| 1 | package uk.co.zonetora.fj.typecheck; |
| 2 | |
| 3 | import java.util.ArrayDeque; |
| 4 | import java.util.ArrayList; |
| 5 | import java.util.Deque; |
| 6 | import java.util.List; |
| 7 | |
| 8 | import uk.co.zonetora.fj.ast.analysis.DepthFirstAdapter; |
| 9 | import uk.co.zonetora.fj.model.ArgumentName; |
| 10 | import uk.co.zonetora.fj.model.Cast; |
| 11 | import uk.co.zonetora.fj.model.ClassName; |
| 12 | import uk.co.zonetora.fj.model.FieldAccess; |
| 13 | import uk.co.zonetora.fj.model.Method; |
| 14 | import uk.co.zonetora.fj.model.MethodInvocation; |
| 15 | import uk.co.zonetora.fj.model.ObjectCreation; |
| 16 | import uk.co.zonetora.fj.model.Term; |
| 17 | import uk.co.zonetora.fj.model.Variable; |
| 18 | import uk.co.zonetora.fj.passes.FJException; |
| 19 | import uk.co.zonetora.fj.util.Arrow; |
| 20 | import uk.co.zonetora.fj.util.Maybe; |
| 21 | import uk.co.zonetora.fj.util.Tuple; |
| 22 | |
| 23 | import static uk.co.zonetora.fj.util.ListUtil.*; |
| 24 | |
| 25 | public class TypeCheck { |
| 26 | |
| 27 | private final Deque<ClassName> typeStack; |
| 28 | private final Deque<Deque<ClassName>> backupStack; |
| 29 | |
| 30 | private final TypeEnvironment typeEnvironment; |
| 31 | private final ClassTable classTable; |
| 32 | private boolean stupidWarningTriggered; |
| 33 | |
| 34 | public TypeCheck(TypeEnvironment typeEnvironment, ClassTable classTable) { |
| 35 | this.typeEnvironment = typeEnvironment; |
| 36 | this.classTable = classTable; |
| 37 | this.typeStack = new ArrayDeque<ClassName>(); |
| 38 | this.backupStack = new ArrayDeque<Deque<ClassName>>(); |
| 39 | |
| 40 | this.stupidWarningTriggered = false; |
| 41 | } |
| 42 | |
| 43 | public ClassName typeCheck(Term code) throws FJException { |
| 44 | |
| 45 | code.visit(this); |
| 46 | |
| 47 | return this.typeStack.pop(); |
| 48 | } |
| 49 | |
| 50 | public void appyRule(Cast cast) { |
| 51 | cast.getCastedTerm().visit(this); |
| 52 | |
| 53 | ClassName castedTermType = this.typeStack.pop(); |
| 54 | |
| 55 | ClassName typeToCastTo = cast.getTypeToCastTo(); |
| 56 | |
| 57 | if(this.classTable.subtype(castedTermType, typeToCastTo)) { |
| 58 | /* ok */ |
| 59 | } else if(this.classTable.subtype(typeToCastTo, castedTermType)) { |
| 60 | /* ok */ |
| 61 | } else { |
| 62 | this.stupidWarningTriggered = true; |
| 63 | } |
| 64 | |
| 65 | this.typeStack.push(typeToCastTo); |
| 66 | |
| 67 | } |
| 68 | |
| 69 | public void appyRule(FieldAccess access) { |
| 70 | |
| 71 | access.getPath().visit(this); |
| 72 | |
| 73 | ClassName pathType = this.typeStack.pop(); |
| 74 | |
| 75 | try { |
| 76 | ClassName fieldType = this.classTable.lookupField(access.getFieldName(), pathType); |
| 77 | |
| 78 | this.typeStack.push(fieldType); |
| 79 | |
| 80 | } catch (FJException e) { |
| 81 | throw new FJTypeCheckException(e); |
| 82 | } |
| 83 | |
| 84 | } |
| 85 | |
| 86 | |
| 87 | public void appyRule(final MethodInvocation invocation) { |
| 88 | invocation.getPath().visit(this); |
| 89 | final ClassName pathType = this.typeStack.pop(); |
| 90 | |
| 91 | Maybe<Method> m = this.classTable.mType(invocation.getMethodName(), pathType); |
| 92 | |
| 93 | m.maybe( |
| 94 | new Runnable() { |
| 95 | public void run() { |
| 96 | throw new FJTypeCheckException("Can't find method in " + pathType); |
| 97 | } |
| 98 | }, |
| 99 | |
| 100 | new Arrow<Method, Runnable> () { |
| 101 | public Runnable run(final Method arg) { |
| 102 | return new Runnable() { |
| 103 | public void run() { |
| 104 | |
| 105 | if(arg.getArguments().size() != invocation.getArguments().size()) { |
| 106 | throw new FJTypeCheckException("Invoking a method with incorrect number of arguments"); |
| 107 | } |
| 108 | |
| 109 | preserveTypeStack(); |
| 110 | |
| 111 | for(Term e : invocation.getArguments() ) { |
| 112 | e.visit(TypeCheck.this); |
| 113 | } |
| 114 | |
| 115 | List<ClassName> argTypes = restoreTypeStack(); |
| 116 | |
| 117 | for(Tuple<ClassName, ClassName> cnPair : zip(argTypes, mapFst(arg.getArguments()))) { |
| 118 | if(!TypeCheck.this.classTable.subtype(cnPair.getX(), cnPair.getY())) { |
| 119 | throw new FJTypeCheckException("Invoking a method with an argument that is not a subtype"); |
| 120 | } |
| 121 | } |
| 122 | |
| 123 | TypeCheck.this.typeStack.push(arg.getReturnType()); |
| 124 | } |
| 125 | }; |
| 126 | } |
| 127 | }).run(); |
| 128 | |
| 129 | } |
| 130 | |
| 131 | public void appyRule(ObjectCreation creation) { |
| 132 | List<ClassName> fieldTypes = mapFst(this.classTable.fields(creation.getNewClassName())); |
| 133 | List<Term> terms = creation.getArgumentTerms(); |
| 134 | |
| 135 | if(fieldTypes.size() != terms.size()) { |
| 136 | throw new FJTypeCheckException("'new' with wrong number of arguments for the constructor"); |
| 137 | } |
| 138 | |
| 139 | preserveTypeStack(); |
| 140 | for(Term t : terms) { |
| 141 | t.visit(this); |
| 142 | } |
| 143 | List<ClassName> argTypes = restoreTypeStack(); |
| 144 | |
| 145 | for(Tuple<ClassName, ClassName> cnPair : zip(argTypes, fieldTypes)) { |
| 146 | if(!this.classTable.subtype(cnPair.getX(), cnPair.getY())) { |
| 147 | throw new FJTypeCheckException("Invoking new with an argument that is not of the right type"); |
| 148 | } |
| 149 | } |
| 150 | |
| 151 | this.typeStack.push(creation.getNewClassName()); |
| 152 | } |
| 153 | |
| 154 | public void appyRule(Variable variable) { |
| 155 | ArgumentName arg = variable.getArgumentName(); |
| 156 | |
| 157 | ClassName cn = this.typeEnvironment.getBinding(arg); |
| 158 | if(cn == null) { |
| 159 | throw new FJTypeCheckException("Variable: " + arg + " is unknown"); |
| 160 | } |
| 161 | |
| 162 | this.typeStack.push(cn); |
| 163 | } |
| 164 | |
| 165 | |
| 166 | private void preserveTypeStack() { |
| 167 | this.backupStack.push(new ArrayDeque<ClassName>(this.typeStack)); |
| 168 | } |
| 169 | |
| 170 | private List<ClassName> restoreTypeStack() { |
| 171 | Deque<ClassName> old = this.backupStack.pop(); |
| 172 | List<ClassName> current = new ArrayList<ClassName>(this.typeStack); |
| 173 | this.typeStack.clear(); |
| 174 | this.typeStack.addAll(old); |
| 175 | return current; |
| 176 | } |
| 177 | |
| 178 | |
| 179 | } |