlock)get(1);
 730         Expression expression = (Expression)get(3);
 731         block.addStatement(new GuardStatement(expression));
 732         Token letToken = (Token)get(0);
 733         block.location = Locations.location(
 734                 Locations.beginOf(letToken.location),
 735                 Locations.endOf(expression.location));
 736         return block;
 737     }
 738
 739     @Override
 740     protected Object reduceIf() {
 741         return new EIf(
 742                 (Expression)get(1),
 743                 (Expression)get(3),
 744                 length() == 6 ? (Expression)get(5) : null);
 745     }
 746
 747     @Override
 748     protected Object reduceMatch() {
 749         Case[] cases = new Case[length()/2-2];
 750         for(int i=0;i<cases.length;++i)
 751             cases[i] = (Case)get(i*2+4);
 752         return new EMatch((Expression)get(1), cases);
 753     }
 754
 755     @Override
 756     protected Object reduceDo() {
 757         EBlock block = (EBlock)get(1);
 758         Token doToken = (Token)get(0);
 759         block.setMonadic( doToken.text.equals("mdo") );
 760         block.location = Locations.location(Locations.beginOf(doToken.location), Locations.endOf(block.location));
 761         return block;
 762     }
 763
 764     @Override
 765     protected Object reduceSelect() {
 766         return new ESelect(((Token)get(0)).id, (Expression)get(1), new QConjunction((Query[])get(3)));
 767     }
 768
 769     @Override
 770     protected Object reduceEnforce() {
 771         return new EEnforce(new QConjunction((Query[])get(1)));
 772     }
 773
 774     @Override
 775     protected Object reduceApply() {
 776         if(length() == 1)
 777             return get(0);
 778         Expression[] parameters = new Expression[length()-1];
 779         for(int i=0;i<parameters.length;++i)
 780             parameters[i] = (Expression)get(i+1);
 781         return new EApply((Expression)get(0), parameters);
 782     }
 783
 784     @Override
 785     protected Object reduceSymbol() {
 786         return new EVar(((Token)get(0)).text);
 787     }
 788
 789     @Override
 790     protected Object reduceEscapedId() {
 791         return new EVar(((Token)get(0)).text);
 792     }
 793
 794     @Override
 795     protected Object reduceMinus() {
 796         return new EVar(((Token)get(0)).text);
 797     }
 798
 799     @Override
 800     protected Object reduceLess() {
 801         return new EVar(((Token)get(0)).text);
 802     }
 803
 804     @Override
 805     protected Object reduceGreater() {
 806         return new EVar(((Token)get(0)).text);
 807     }
 808
 809     @Override
 810     protected Object reduceDot() {
 811         return new EVar(((Token)get(0)).text);
 812     }
 813
 814     @Override
 815     protected Object reduceCase() {
 816         return new Case((Expression)get(0), (Expression)get(1));
 817     }
 818
 819     @Override
 820     protected Object reduceGuardQualifier() {
 821         return new ListGuard((Expression)get(0));
 822     }
 823
 824     @Override
 825     protected Object reduceLetQualifier() {
 826         return new ListAssignment((Expression)get(0), (Expression)get(2));
 827     }
 828
 829     @Override
 830     protected Object reduceBindQualifier() {
 831         return new ListGenerator((Expression)get(0), (Expression)get(2));
 832     }
 833
 834     @Override
 835     protected Object reduceThenQualifier() {
 836         return new ListThen((Expression)get(1), length()==4 ? (Expression)get(3) : null);
 837     }
 838
 839     @Override
 840     protected Object reduceGuardStatement() {
 841         return new GuardStatement((Expression)get(0));
 842     }
 843
 844     @Override
 845     protected Object reduceLetStatement() {
 846         return new LetStatement((Expression)get(0), (Expression)get(1));
 847     }
 848
 849     @Override
 850     protected Object reduceBindStatement() {
 851         return new BindStatement((Expression)get(0), (Expression)get(2));
 852     }
 853
 854     @Override
 855     protected Object reduceSimpleCaseRhs() {
 856         return get(1);
 857     }
 858
 859     @Override
 860     protected Object reduceGuardedCaseRhs() {
 861         GuardedExpression[] expressions = new GuardedExpression[length()];
 862         for(int i=0;i<expressions.length;++i)
 863             expressions[i] = (GuardedExpression)get(i);
 864         return new GuardedExpressionGroup(expressions);
 865     }
 866
 867     @Override
 868     protected Object reduceGuardedExpArrow() {
 869         Expression[] guards = new Expression[length()/2-1];
 870         for(int i=0;i<guards.length;++i)
 871             guards[i] = (Expression)get(i*2+1);
 872         return new GuardedExpression(guards, (Expression)get(length()-1));
 873     }
 874
 875     @Override
 876     protected Object reduceEffect() {
 877         ArrayList<TypeAst> effects = new ArrayList<TypeAst>(length()/2-1);
 878         for(int i=1;i<length()-1;i+=2) {
 879             Token token = (Token)get(i);
 880             TVarAst ast = new TVarAst(token.text);
 881             ast.location = token.location;
 882             effects.add(ast);
 883         }
 884         return new TEffectAst(effects, (TypeAst)get(length()-1));
 885     }
 886
 887     @Override
 888     protected Object reduceJustEtype() {
 889         return get(0);
 890     }
 891
 892     @Override
 893     protected Object reduceForAll() {
 894         String[] vars = new String[length()-3];
 895         for(int i=0;i<vars.length;++i)
 896             vars[i] = ((Token)get(i+1)).text;
 897         return new TForAllAst(vars, (TypeAst)get(length()-1));
 898     }
 899
 900     @Override
 901     protected Object reduceApplyType() {
 902         TypeAst[] parameters = new TypeAst[length()-1];
 903         for(int i=0;i<parameters.length;++i)
 904             parameters[i] = (TypeAst)get(i+1);
 905         return new TApplyAst((TypeAst)get(0), parameters);
 906     }
 907
 908     @SuppressWarnings("unchecked")
 909     @Override
 910     protected void postReduce(Object reduced) {
 911         if(!(reduced instanceof Symbol))
 912             return;
 913         Symbol sym = (Symbol)reduced;
 914         if(sym.location != Locations.NO_LOCATION || length() == 0)
 915             return;
 916         Object first = get(0);
 917         if(!(first instanceof Symbol)) {
 918             if(first instanceof List) {
 919                 List<Object> ll = (List<Object>)first;
 920                 first = ll.get(0);
 921             }
 922             else {
 923                 Object[] ll = (Object[])first;
 924                 if(ll.length > 0)
 925                     first = ll[0];
 926                 else
 927                     first = get(1);
 928             }
 929         }
 930         Object last = get(length()-1);
 931         if(!(last instanceof Symbol)) {
 932             if(last instanceof List) {
 933                 List<Object> ll = (List<Object>)last;
 934                 last = ll.get(ll.size()-1);
 935             }
 936             else {
 937                 Object[] ll = (Object[])last;
 938                 if(ll.length > 0)
 939                     last = ll[ll.length-1];
 940                 else
 941                     last = get(length()-2);
 942             }
 943         }
 944         sym.location = (((Symbol)first).location & 0xffffffff00000000L)
 945                 | (((Symbol)last).location & 0xffffffffL);
 946         /*for(int i=0;i<length();++i) {
 947             Object obj = get(i);
 948             System.out.print(obj.getClass().getSimpleName());
 949             if(obj instanceof Token) {
 950                 Token t = (Token)obj;
 951                 System.out.print("(" + t.text + ")");
 952             }
 953             if(obj instanceof Symbol) {
 954                 Symbol s = (Symbol)obj;
 955                 System.out.print("["+ Locations.beginOf(s.location) + "-" + Locations.endOf(s.location) + "]");
 956             }
 957             System.out.print(" ");
 958         }
 959         System.out.println("-> " + reduced.getClass().getSimpleName() + " " +
 960                 Locations.beginOf(sym.location) + "-" + Locations.endOf(sym.location));*/
 961     }
 962
 963     @Override
 964     protected RuntimeException syntaxError(Token token, String description) {
 965         throw new SCLSyntaxErrorException(token.location, description);
 966     }
 967
 968     @Override
 969     protected Object reduceIdAccessor() {
 970         return new IdAccessor('.', ((Token)get(0)).text);
 971     }
 972
 973     @Override
 974     protected Object reduceStringAccessor() {
 975         return new StringAccessor('.', ((Token)get(1)).text);
 976     }
 977
 978     @Override
 979     protected Object reduceExpAccessor() {
 980         return new ExpressionAccessor('.', (Expression)get(1));
 981     }
 982
 983     @Override
 984     protected Object reduceFieldAccess() {
 985         if(length() == 1)
 986             return get(0);
 987         Expression result = (Expression)get(0);
 988         for(int i=2;i<length();i+=2) {
 989             FieldAccessor accessor = (FieldAccessor)get(i);
 990             accessor.accessSeparator = ((Token)get(i-1)).text.charAt(0);
 991             result = new EFieldAccess(result, accessor);
 992         }
 993         return result;
 994     }
 995
 996     @Override
 997     protected Object reduceQueryBlock() {
 998         if(length() == 2)
 999             return Query.EMPTY_ARRAY;
1000         Query[] queries = new Query[length()/2];
1001         for(int i=0;i<queries.length;++i)
1002             queries[i] = (Query)get(2*i+1);
1003         return queries;
1004     }
1005
1006     @Override
1007     protected Object reduceGuardQuery() {
1008         return new QPreGuard((Expression)get(0));
1009     }
1010
1011     @Override
1012     protected Object reduceEqualsQuery() {
1013         return new QPreEquals((Expression)get(0), (Expression)get(2));
1014     }
1015
1016     @Override
1017     protected Object reduceBindQuery() {
1018         return new QPreBinds((Expression)get(0), (Expression)get(2));
1019     }
1020
1021     @Override
1022     protected Object reduceCompositeQuery() {
1023         Query[] queries = (Query[])get(1);
1024         switch(((Token)get(0)).text.charAt(1)) {
1025         case '&': return new QConjunction(queries);
1026         case '|': return new QDisjunction(queries);
1027         case '!': return new QNegation(new QConjunction(queries));
1028         case '?': return new QAlternative(queries);
1029         default: throw new InternalCompilerError();
1030         }
1031     }
1032
1033     @Override
1034     protected Object reduceRuleStatement() {
1035         return new RuleStatement((Expression)get(0), new QConjunction((Query[])get(2)));
1036     }
1037
1038     @Override
1039     protected Object reduceHashedId() {
1040         return new EVar("#" + ((Token)get(1)).text);
1041     }
1042
1043     @Override
1044     protected Object reduceStringLiteral() {
1045         int expCount = length()/3;
1046         if(expCount == 0)
1047             return new ELiteral(new StringConstant(((Token)get(1)).text));
1048         else {
1049             String[] strings = new String[expCount+1];
1050             Expression[] expressions = new Expression[expCount];
1051             for(int i=0;i<expCount;++i) {
1052                 strings[i] = ((Token)get(i*3+1)).text;
1053                 expressions[i] = (Expression)get(i*3+2);
1054             }
1055             strings[expCount] = ((Token)get(expCount*3+1)).text;
1056             return new EStringLiteral(strings, expressions);
1057         }
1058     }
1059
1060     @Override
1061     protected Object reduceOneCommand() {
1062         return null;
1063     }
1064
1065     @Override
1066     protected Object reduceManyCommands() {
1067         return null;
1068     }
1069
1070     @Override
1071     protected Object reduceStatementCommand() {
1072         // to be extended in subclasses
1073         return null;
1074     }
1075
1076     @Override
1077     protected Object reduceImportCommand() {
1078         // to be extended in subclasses
1079         return null;
1080     }
1081
1082     @Override
1083     protected Object reduceImportValueItem() {
1084         return new EVar(((Token)get(0)).text);
1085     }
1086
1087     @Override
1088     protected Object reduceImportHiding() {
1089         EVar[] values = new EVar[(length()-2)/2];
1090         for(int i=0;i<values.length;++i)
1091             values[i] = (EVar)get(i*2+2);
1092         return new ImportDeclaration.ImportSpec(true, values);
1093     }
1094
1095     @Override
1096     protected Object reduceImportShowing() {
1097         EVar[] values = new EVar[(length()-1)/2];
1098         for(int i=0;i<values.length;++i)
1099             values[i] = (EVar)get(i*2+1);
1100         return new ImportDeclaration.ImportSpec(false, values);
1101     }
1102
1103     @Override
1104     protected Object reduceRuleDeclarations() {
1105         ArrayList<Object> declarations = new ArrayList<Object>(length()/2);
1106         for(int i=1;i<length();i+=2)
1107             declarations.add((Object)get(i));
1108         return declarations;
1109     }
1110
1111     private static final String[] EMPTY_STRING_ARRAY = new String[0];
1112
1113     @SuppressWarnings("unchecked")
1114     @Override
1115     protected Object reduceRuleDefinition() {
1116         String[] extendsNames = EMPTY_STRING_ARRAY;
1117         if(length() >= 6) {
1118             int extendsCount = (length() - 4) / 2;
1119             extendsNames = new String[extendsCount];
1120             for(int i=0;i<extendsCount;++i)
1121                 extendsNames[i] = ((Token)get(3+i*2)).text;
1122         }
1123
1124         DRuleAst rule = new DRuleAst(
1125                 ((Token)get(0)).id == SCLTerminals.ABSTRACT_RULE,
1126                 ((Token)get(1)).text,
1127                 extendsNames);
1128
1129         ArrayList<Object> ruleDeclarations = (ArrayList<Object>)get(length()-1);
1130         ArrayList<Query> section = null;
1131         for(Object decl : ruleDeclarations) {
1132             if(decl instanceof DAnnotationAst) {
1133                 DAnnotationAst annotation = (DAnnotationAst)decl;
1134                 section = rule.getSection(annotation.id.text.substring(1));
1135             }
1136             else if(decl instanceof Query) {
1137                 if(section == null)
1138                     section = rule.getSection("when");
1139                 section.add((Query)decl);
1140             }
1141             else
1142                 throw new InternalCompilerError();
1143         }
1144         return rule;
1145     }
1146
1147     @Override
1148     protected Object reduceQueryRuleDeclaration() {
1149         return get(0);
1150     }
1151
1152     @Override
1153     protected Object reduceMappingRelationDefinition() {
1154         TypeAst[] types = new TypeAst[length()-2];
1155         for(int i=0;i<types.length;++i)
1156             types[i] = (TypeAst)get(i+2);
1157         return new DMappingRelationAst(
1158                 ((Token)get(1)).text,
1159                 types);
1160     }
1161
1162     @Override
1163     protected Object reduceTransformation() {
1164         return new ETransformation(
1165                 ((Token)get(1)).text,
1166                 new QConjunction((Query[])get(3))
1167                 );
1168     }
1169
1170     @SuppressWarnings("unchecked")
1171     @Override
1172     protected Object reduceRelationDefinition() {
1173         return new DRelationAst((Expression)get(0),
1174                 ((ArrayList<Object>)get(2)).toArray());
1175     }
1176
1177     @Override
1178     protected Object reduceRecord() {
1179         FieldAssignment[] fields = new FieldAssignment[length()/2-1];
1180         for(int i=0;i<fields.length;++i)
1181             fields[i] = (FieldAssignment)get(2+i*2);
1182         return new ERecord(new EVar((Token)get(0)), fields);
1183     }
1184
1185     @Override
1186     protected Object reduceField() {
1187         return new FieldAssignment(((Token)get(0)).text, (Expression)get(2));
1188     }
1189
1190     @Override
1191     protected Object reduceFieldShorthand() {
1192         return new FieldAssignment(((Token)get(0)).text, null);
1193     }
1194
1195     @Override
1196     protected Object reduceRecordConstructor() {
1197         int idPos;
1198         for(idPos=0;idPos<length();idPos+=2)
1199             if(((Token)get(idPos)).id == SCLTerminals.ID)
1200                 break;
1201         DAnnotationAst[] annotations = idPos == 0 ? DAnnotationAst.EMPTY_ARRAY : new DAnnotationAst[idPos/2];
1202         for(int i=0;i<idPos/2;++i)
1203             annotations[i] = new DAnnotationAst((Token)get(i*2),
1204                     Arrays.asList((Expression)get(i*2+1)));
1205         TypeAst[] parameters = new TypeAst[(length()-idPos-1)/2];
1206         String[] fieldNames = new String[parameters.length];
1207         for(int i=0;i<parameters.length;++i) {
1208             FieldDescription fieldDesc = (FieldDescription)get(idPos+(i+1)*2);
1209             parameters[i] = fieldDesc.type;
1210             fieldNames[i] = fieldDesc.name;
1211         }
1212         return new ConstructorAst(annotations, (Token)get(idPos), parameters, fieldNames);
1213     }
1214
1215     @Override
1216     protected Object reduceFieldDescription() {
1217         return new FieldDescription(((Token)get(0)).text, (TypeAst)get(2));
1218     }
1219
1220     @Override
1221     protected Object reduceEq() {
1222         return (Expression)get(2);
1223     }
1224
1225     @Override
1226     protected Object reduceEquationBlock() {
1227         if(length() == 0)
1228             return new EEquations(Equation.EMPTY_ARRAY);
1229         Equation[] equations = new Equation[length()/2+1];
1230         for(int i=0;i<equations.length;++i)
1231             equations[i] = (Equation)get(2*i);
1232         return new EEquations(equations);
1233     }
1234
1235     @Override
1236     protected Object reduceGuardEquation() {
1237         return new EqGuard((Expression)get(0));
1238     }
1239
1240     @Override
1241     protected Object reduceBasicEquation() {
1242         return new EqBasic((Expression)get(0), (Expression)get(2));
1243     }
1244
1245     @Override
1246     protected Object reduceViewPattern() {
1247         return new EViewPattern((Expression)get(1), (Expression)get(3));
1248     }
1249
1250     @Override
1251     protected Object reduceCHRStatement() {
1252         return new CHRStatement((ListQualifier[])get(0), (ListQualifier[])get(2));
1253     }
1254
1255     @Override
1256     protected Object reduceConstraintStatement() {
1257         ConstructorAst constructor = (ConstructorAst)get(1);
1258         return new ConstraintStatement(constructor.name, constructor.parameters, constructor.fieldNames, constructor.annotations);
1259     }
1260
1261     @Override
1262     protected Object reduceCHRQuery() {
1263         ListQualifier[] query = new ListQualifier[(length()+1)/2];
1264         for(int i=0;i<query.length;++i)
1265             query[i] = (ListQualifier)get(i*2);
1266         return query;
1267     }
1268
1269     /*
1270     @Override
1271     protected Object reduceWhen() {
1272         return new EWhen(
1273                 new QConjunction((Query[])get(1)),
1274                 (Expression)get(3));
1275     }*/
1276
1277     @Override
1278     protected Object reduceVerboseCHRQuery() {
1279         ListQualifier[] query = new ListQualifier[(length()-1)/2];
1280         for(int i=0;i<query.length;++i)
1281             query[i] = (ListQualifier)get(i*2+1);
1282         return query;
1283     }
1284
1285     @Override
1286     protected Object reduceVerboseCHRStatement() {
1287         return new CHRStatement((ListQualifier[])get(1), (ListQualifier[])get(3));
1288     }
1289
1290     @Override
1291     protected Object reduceDummy() {
1292         throw new UnsupportedOperationException();
1293     }
1294
1295     @Override
1296     protected Object reduceRulesetDefinition() {
1297         Token name = (Token)get(1);
1298         EBlock block = (EBlock)get(3);
1299         return new DRulesetAst(name.text, block);
1300     }
1301
1302     @Override
1303     protected Object reduceLocalInclude() {
1304         Token name = (Token)get(1);
1305         Expression value = (Expression)get(2);
1306         return new IncludeStatement(name, value);
1307     }
1308
1309     /*@Override
1310     protected Object reduceConstraintSpec() {
1311         Expression[] expressions = new Expression[length()/2-1];
1312         for(int i=0;i<expressions.length;++i)
1313             expressions[i] = (Expression)get(2*i+1);
1314         return expressions;
1315     }*/
1316
1317     @Override
1318     protected Object reduceCHRSelect() {
1319         return new EPreCHRSelect((ListQualifier[])get(3), (Expression)get(1));
1320     }
1321
1322 }