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.chr.ast.CHRAstAtom;
  15 import org.simantics.scl.compiler.elaboration.chr.ast.CHRAstBinds;
  16 import org.simantics.scl.compiler.elaboration.chr.ast.CHRAstConjunction;
  17 import org.simantics.scl.compiler.elaboration.chr.ast.CHRAstEquals;
  18 import org.simantics.scl.compiler.elaboration.chr.ast.CHRAstQuery;
  19 import org.simantics.scl.compiler.elaboration.equation.EqBasic;
  20 import org.simantics.scl.compiler.elaboration.equation.EqGuard;
  21 import org.simantics.scl.compiler.elaboration.equation.Equation;
  22 import org.simantics.scl.compiler.elaboration.expressions.Case;
  23 import org.simantics.scl.compiler.elaboration.expressions.EApply;
  24 import org.simantics.scl.compiler.elaboration.expressions.EAsPattern;
  25 import org.simantics.scl.compiler.elaboration.expressions.EBinary;
  26 import org.simantics.scl.compiler.elaboration.expressions.EBinaryRightSide;
  27 import org.simantics.scl.compiler.elaboration.expressions.EBlock;
  28 import org.simantics.scl.compiler.elaboration.expressions.EConstant;
  29 import org.simantics.scl.compiler.elaboration.expressions.EEnforce;
  30 import org.simantics.scl.compiler.elaboration.expressions.EEquations;
  31 import org.simantics.scl.compiler.elaboration.expressions.EFieldAccess;
  32 import org.simantics.scl.compiler.elaboration.expressions.EIf;
  33 import org.simantics.scl.compiler.elaboration.expressions.EIntegerLiteral;
  34 import org.simantics.scl.compiler.elaboration.expressions.ELambda;
  35 import org.simantics.scl.compiler.elaboration.expressions.EListComprehension;
  36 import org.simantics.scl.compiler.elaboration.expressions.EListLiteral;
  37 import org.simantics.scl.compiler.elaboration.expressions.ELiteral;
  38 import org.simantics.scl.compiler.elaboration.expressions.EMatch;
  39 import org.simantics.scl.compiler.elaboration.expressions.EPreCHRSelect;
  40 import org.simantics.scl.compiler.elaboration.expressions.ERange;
  41 import org.simantics.scl.compiler.elaboration.expressions.ERealLiteral;
  42 import org.simantics.scl.compiler.elaboration.expressions.ERecord;
  43 import org.simantics.scl.compiler.elaboration.expressions.ESelect;
  44 import org.simantics.scl.compiler.elaboration.expressions.ESimpleLambda;
  45 import org.simantics.scl.compiler.elaboration.expressions.EStringLiteral;
  46 import org.simantics.scl.compiler.elaboration.expressions.ETransformation;
  47 import org.simantics.scl.compiler.elaboration.expressions.ETypeAnnotation;
  48 import org.simantics.scl.compiler.elaboration.expressions.EVar;
  49 import org.simantics.scl.compiler.elaboration.expressions.EVariable;
  50 import org.simantics.scl.compiler.elaboration.expressions.EViewPattern;
  51 import org.simantics.scl.compiler.elaboration.expressions.Expression;
  52 import org.simantics.scl.compiler.elaboration.expressions.GuardedExpression;
  53 import org.simantics.scl.compiler.elaboration.expressions.GuardedExpressionGroup;
  54 import org.simantics.scl.compiler.elaboration.expressions.Variable;
  55 import org.simantics.scl.compiler.elaboration.expressions.accessor.ExpressionAccessor;
  56 import org.simantics.scl.compiler.elaboration.expressions.accessor.FieldAccessor;
  57 import org.simantics.scl.compiler.elaboration.expressions.accessor.IdAccessor;
  58 import org.simantics.scl.compiler.elaboration.expressions.accessor.StringAccessor;
  59 import org.simantics.scl.compiler.elaboration.expressions.block.BindStatement;
  60 import org.simantics.scl.compiler.elaboration.expressions.block.BlockType;
  61 import org.simantics.scl.compiler.elaboration.expressions.block.CHRStatement;
  62 import org.simantics.scl.compiler.elaboration.expressions.block.ConstraintStatement;
  63 import org.simantics.scl.compiler.elaboration.expressions.block.GuardStatement;
  64 import org.simantics.scl.compiler.elaboration.expressions.block.IncludeStatement;
  65 import org.simantics.scl.compiler.elaboration.expressions.block.LetStatement;
  66 import org.simantics.scl.compiler.elaboration.expressions.block.RuleStatement;
  67 import org.simantics.scl.compiler.elaboration.expressions.block.Statement;
  68 import org.simantics.scl.compiler.elaboration.expressions.list.ListAssignment;
  69 import org.simantics.scl.compiler.elaboration.expressions.list.ListGenerator;
  70 import org.simantics.scl.compiler.elaboration.expressions.list.ListGuard;
  71 import org.simantics.scl.compiler.elaboration.expressions.list.ListQualifier;
  72 import org.simantics.scl.compiler.elaboration.expressions.list.ListSeq;
  73 import org.simantics.scl.compiler.elaboration.expressions.list.ListThen;
  74 import org.simantics.scl.compiler.elaboration.expressions.records.FieldAssignment;
  75 import org.simantics.scl.compiler.elaboration.java.Builtins;
  76 import org.simantics.scl.compiler.elaboration.query.QAlternative;
  77 import org.simantics.scl.compiler.elaboration.query.QConjunction;
  78 import org.simantics.scl.compiler.elaboration.query.QDisjunction;
  79 import org.simantics.scl.compiler.elaboration.query.QNegation;
  80 import org.simantics.scl.compiler.elaboration.query.Query;
  81 import org.simantics.scl.compiler.elaboration.query.pre.QPreBinds;
  82 import org.simantics.scl.compiler.elaboration.query.pre.QPreEquals;
  83 import org.simantics.scl.compiler.elaboration.query.pre.QPreGuard;
  84 import org.simantics.scl.compiler.errors.Locations;
  85 import org.simantics.scl.compiler.internal.header.ModuleHeader;
  86 import org.simantics.scl.compiler.internal.parsing.Symbol;
  87 import org.simantics.scl.compiler.internal.parsing.Token;
  88 import org.simantics.scl.compiler.internal.parsing.declarations.ConstructorAst;
  89 import org.simantics.scl.compiler.internal.parsing.declarations.DAnnotationAst;
  90 import org.simantics.scl.compiler.internal.parsing.declarations.DClassAst;
  91 import org.simantics.scl.compiler.internal.parsing.declarations.DDataAst;
  92 import org.simantics.scl.compiler.internal.parsing.declarations.DDerivingInstanceAst;
  93 import org.simantics.scl.compiler.internal.parsing.declarations.DDocumentationAst;
  94 import org.simantics.scl.compiler.internal.parsing.declarations.DEffectAst;
  95 import org.simantics.scl.compiler.internal.parsing.declarations.DFixityAst;
  96 import org.simantics.scl.compiler.internal.parsing.declarations.DImportJavaAst;
  97 import org.simantics.scl.compiler.internal.parsing.declarations.DInstanceAst;
  98 import org.simantics.scl.compiler.internal.parsing.declarations.DMappingRelationAst;
  99 import org.simantics.scl.compiler.internal.parsing.declarations.DRelationAst;
 100 import org.simantics.scl.compiler.internal.parsing.declarations.DRuleAst;
 101 import org.simantics.scl.compiler.internal.parsing.declarations.DRulesetAst;
 102 import org.simantics.scl.compiler.internal.parsing.declarations.DTypeAst;
 103 import org.simantics.scl.compiler.internal.parsing.declarations.DValueAst;
 104 import org.simantics.scl.compiler.internal.parsing.declarations.DValueTypeAst;
 105 import org.simantics.scl.compiler.internal.parsing.declarations.DeclarationAst;
 106 import org.simantics.scl.compiler.internal.parsing.declarations.FieldDescription;
 107 import org.simantics.scl.compiler.internal.parsing.declarations.FundepAst;
 108 import org.simantics.scl.compiler.internal.parsing.exceptions.SCLSyntaxErrorException;
 109 import org.simantics.scl.compiler.internal.parsing.types.TApplyAst;
 110 import org.simantics.scl.compiler.internal.parsing.types.TEffectAst;
 111 import org.simantics.scl.compiler.internal.parsing.types.TForAllAst;
 112 import org.simantics.scl.compiler.internal.parsing.types.TFunctionAst;
 113 import org.simantics.scl.compiler.internal.parsing.types.TListAst;
 114 import org.simantics.scl.compiler.internal.parsing.types.TPlainEffectAst;
 115 import org.simantics.scl.compiler.internal.parsing.types.TPredAst;
 116 import org.simantics.scl.compiler.internal.parsing.types.TTupleAst;
 117 import org.simantics.scl.compiler.internal.parsing.types.TVarAst;
 118 import org.simantics.scl.compiler.internal.parsing.types.TypeAst;
 119 import org.simantics.scl.compiler.module.ImportDeclaration;
 120 import org.simantics.scl.compiler.types.Types;
 121
 122
 123 public class SCLParserImpl extends SCLParser {
 124
 125     private final SCLPostLexer lexer;
 126     private SCLParserOptions options;
 127     private CompilationContext context;
 128
 129     public SCLParserImpl(Reader reader) {
 130         this.lexer = new SCLPostLexer(reader);
 131     }
 132
 133     public SCLPostLexer getLexer() {
 134         return lexer;
 135     }
 136
 137     public void setCompilationContext(CompilationContext context) {
 138         this.context = context;
 139         lexer.setCompilationContext(context);
 140     }
 141
 142     public void setParserOptions(SCLParserOptions options) {
 143         this.options = options;
 144         lexer.setParserOptions(options);
 145     }
 146
 147     public boolean isEmpty() throws Exception {
 148         return lexer.peekToken().id == SCLTerminals.EOF;
 149     }
 150
 151     @Override
 152     protected Token nextToken() {
 153         try {
 154             Token token = lexer.nextToken();
 155             /*System.out.println("TOKEN " + token.text + " (" + TERMINAL_NAMES[token.id] + ")" +
 156                     " ["
 157                     + Locations.beginOf(token.location) + ".."
 158                     + Locations.endOf(token.location) + "]");*/
 159             return token;
 160         } catch(Exception e) {
 161             if(e instanceof RuntimeException)
 162                 throw (RuntimeException)e;
 163             else
 164                 throw new RuntimeException(e);
 165         }
 166     }
 167
 168     @Override
 169     protected Object reduceDeclarations() {
 170         ArrayList<DeclarationAst> declarations = new ArrayList<DeclarationAst>(length()/2);
 171         for(int i=1;i<length();i+=2)
 172             declarations.add((DeclarationAst)get(i));
 173         return declarations;
 174     }
 175
 176     @Override
 177     protected Object reduceModule() {
 178         ArrayList<DeclarationAst> declarations = new ArrayList<DeclarationAst>(length()/2+1);
 179         for(int i=0;i<length();i+=2) {
 180             DeclarationAst declaration = (DeclarationAst)get(i);
 181             if(declaration == null)
 182                 continue;
 183             declarations.add(declaration);
 184         }
 185         return declarations;
 186     }
 187
 188     @Override
 189     protected Object reduceModuleHeader() {
 190         FieldAssignment[] fields = new FieldAssignment[length()/2-1];
 191         for(int i=0;i<fields.length;++i)
 192             fields[i] = (FieldAssignment)get(2+i*2);
 193         context.header = ModuleHeader.process(context.errorLog, fields);
 194         return null;
 195     }
 196
 197     @Override
 198     protected Object reduceLocalTypeAnnotation() {
 199         if(length() == 1)
 200             return get(0);
 201         return new ETypeAnnotation((Expression)get(0), (TypeAst)get(2));
 202     }
 203
 204     @Override
 205     protected Object reduceTypeAnnotation() {
 206         EVar[] names = new EVar[length()/2];
 207         for(int i=0;i<names.length;++i)
 208             names[i] = (EVar)get(i*2);
 209         return new DValueTypeAst(
 210                 names,
 211                 (TypeAst)get(length()-1)
 212                 );
 213     }
 214
 215     @Override
 216     protected Object reduceValueDefinition() {
 217         Expression rhs = (Expression)get(1);
 218         return new DValueAst((Expression)get(0), rhs);
 219     }
 220
 221     @Override
 222     protected Object reduceDataDefinition() {
 223         int i=2;
 224         ArrayList<String> parameters = new ArrayList<String>();
 225         while(i < length()) {
 226             Token token = (Token)get(i++);
 227             if(token.id != SCLTerminals.ID)
 228                 break;
 229             parameters.add(token.text);
 230         }
 231         ArrayList<ConstructorAst> constructors = new ArrayList<ConstructorAst>();
 232         for(;i < length();i+=2)
 233             constructors.add((ConstructorAst)get(i));
 234         return new DDataAst(
 235                 ((Token)get(1)).text,
 236                 parameters.toArray(new String[parameters.size()]),
 237                 constructors.toArray(new ConstructorAst[constructors.size()]),
 238                 new String[0]
 239                 );
 240     }
 241
 242     @Override
 243     protected Object reduceTypeDefinition() {
 244         int i=2;
 245         ArrayList<String> parameters = new ArrayList<String>();
 246         while(true) {
 247             Token token = (Token)get(i++);
 248             if(token.id != SCLTerminals.ID)
 249                 break;
 250             parameters.add(token.text);
 251         }
 252         return new DTypeAst(
 253                 ((Token)get(1)).text,
 254                 parameters.toArray(new String[parameters.size()]),
 255                 (TypeAst)get(i)
 256                 );
 257     }
 258
 259     @SuppressWarnings("unchecked")
 260     @Override
 261     protected Object reduceClassDefinition() {
 262         int i=1;
 263         ArrayList<TypeAst> context;
 264         if(get(i) instanceof Token)
 265             context = new ArrayList<TypeAst>(0);
 266         else
 267             context = (ArrayList<TypeAst>)get(i++);
 268         String name = ((Token)get(i++)).text;
 269         ArrayList<String> parameters = new ArrayList<String>();
 270         while(i < length()) {
 271             Token token = (Token)get(i);
 272             if(token.id != SCLTerminals.ID)
 273                 break;
 274             parameters.add(token.text);
 275             ++i;
 276         }
 277         ArrayList<DeclarationAst> declarations = null;
 278         FundepAst[] fundeps = FundepAst.EMPTY_ARRAY;
 279         while(i < length()) {
 280             Token token = (Token)get(i++);
 281             if(token.id == SCLTerminals.WHERE) {
 282                 declarations = (ArrayList<DeclarationAst>)get(i++);
 283             }
 284             else if(token.id == SCLTerminals.BAR) {
 285                 fundeps = (FundepAst[])get(i++);
 286             }
 287             else
 288                 throw new InternalCompilerError();
 289         }
 290         return new DClassAst(context, name,
 291                 parameters.toArray(new String[parameters.size()]),
 292                 fundeps,
 293                 declarations);
 294     }
 295
 296     @Override
 297     protected Object reduceFundep() {
 298         String[] from = new String[length()-2];
 299         for(int i=0;i<from.length;++i)
 300             from[i] = ((Token)get(i)).text;
 301         String to = ((Token)get(length()-1)).text;
 302         return new FundepAst(from, to);
 303     }
 304
 305     @Override
 306     protected Object reduceFundeps() {
 307         FundepAst[] fundeps = new FundepAst[(length()+1)/2];
 308         for(int i=0;i<fundeps.length;++i)
 309             fundeps[i] = (FundepAst)get(i*2);
 310         return fundeps;
 311     }
 312
 313     @SuppressWarnings("unchecked")
 314     @Override
 315     protected Object reduceInstanceDefinition() {
 316         int i=1;
 317         ArrayList<TypeAst> context;
 318         if(get(i) instanceof Token)
 319             context = new ArrayList<TypeAst>(0);
 320         else
 321             context = (ArrayList<TypeAst>)get(i++);
 322         Token nameToken = (Token)get(i++);
 323         EVar name = new EVar(nameToken);
 324         ArrayList<TypeAst> parameters = new ArrayList<TypeAst>();
 325         while(i < length()) {
 326             Object symbol = get(i++);
 327             if(symbol instanceof Token)
 328                 break;
 329             parameters.add((TypeAst)symbol);
 330         }
 331         ArrayList<DeclarationAst> declarations = null;
 332         if(i < length())
 333             declarations = (ArrayList<DeclarationAst>)get(i);
 334         return new DInstanceAst(context, name,
 335                 parameters.toArray(new TypeAst[parameters.size()]),
 336                 declarations);
 337     }
 338
 339     @SuppressWarnings("unchecked")
 340     @Override
 341     protected Object reduceDerivingInstanceDefinition() {
 342         int i=2;
 343         ArrayList<TypeAst> context;
 344         if(get(i) instanceof Token)
 345             context = new ArrayList<TypeAst>(0);
 346         else
 347             context = (ArrayList<TypeAst>)get(i++);
 348         Token nameToken = (Token)get(i++);
 349         EVar name = new EVar(nameToken);
 350         ArrayList<TypeAst> parameters = new ArrayList<TypeAst>();
 351         while(i < length()) {
 352             Object symbol = get(i++);
 353             parameters.add((TypeAst)symbol);
 354         }
 355         return new DDerivingInstanceAst(context, name,
 356                 parameters.toArray(new TypeAst[parameters.size()]));
 357     }
 358
 359     @Override
 360     protected Object reduceDocumentationString() {
 361         return new DDocumentationAst(((Token)get(1)).text);
 362     }
 363
 364     @Override
 365     protected Object reduceAnnotation() {
 366         ArrayList<Expression> parameters = new ArrayList<Expression>(length()-1);
 367         for(int i=1;i<length();++i)
 368             parameters.add((Expression)get(i));
 369         return new DAnnotationAst((Token)get(0), parameters);
 370     }
 371
 372     @Override
 373     protected Object reducePrecedenceDefinition() {
 374         EVar[] symbols = new EVar[length()/2];
 375         for(int i=0;i<symbols.length;++i)
 376             symbols[i] = (EVar)get(2*i + 2);
 377         Associativity associativity;
 378         Token token = (Token)get(0);
 379         if(token.text.equals("infixl"))
 380             associativity = Associativity.LEFT;
 381         else if(token.text.equals("infixr"))
 382             associativity = Associativity.RIGHT;
 383         else
 384             associativity = Associativity.NONASSOC;
 385         return new DFixityAst(
 386                 new Precedence(
 387                         Integer.parseInt(((Token)get(1)).text),
 388                         associativity),
 389                         symbols);
 390     }
 391
 392     @Override
 393     protected Object reduceImport() {
 394         // (AS ID)? importSpec?
 395         int pos = 0;
 396         String importKeyword = ((Token)get(pos++)).text; // (IMPORT | INCLUDE)
 397         ++pos; // BEGIN_STRING
 398         String moduleName = ((Token)get(pos++)).text; // END_STRING
 399         String localName = "";
 400         if(pos < length()) {
 401             Object temp = get(pos);
 402             if(temp instanceof Token) {
 403                 Token token = (Token)temp;
 404                 if(token.id == SCLTerminals.AS) {
 405                     ++pos; // AS
 406                     localName = ((Token)get(pos++)).text; // ID
 407                 }
 408             }
 409         }
 410         ImportDeclaration.ImportSpec spec = ImportDeclaration.DEFAULT_SPEC;
 411         if(pos < length())
 412             spec = (ImportDeclaration.ImportSpec)get(pos++);
 413         return new ImportDeclaration(moduleName, localName,
 414                         importKeyword.equals("include"),
 415                         spec);
 416     }
 417
 418     @Override
 419     protected Object reduceJustImport() {
 420         return get(0);
 421     }
 422
 423     @SuppressWarnings("unchecked")
 424     @Override
 425     protected Object reduceImportJava() {
 426         return new DImportJavaAst(((Token)get(2)).text, (ArrayList<DeclarationAst>)get(4));
 427     }
 428
 429     @Override
 430     protected Object reduceEffectDefinition() {
 431         return new DEffectAst(
 432                 ((Token)get(1)).text,
 433                 ((Token)get(3)).text,
 434                 ((Token)get(5)).text);
 435     }
 436
 437     @Override
 438     protected Object reduceVarId() {
 439         return new EVar((Token)get(0));
 440     }
 441
 442     @Override
 443     protected Object reduceEscapedSymbol() {
 444         return new EVar((Token)get(0));
 445     }
 446
 447     @Override
 448     protected Object reduceTupleTypeConstructor() {
 449         return new TVarAst(Types.tupleConstructor(length()-1).name);
 450     }
 451
 452     @Override
 453     protected Object reduceArrow() {
 454         int i=length()-1;
 455         TypeAst result = (TypeAst)get(i);
 456         i-=2;
 457         while(i >= 0) {
 458             if( ((Token)get(i+1)).text.equals("=>") )
 459                 result = new TPredAst((TypeAst)get(i), result);
 460             else
 461                 result = new TFunctionAst((TypeAst)get(i), result);
 462             i-=2;
 463         }
 464         return result;
 465     }
 466
 467     @Override
 468     protected Object reduceBinary() {
 469         if(length() == 1)
 470             return get(0);
 471         int i=0;
 472         EVar negation = null;
 473         if(get(i) instanceof Token) {
 474             Token token = (Token)get(i++);
 475             negation = new EVar(token);
 476         }
 477         EBinary binary = new EBinary((Expression)get(i++), negation);
 478         while(i < length()) {
 479             EVar operator = (EVar)get(i++);
 480             Expression right = (Expression)get(i++);
 481             binary.rights.add(new EBinaryRightSide(operator, right));
 482         }
 483         return binary;
 484     }
 485
 486     @Override
 487     protected Object reduceSimpleRhs() {
 488         if(length() == 2)
 489             return get(1);
 490         else {
 491             EBlock block = (EBlock)get(3);
 492             Expression expression = (Expression)get(1);
 493             block.addStatement(new GuardStatement(expression));
 494             block.location = Locations.location(Locations.beginOf(expression.location), Locations.endOf(block.location));
 495             return block;
 496         }
 497     }
 498
 499     private GuardedExpressionGroup reduceGuardedExpressionGroup(int length) {
 500         GuardedExpression[] expressions = new GuardedExpression[length];
 501         for(int i=0;i<expressions.length;++i) {
 502             expressions[i] = (GuardedExpression)get(i);
 503         }
 504         return new GuardedExpressionGroup(expressions);
 505     }
 506
 507     @Override
 508     protected Object reduceGuardedRhs() {
 509         int length = length();
 510         if(length > 2 && get(length-2) instanceof Token) {
 511             EBlock block = (EBlock)get(length-1);
 512             block.addStatement(new GuardStatement(reduceGuardedExpressionGroup(length-2)));
 513             block.location = Locations.NO_LOCATION;
 514             return block;
 515         }
 516         else
 517             return reduceGuardedExpressionGroup(length);
 518     }
 519
 520     @Override
 521     protected Object reduceStatements() {
 522         EBlock block = new EBlock();
 523         if(length() > 2)
 524             for(int i=1;i<length();i+=2)
 525                 block.addStatement((Statement)get(i));
 526         return block;
 527     }
 528
 529     @Override
 530     protected Object reduceConstructor() {
 531         int idPos;
 532         for(idPos=0;idPos<length();idPos+=2)
 533             if(((Token)get(idPos)).id == SCLTerminals.ID)
 534                 break;
 535         DAnnotationAst[] annotations = idPos == 0 ? DAnnotationAst.EMPTY_ARRAY : new DAnnotationAst[idPos/2];
 536         for(int i=0;i<idPos/2;++i)
 537             annotations[i] = new DAnnotationAst((Token)get(i*2),
 538                     Arrays.asList((Expression)get(i*2+1)));
 539         TypeAst[] parameters = new TypeAst[length()-idPos-1];
 540         for(int i=0;i<parameters.length;++i)
 541             parameters[i] = (TypeAst)get(i+idPos+1);
 542         return new ConstructorAst(annotations, (Token)get(idPos), parameters, null);
 543     }
 544
 545     @Override
 546     protected Object reduceContext() {
 547         ArrayList<TypeAst> result = new ArrayList<TypeAst>(length()/2-1);
 548         for(int i=1;i<length()-2;i+=2)
 549             result.add((TypeAst)get(i));
 550         return result;
 551     }
 552
 553     @Override
 554     protected Object reduceTypeVar() {
 555         return new TVarAst(((Token)get(0)).text);
 556     }
 557
 558     @Override
 559     protected Object reduceTupleType() {
 560         if(length() == 2)
 561             return new TTupleAst(TypeAst.EMPTY_ARRAY);
 562         if(length() == 3) {
 563             Symbol sym = (Symbol)get(1);
 564             sym.location = Locations.NO_LOCATION;
 565             return sym;
 566         }
 567         int dim = length()/2;
 568         TypeAst[] parameters = new TypeAst[dim];
 569         for(int i=0;i<dim;++i)
 570             parameters[i] = (TypeAst)get(i*2+1);
 571         return new TTupleAst(parameters);
 572     }
 573
 574     @Override
 575     protected Object reduceListType() {
 576         return new TListAst((TypeAst)get(1));
 577     }
 578
 579     @Override
 580     protected Object reduceListTypeConstructor() {
 581         return new TVarAst("[]");
 582     }
 583
 584     @Override
 585     protected Object reduceTupleConstructor() {
 586         return new EVar(Types.tupleConstructor(length()-1).name);
 587     }
 588
 589     @Override
 590     protected Object reduceVar() {
 591         return get(0);
 592     }
 593
 594     @Override
 595     protected Object reduceBlank() {
 596         return new EVar(((Token)get(0)).location, "_");
 597     }
 598
 599     @Override
 600     protected Object reduceInteger() {
 601         return new EIntegerLiteral(((Token)get(0)).text);
 602     }
 603
 604     @Override
 605     protected Object reduceFloat() {
 606         return new ERealLiteral(((Token)get(0)).text);
 607     }
 608
 609     @Override
 610     protected Object reduceString() {
 611         return get(0);
 612     }
 613
 614     @Override
 615     protected Object reduceChar() {
 616         String text = ((Token)get(0)).text;
 617         char c = text.charAt(text.length()-2);
 618         if(text.length() == 4) {
 619             switch(c) {
 620             case 'n': c = '\n'; break;
 621             case 't': c = '\t'; break;
 622             case 'b': c = '\b'; break;
 623             case 'f': c = '\f'; break;
 624             case 'r': c = '\r'; break;
 625             }
 626         }
 627         return new ELiteral(new CharacterConstant(c));
 628     }
 629
 630     @Override
 631     protected Object reduceTuple() {
 632         if(length() == 2)
 633             return new EConstant(Builtins.TUPLE_CONSTRUCTORS[0]);
 634         if(length() == 3) {
 635             Symbol sym = (Symbol)get(1);
 636             sym.location = Locations.NO_LOCATION;
 637             return sym;
 638         }
 639         int dim = length()/2;
 640         Expression[] parameters = new Expression[dim];
 641         for(int i=0;i<dim;++i)
 642             parameters[i] = (Expression)get(i*2+1);
 643         EConstant tupleConstructor = new EConstant(Builtins.TUPLE_CONSTRUCTORS[dim]);
 644         tupleConstructor.location = Locations.location(
 645                 Locations.beginOf(((Token)get(0)).location),
 646                 Locations.endOf(((Token)get(length()-1)).location));
 647         return new EApply(tupleConstructor, parameters);
 648     }
 649
 650     public static Expression rightSection(EVar op, Expression e) {
 651         long loc = Locations.combine(op.location, e.location);
 652         Variable var = new Variable("rightSectionTemp");
 653         return new ESimpleLambda(loc, var,
 654                 new EApply(loc, op, new EVariable(loc, var), e));
 655     }
 656
 657     @Override
 658     protected Object reduceRightSection() {
 659         Variable var = new Variable("rightSectionTemp");
 660         long loc = Locations.combine(((Token)get(0)).location, ((Token)get(length()-1)).location);
 661         EVar symbol = (EVar)get(1);
 662         return new ESimpleLambda(var,
 663                 new EApply(loc, symbol,
 664                         new EVariable(loc, var), (Expression)get(2)));
 665     }
 666
 667     @Override
 668     protected Object reduceLeftSection() {
 669         return new EApply((EVar)get(2), (Expression)get(1));
 670     }
 671
 672     @Override
 673     protected Object reduceListLiteral() {
 674         if(length() == 2)
 675             return new EListLiteral(Expression.EMPTY_ARRAY);
 676         int dim = length()/2;
 677         Expression[] components = new Expression[dim];
 678         for(int i=0;i<dim;++i)
 679             components[i] = (Expression)get(i*2+1);
 680         return new EListLiteral(components);
 681     }
 682
 683     @Override
 684     protected Object reduceRange() {
 685         return new ERange(
 686                 (Expression)get(1),
 687                 (Expression)get(3)
 688                 );
 689     }
 690
 691     @Override
 692     protected Object reduceListComprehension() {
 693         ListQualifier qualifier = (ListQualifier)get(3);
 694         for(int i=5;i<length();i+=2) {
 695             ListQualifier right = (ListQualifier)get(i);
 696             if(right instanceof ListThen) {
 697                 ((ListThen) right).setLeft(qualifier);
 698                 qualifier = right;
 699             }
 700             else
 701                 qualifier = new ListSeq(qualifier, right);
 702         }
 703         return new EListComprehension((Expression)get(1), qualifier);
 704     }
 705
 706     @Override
 707     protected Object reduceAs() {
 708         Token id = (Token)get(0);
 709         return new EAsPattern(new EVar(id.location, id.text), (Expression)get(2));
 710     }
 711
 712     @Override
 713     protected Object reduceGuardedExpEq() {
 714         Expression[] guards = new Expression[length()/2-1];
 715         for(int i=0;i<guards.length;++i)
 716             guards[i] = (Expression)get(i*2+1);
 717         return new GuardedExpression(guards, (Expression)get(length()-1));
 718     }
 719
 720     @Override
 721     protected Object reduceLambda() {
 722         Expression[] patterns = new Expression[length()-3];
 723         for(int i=0;i<patterns.length;++i)
 724             patterns[i] = (Expression)get(i+1);
 725         Case case_ = new Case(patterns, (Expression)get(length()-1));
 726         case_.setLhs(Locations.combine(patterns[0].location, patterns[patterns.length-1].location));
 727         return new ELambda(case_);
 728     }
 729
 730     @Override
 731     protected Object reduceLambdaMatch() {
 732         Case[] cases = new Case[length()/2-1];
 733         for(int i=0;i<cases.length;++i)
 734             cases[i] = (Case)get(i*2+2);
 735         return new ELambda(cases);
 736     }
 737
 738     @Override
 739     protected Object reduceLet() {
 740         EBlock block = (EBlock)get(1);
 741         Expression expression = (Expression)get(3);
 742         block.addStatement(new GuardStatement(expression));
 743         Token letToken = (Token)get(0);
 744         block.location = Locations.location(
 745                 Locations.beginOf(letToken.location),
 746                 Locations.endOf(expression.location));
 747         return block;
 748     }
 749
 750     @Override
 751     protected Object reduceIf() {
 752         return new EIf(
 753                 (Expression)get(1),
 754                 (Expression)get(3),
 755                 length() == 6 ? (Expression)get(5) : null);
 756     }
 757
 758     @Override
 759     protected Object reduceMatch() {
 760         Case[] cases = new Case[length()/2-2];
 761         for(int i=0;i<cases.length;++i)
 762             cases[i] = (Case)get(i*2+4);
 763         return new EMatch((Expression)get(1), cases);
 764     }
 765
 766     @Override
 767     protected Object reduceDo() {
 768         EBlock block = (EBlock)get(1);
 769         Token doToken = (Token)get(0);
 770         switch(doToken.text) {
 771         case "mdo":
 772             block.setBlockType(BlockType.Monad);
 773             break;
 774         case "edo":
 775             block.setBlockType(BlockType.MonadE);
 776             break;
 777         }
 778         block.location = Locations.location(Locations.beginOf(doToken.location), Locations.endOf(block.location));
 779         return block;
 780     }
 781
 782     @Override
 783     protected Object reduceSelect() {
 784         return new ESelect(((Token)get(0)).id, (Expression)get(1), new QConjunction((Query[])get(3)));
 785     }
 786
 787     @Override
 788     protected Object reduceEnforce() {
 789         return new EEnforce(new QConjunction((Query[])get(1)));
 790     }
 791
 792     @Override
 793     protected Object reduceApply() {
 794         if(length() == 1)
 795             return get(0);
 796         Expression[] parameters = new Expression[length()-1];
 797         for(int i=0;i<parameters.length;++i)
 798             parameters[i] = (Expression)get(i+1);
 799         return new EApply((Expression)get(0), parameters);
 800     }
 801
 802     @Override
 803     protected Object reduceSymbol() {
 804         return new EVar(((Token)get(0)).text);
 805     }
 806
 807     @Override
 808     protected Object reduceEscapedId() {
 809         return new EVar(((Token)get(0)).text);
 810     }
 811
 812     @Override
 813     protected Object reduceMinus() {
 814         return new EVar(((Token)get(0)).text);
 815     }
 816
 817     @Override
 818     protected Object reduceLess() {
 819         return new EVar(((Token)get(0)).text);
 820     }
 821
 822     @Override
 823     protected Object reduceGreater() {
 824         return new EVar(((Token)get(0)).text);
 825     }
 826
 827     @Override
 828     protected Object reduceDoubleLess() {
 829         return new EVar(((Token)get(0)).text);
 830     }
 831
 832     @Override
 833     protected Object reduceDoubleGreater() {
 834         return new EVar(((Token)get(0)).text);
 835     }
 836
 837     @Override
 838     protected Object reduceDot() {
 839         return new EVar(((Token)get(0)).text);
 840     }
 841
 842     @Override
 843     protected Object reduceCase() {
 844         return new Case((Expression)get(0), (Expression)get(1));
 845     }
 846
 847     @Override
 848     protected Object reduceGuardQualifier() {
 849         return new ListGuard((Expression)get(0));
 850     }
 851
 852     @Override
 853     protected Object reduceLetQualifier() {
 854         return new ListAssignment((Expression)get(0), (Expression)get(2));
 855     }
 856
 857     @Override
 858     protected Object reduceBindQualifier() {
 859         return new ListGenerator((Expression)get(0), (Expression)get(2));
 860     }
 861
 862     @Override
 863     protected Object reduceThenQualifier() {
 864         return new ListThen((Expression)get(1), length()==4 ? (Expression)get(3) : null);
 865     }
 866
 867     @Override
 868     protected Object reduceGuardStatement() {
 869         return new GuardStatement((Expression)get(0));
 870     }
 871
 872     @Override
 873     protected Object reduceLetStatement() {
 874         return new LetStatement((Expression)get(0), (Expression)get(1));
 875     }
 876
 877     @Override
 878     protected Object reduceBindStatement() {
 879         return new BindStatement((Expression)get(0), (Expression)get(2));
 880     }
 881
 882     @Override
 883     protected Object reduceSimpleCaseRhs() {
 884         return get(1);
 885     }
 886
 887     @Override
 888     protected Object reduceGuardedCaseRhs() {
 889         GuardedExpression[] expressions = new GuardedExpression[length()];
 890         for(int i=0;i<expressions.length;++i)
 891             expressions[i] = (GuardedExpression)get(i);
 892         return new GuardedExpressionGroup(expressions);
 893     }
 894
 895     @Override
 896     protected Object reduceGuardedExpArrow() {
 897         Expression[] guards = new Expression[length()/2-1];
 898         for(int i=0;i<guards.length;++i)
 899             guards[i] = (Expression)get(i*2+1);
 900         return new GuardedExpression(guards, (Expression)get(length()-1));
 901     }
 902
 903     @Override
 904     protected Object reduceEffect() {
 905         ArrayList<TypeAst> effects = new ArrayList<TypeAst>(length()/2-1);
 906         for(int i=1;i<length()-1;i+=2) {
 907             Token token = (Token)get(i);
 908             TVarAst ast = new TVarAst(token.text);
 909             ast.location = token.location;
 910             effects.add(ast);
 911         }
 912         return new TEffectAst(effects, (TypeAst)get(length()-1));
 913     }
 914
 915     @Override
 916     protected Object reduceJustEtype() {
 917         return get(0);
 918     }
 919
 920     @Override
 921     protected Object reduceForAll() {
 922         String[] vars = new String[length()-3];
 923         for(int i=0;i<vars.length;++i)
 924             vars[i] = ((Token)get(i+1)).text;
 925         return new TForAllAst(vars, (TypeAst)get(length()-1));
 926     }
 927
 928     @Override
 929     protected Object reduceApplyType() {
 930         TypeAst[] parameters = new TypeAst[length()-1];
 931         for(int i=0;i<parameters.length;++i)
 932             parameters[i] = (TypeAst)get(i+1);
 933         return new TApplyAst((TypeAst)get(0), parameters);
 934     }
 935
 936     @SuppressWarnings("unchecked")
 937     @Override
 938     protected void postReduce(Object reduced) {
 939         if(!(reduced instanceof Symbol))
 940             return;
 941         Symbol sym = (Symbol)reduced;
 942         if(sym.location != Locations.NO_LOCATION || length() == 0)
 943             return;
 944         Object first = get(0);
 945         if(!(first instanceof Symbol)) {
 946             if(first instanceof List) {
 947                 List<Object> ll = (List<Object>)first;
 948                 first = ll.get(0);
 949             }
 950             else {
 951                 Object[] ll = (Object[])first;
 952                 if(ll.length > 0)
 953                     first = ll[0];
 954                 else
 955                     first = get(1);
 956             }
 957         }
 958         Object last = get(length()-1);
 959         if(!(last instanceof Symbol)) {
 960             if(last instanceof List) {
 961                 List<Object> ll = (List<Object>)last;
 962                 last = ll.get(ll.size()-1);
 963             }
 964             else {
 965                 Object[] ll = (Object[])last;
 966                 if(ll.length > 0)
 967                     last = ll[ll.length-1];
 968                 else
 969                     last = get(length()-2);
 970             }
 971         }
 972         sym.location = (((Symbol)first).location & 0xffffffff00000000L)
 973                 | (((Symbol)last).location & 0xffffffffL);
 974         /*for(int i=0;i<length();++i) {
 975             Object obj = get(i);
 976             System.out.print(obj.getClass().getSimpleName());
 977             if(obj instanceof Token) {
 978                 Token t = (Token)obj;
 979                 System.out.print("(" + t.text + ")");
 980             }
 981             if(obj instanceof Symbol) {
 982                 Symbol s = (Symbol)obj;
 983                 System.out.print("["+ Locations.beginOf(s.location) + "-" + Locations.endOf(s.location) + "]");
 984             }
 985             System.out.print(" ");
 986         }
 987         System.out.println("-> " + reduced.getClass().getSimpleName() + " " +
 988                 Locations.beginOf(sym.location) + "-" + Locations.endOf(sym.location));*/
 989     }
 990
 991     @Override
 992     protected RuntimeException syntaxError(Token token, String description) {
 993         throw new SCLSyntaxErrorException(token.location, description);
 994     }
 995
 996     @Override
 997     protected Object reduceIdAccessor() {
 998         return new IdAccessor('.', ((Token)get(0)).text);
 999     }
1000
1001     @Override
1002     protected Object reduceStringAccessor() {
1003         return new StringAccessor('.', ((Token)get(1)).text);
1004     }
1005
1006     @Override
1007     protected Object reduceExpAccessor() {
1008         return new ExpressionAccessor('.', (Expression)get(1));
1009     }
1010
1011     @Override
1012     protected Object reduceFieldAccess() {
1013         if(length() == 1)
1014             return get(0);
1015         Expression result = (Expression)get(0);
1016         for(int i=2;i<length();i+=2) {
1017             FieldAccessor accessor = (FieldAccessor)get(i);
1018             accessor.accessSeparator = ((Token)get(i-1)).text.charAt(0);
1019             result = new EFieldAccess(result, accessor);
1020         }
1021         return result;
1022     }
1023
1024     @Override
1025     protected Object reduceQueryBlock() {
1026         if(length() == 2)
1027             return Query.EMPTY_ARRAY;
1028         Query[] queries = new Query[length()/2];
1029         for(int i=0;i<queries.length;++i)
1030             queries[i] = (Query)get(2*i+1);
1031         return queries;
1032     }
1033
1034     @Override
1035     protected Object reduceGuardQuery() {
1036         return new QPreGuard((Expression)get(0));
1037     }
1038
1039     @Override
1040     protected Object reduceEqualsQuery() {
1041         return new QPreEquals((Expression)get(0), (Expression)get(2));
1042     }
1043
1044     @Override
1045     protected Object reduceBindQuery() {
1046         return new QPreBinds((Expression)get(0), (Expression)get(2));
1047     }
1048
1049     @Override
1050     protected Object reduceCompositeQuery() {
1051         Query[] queries = (Query[])get(1);
1052         switch(((Token)get(0)).text.charAt(1)) {
1053         case '&': return new QConjunction(queries);
1054         case '|': return new QDisjunction(queries);
1055         case '!': return new QNegation(new QConjunction(queries));
1056         case '?': return new QAlternative(queries);
1057         default: throw new InternalCompilerError();
1058         }
1059     }
1060
1061     @Override
1062     protected Object reduceRuleStatement() {
1063         return new RuleStatement((Expression)get(0), new QConjunction((Query[])get(2)));
1064     }
1065
1066     @Override
1067     protected Object reduceHashedId() {
1068         return new EVar("#" + ((Token)get(1)).text);
1069     }
1070
1071     @Override
1072     protected Object reduceStringLiteral() {
1073         int expCount = length()/3;
1074         if(expCount == 0)
1075             return new ELiteral(new StringConstant(((Token)get(1)).text));
1076         else {
1077             String[] strings = new String[expCount+1];
1078             Expression[] expressions = new Expression[expCount];
1079             for(int i=0;i<expCount;++i) {
1080                 strings[i] = ((Token)get(i*3+1)).text;
1081                 expressions[i] = (Expression)get(i*3+2);
1082             }
1083             strings[expCount] = ((Token)get(expCount*3+1)).text;
1084             return new EStringLiteral(strings, expressions);
1085         }
1086     }
1087
1088     @Override
1089     protected Object reduceOneCommand() {
1090         return null;
1091     }
1092
1093     @Override
1094     protected Object reduceManyCommands() {
1095         return null;
1096     }
1097
1098     @Override
1099     protected Object reduceStatementCommand() {
1100         // to be extended in subclasses
1101         return null;
1102     }
1103
1104     @Override
1105     protected Object reduceImportCommand() {
1106         // to be extended in subclasses
1107         return null;
1108     }
1109
1110     @Override
1111     protected Object reduceImportValueItem() {
1112         return new EVar(((Token)get(0)).text);
1113     }
1114
1115     @Override
1116     protected Object reduceImportHiding() {
1117         EVar[] values = new EVar[(length()-2)/2];
1118         for(int i=0;i<values.length;++i)
1119             values[i] = (EVar)get(i*2+2);
1120         return new ImportDeclaration.ImportSpec(true, values);
1121     }
1122
1123     @Override
1124     protected Object reduceImportShowing() {
1125         EVar[] values = new EVar[(length()-1)/2];
1126         for(int i=0;i<values.length;++i)
1127             values[i] = (EVar)get(i*2+1);
1128         return new ImportDeclaration.ImportSpec(false, values);
1129     }
1130
1131     @Override
1132     protected Object reduceRuleDeclarations() {
1133         ArrayList<Object> declarations = new ArrayList<Object>(length()/2);
1134         for(int i=1;i<length();i+=2)
1135             declarations.add((Object)get(i));
1136         return declarations;
1137     }
1138
1139     private static final String[] EMPTY_STRING_ARRAY = new String[0];
1140
1141     @SuppressWarnings("unchecked")
1142     @Override
1143     protected Object reduceRuleDefinition() {
1144         String[] extendsNames = EMPTY_STRING_ARRAY;
1145         if(length() >= 6) {
1146             int extendsCount = (length() - 4) / 2;
1147             extendsNames = new String[extendsCount];
1148             for(int i=0;i<extendsCount;++i)
1149                 extendsNames[i] = ((Token)get(3+i*2)).text;
1150         }
1151
1152         DRuleAst rule = new DRuleAst(
1153                 ((Token)get(0)).id == SCLTerminals.ABSTRACT_RULE,
1154                 ((Token)get(1)).text,
1155                 extendsNames);
1156
1157         ArrayList<Object> ruleDeclarations = (ArrayList<Object>)get(length()-1);
1158         ArrayList<Query> section = null;
1159         for(Object decl : ruleDeclarations) {
1160             if(decl instanceof DAnnotationAst) {
1161                 DAnnotationAst annotation = (DAnnotationAst)decl;
1162                 section = rule.getSection(annotation.id.text.substring(1));
1163             }
1164             else if(decl instanceof Query) {
1165                 if(section == null)
1166                     section = rule.getSection("when");
1167                 section.add((Query)decl);
1168             }
1169             else
1170                 throw new InternalCompilerError();
1171         }
1172         return rule;
1173     }
1174
1175     @Override
1176     protected Object reduceQueryRuleDeclaration() {
1177         return get(0);
1178     }
1179
1180     @Override
1181     protected Object reduceMappingRelationDefinition() {
1182         TypeAst[] types = new TypeAst[length()-2];
1183         for(int i=0;i<types.length;++i)
1184             types[i] = (TypeAst)get(i+2);
1185         return new DMappingRelationAst(
1186                 ((Token)get(1)).text,
1187                 types);
1188     }
1189
1190     @Override
1191     protected Object reduceTransformation() {
1192         return new ETransformation(
1193                 ((Token)get(1)).text,
1194                 new QConjunction((Query[])get(3))
1195                 );
1196     }
1197
1198     @SuppressWarnings("unchecked")
1199     @Override
1200     protected Object reduceRelationDefinition() {
1201         return new DRelationAst((Expression)get(0),
1202                 ((ArrayList<Object>)get(2)).toArray());
1203     }
1204
1205     @Override
1206     protected Object reduceRecord() {
1207         FieldAssignment[] fields = new FieldAssignment[length()/2-1];
1208         for(int i=0;i<fields.length;++i)
1209             fields[i] = (FieldAssignment)get(2+i*2);
1210         return new ERecord(new EVar((Token)get(0)), fields);
1211     }
1212
1213     @Override
1214     protected Object reduceField() {
1215         return new FieldAssignment(((Token)get(0)).text, (Expression)get(2));
1216     }
1217
1218     @Override
1219     protected Object reduceFieldShorthand() {
1220         return new FieldAssignment(((Token)get(0)).text, null);
1221     }
1222
1223     @Override
1224     protected Object reduceRecordConstructor() {
1225         int idPos;
1226         for(idPos=0;idPos<length();idPos+=2)
1227             if(((Token)get(idPos)).id == SCLTerminals.ID)
1228                 break;
1229         DAnnotationAst[] annotations = idPos == 0 ? DAnnotationAst.EMPTY_ARRAY : new DAnnotationAst[idPos/2];
1230         for(int i=0;i<idPos/2;++i)
1231             annotations[i] = new DAnnotationAst((Token)get(i*2),
1232                     Arrays.asList((Expression)get(i*2+1)));
1233         TypeAst[] parameters = new TypeAst[(length()-idPos-1)/2];
1234         String[] fieldNames = new String[parameters.length];
1235         for(int i=0;i<parameters.length;++i) {
1236             FieldDescription fieldDesc = (FieldDescription)get(idPos+(i+1)*2);
1237             parameters[i] = fieldDesc.type;
1238             fieldNames[i] = fieldDesc.name;
1239         }
1240         return new ConstructorAst(annotations, (Token)get(idPos), parameters, fieldNames);
1241     }
1242
1243     @Override
1244     protected Object reduceFieldDescription() {
1245         return new FieldDescription(((Token)get(0)).text, (TypeAst)get(2));
1246     }
1247
1248     @Override
1249     protected Object reduceEq() {
1250         return (Expression)get(2);
1251     }
1252
1253     @Override
1254     protected Object reduceEquationBlock() {
1255         if(length() == 0)
1256             return new EEquations(Equation.EMPTY_ARRAY);
1257         Equation[] equations = new Equation[length()/2+1];
1258         for(int i=0;i<equations.length;++i)
1259             equations[i] = (Equation)get(2*i);
1260         return new EEquations(equations);
1261     }
1262
1263     @Override
1264     protected Object reduceGuardEquation() {
1265         return new EqGuard((Expression)get(0));
1266     }
1267
1268     @Override
1269     protected Object reduceBasicEquation() {
1270         return new EqBasic((Expression)get(0), (Expression)get(2));
1271     }
1272
1273     @Override
1274     protected Object reduceViewPattern() {
1275         return new EViewPattern((Expression)get(1), (Expression)get(3));
1276     }
1277
1278     @Override
1279     protected Object reduceConstraintStatement() {
1280         ConstructorAst constructor = (ConstructorAst)get(1);
1281         return new ConstraintStatement(constructor.name, constructor.parameters, constructor.fieldNames, constructor.annotations);
1282     }
1283
1284     /*
1285     @Override
1286     protected Object reduceWhen() {
1287         return new EWhen(
1288                 new QConjunction((Query[])get(1)),
1289                 (Expression)get(3));
1290     }*/
1291
1292     @Override
1293     protected Object reduceDummy() {
1294         throw new UnsupportedOperationException();
1295     }
1296
1297     @Override
1298     protected Object reduceRulesetDefinition() {
1299         Token name = (Token)get(1);
1300         EBlock block = (EBlock)get(3);
1301         return new DRulesetAst(name.text, block);
1302     }
1303
1304     @Override
1305     protected Object reduceLocalInclude() {
1306         Token name = (Token)get(1);
1307         Expression value = (Expression)get(2);
1308         return new IncludeStatement(name, value);
1309     }
1310
1311     /*@Override
1312     protected Object reduceConstraintSpec() {
1313         Expression[] expressions = new Expression[length()/2-1];
1314         for(int i=0;i<expressions.length;++i)
1315             expressions[i] = (Expression)get(2*i+1);
1316         return expressions;
1317     }*/
1318
1319     @Override
1320     protected Object reduceCHRSelect() {
1321         return new EPreCHRSelect((CHRAstQuery)get(3), (Expression)get(1));
1322     }
1323
1324     @Override
1325     protected Object reduceCHRAtom() {
1326         return CHRAstAtom.atom((Expression)get(0));
1327     }
1328
1329     @Override
1330     protected Object reduceCHREquals() {
1331         return new CHRAstEquals((Expression)get(0), (Expression)get(2));
1332     }
1333
1334     @Override
1335     protected Object reduceCHRBinds() {
1336         return new CHRAstBinds((Expression)get(0), (Expression)get(2));
1337     }
1338
1339     @Override
1340     protected Object reduceCHRConjunction() {
1341         CHRAstQuery[] conjuncts = new CHRAstQuery[(length()+1)/2];
1342         for(int i=0;i<conjuncts.length;++i)
1343             conjuncts[i] = (CHRAstQuery)get(i*2);
1344         return CHRAstConjunction.conjunction(conjuncts);
1345     }
1346
1347     @Override
1348     protected Object reduceVerboseCHRConjunction() {
1349         CHRAstQuery[] conjuncts = new CHRAstQuery[(length()-1)/2];
1350         for(int i=0;i<conjuncts.length;++i)
1351             conjuncts[i] = (CHRAstQuery)get(i*2+1);
1352         return CHRAstConjunction.conjunction(conjuncts);
1353     }
1354
1355     @Override
1356     protected Object reduceVerboseCHRStatement() {
1357         return new CHRStatement((CHRAstQuery)get(1), (CHRAstQuery)get(3));
1358     }
1359
1360     @Override
1361     protected Object reduceCHRStatement() {
1362         return new CHRStatement((CHRAstQuery)get(0), (CHRAstQuery)get(2));
1363     }
1364
1365     @Override
1366     protected Object reduceWildcard() {
1367         return new FieldAssignment(FieldAssignment.WILDCARD, null);
1368     }
1369
1370     @Override
1371     protected Object reducePlainEffect() {
1372         ArrayList<TypeAst> effects = new ArrayList<TypeAst>(length()/2);
1373         for(int i=1;i<length();i+=2) {
1374             Token token = (Token)get(i);
1375             TVarAst ast = new TVarAst(token.text);
1376             ast.location = token.location;
1377             effects.add(ast);
1378         }
1379         return new TPlainEffectAst(effects);
1380     }
1381
1382 }