Beispiel #1
0
  /** @see jaskell.compiler.JaskellVisitor#visit(QualifiedVariable) */
  public Object visit(QualifiedVariable a) {
    Module mod = null;
    Iterator it = a.getPath().iterator();
    while (it.hasNext()) {
      String mname = (String) it.next();
      if (mod != null) mod = (Module) mod.lookup(mname);
      else mod = (Module) Module.getToplevels().get(mname);
    }
    /* module found */
    if (mod != null) {
      Expression def = mod.lookup(a.getName());
      if (def == null) throw new CompilerException("Unknown variable " + a.getName());
      Type t = def.getType();
      if (t == null) t = (Type) def.visit(this);

      /* as it is the case for variable, we assume
       * that a defined symbol may be overloaded (only for primitive types)
       * so we return a type variable and defers choice of
       * symbol to a later stage
       */
      a.setType(t);
      return t;
    }
    throw new CompilerException("Unable to find module needed for variable " + a.getName());
  }
Beispiel #2
0
 /** @see jaskell.compiler.JaskellVisitor#visit(ConstructorPattern) */
 public Object visit(ConstructorPattern a) {
   String cname = a.getConstructor().getName();
   /* retrieve parameter types of constructor */
   ConstructorDefinition ctor = (ConstructorDefinition) a.getConstructor().lookup(cname);
   if (ctor == null) throw new TypeError("Undefined constructor pattern  " + a);
   /* type of data constructed by constructor */
   TypeInstantiator ti = new TypeInstantiator(ctor.getDataType());
   Type rtype = ti.instance();
   Map map = ti.getMap();
   TypeSubstitution ts = new TypeSubstitution(map);
   Iterator ittypes = ctor.getParameters().iterator();
   /* retrieve type of patterns */
   Iterator it = a.getSubPatterns();
   while (it.hasNext()) {
     try {
       Pattern p = (Pattern) it.next();
       Type actual = TypeFactory.freshBinding();
       Type formal = ts.substitute((Type) ittypes.next());
       /* unify both types */
       p.setType(tu.unify(formal, actual, typeVariablesMap));
     } catch (NoSuchElementException nex) {
       throw new TypeError("Wrong number of arguments to pattern " + a);
     }
   }
   a.setType(rtype);
   return a.getType();
 }
Beispiel #3
0
 /**
  * Returns null or throws a TypeError if type cannot be inferred for any definition found.
  * Verifies that main symbol in Main module is typed as <code>IO ()</code>.
  *
  * @see jaskell.compiler.JaskellVisitor#visit(Module)
  */
 public Object visit(Namespace a) {
   // visit definitions
   Iterator it = a.getAllBindings().entrySet().iterator();
   while (it.hasNext()) {
     Map.Entry entry = (Map.Entry) it.next();
     String name = (String) entry.getKey();
     Expression def = (Expression) entry.getValue();
     Type type = (Type) def.visit(this);
     def.setType(type);
     log.finer("TypeChecker => END Visiting " + name);
   }
   log.finer("Substitution map = " + typeVariablesMap);
   return null;
 }
Beispiel #4
0
 /** @see jaskell.compiler.JaskellVisitor#visit(Let) */
 public Object visit(Let a) {
   Type ret = a.getType();
   if (ret != null) return ret;
   // visit definitions
   Iterator it = a.getBindings().entrySet().iterator();
   while (it.hasNext()) {
     Map.Entry entry = (Map.Entry) it.next();
     String name = (String) entry.getKey();
     Expression def = (Expression) entry.getValue();
     log.finer("Visiting " + name);
     def.setType((Type) def.visit(this));
   }
   // visit body
   ret = (Type) a.getBody().visit(this);
   a.setType(ret);
   // return type of body
   return ret;
 }
Beispiel #5
0
  /** @see jaskell.compiler.JaskellVisitor#visit(Alternative) */
  public Object visit(Alternative a) {
    try {
      Type tex = (Type) a.getExpression().visit(this);
      log.finer("In alternative, type of expression " + a.getExpression() + " is " + tex);

      /* set type of bound variable */
      LocalBinding lb = a.getBinding();
      if (lb != null) lb.setType(tex);
      /* visit type of alternatives */
      Iterator it = a.getChoices();
      Type ptype = tex;
      Type btype = null;
      while (it.hasNext()) {
        Map.Entry entry = (Map.Entry) it.next();
        /* checkt type of pattern */
        Type pt = (Type) ((Pattern) entry.getKey()).visit(this);
        if (ptype == null) ptype = pt;
        else ptype = tu.unify(pt, ptype, typeVariablesMap);
        log.finer("In alternative, unifying pattern type " + pt + " to " + ptype);
        Expression expr = (Expression) entry.getValue();
        /* check type of body */
        Type bt = (Type) expr.visit(this);
        //                      /* apply substitution with type variables from pattern */
        //                      TypeSubstitution ts = new TypeSubstitution(typeVariablesMap);
        //                      expr.visit(ts);
        if (btype == null) btype = bt;
        else btype = tu.unify(bt, btype, typeVariablesMap);
        log.finer("In alternative, unifying body type " + bt + " to " + btype);
      }
      /* visit default choice */
      Type deft = (Type) a.getWildcard().visit(this);
      a.setType(btype);
      return btype;
    } catch (TypeError te) {
      if (te.getLineCol() == null) te.setLineCol(a.getTag("source"));
      throw te;
    }
  }
Beispiel #6
0
 /** @see jaskell.compiler.JaskellVisitor#visit(Abstraction) */
 public Object visit(Abstraction a) {
   try {
     Type t = a.getType();
     if (t != null) return subst.substitute(t);
     log.finest("Visiting abstraction : " + a);
     Expression body = a.getBody();
     /* duplicate bindings map to assign types to variables */
     pushContext(a.getBindings());
     /* create fresh type variables as type for each bound
      * variable */
     Iterator it = namesMap.values().iterator();
     LinkedList tl = new LinkedList();
     while (it.hasNext()) {
       LocalBinding name = (LocalBinding) it.next();
       Type vt = TypeFactory.freshBinding();
       name.setType(vt);
       tl.add(vt);
     }
     Type tv = TypeFactory.freshBinding();
     /* create type with all variables for function */
     Type ft = Types.fun(tl, tv);
     log.finer("In abstraction, setting type to " + ft);
     a.setType(ft);
     /* analyze body */
     Type bt = (Type) body.visit(this);
     /* unify return type of function with type of body */
     Type ret = tu.unify(PrimitiveType.getReturnType(ft), bt, typeVariablesMap);
     TyvarSubstitution tys = new TyvarSubstitution(typeVariablesMap);
     tys.visit(a);
     log.finer("Done abstraction, setting type from " + ft + " to " + a.getType());
     popContext();
     return a.getType();
   } catch (TypeError te) {
     if (te.getLineCol() == null) te.setLineCol(a.getTag("source"));
     throw te;
   }
 }
Beispiel #7
0
 /** @see jaskell.compiler.JaskellVisitor#visit(Application) */
 public Object visit(Application a) {
   try {
     /* get type of function */
     Expression fun = a.getFunction();
     /* get type deduced from arguments */
     LinkedList l = new LinkedList();
     Iterator it = a.getArgs().iterator();
     while (it.hasNext()) {
       Expression e = (Expression) it.next();
       l.add((Type) e.visit(this));
     }
     Type vt = TypeFactory.freshBinding();
     Type ft = Types.fun(l, vt);
     log.finer("TypeChecker => In application " + a + ", type is " + ft);
     /* apply substitution on both types */
     ft = subst.substitute(ft);
     /* try to unify function type and constructed types */
     Type t = (Type) fun.visit(this);
     log.finer("In application, function " + fun + " :: " + t);
     t = subst.substitute(t);
     log.finer("In application, trying to unify function type " + t + " with body " + ft);
     /*
      * TODO : problem with unification of constrained types
      */
     TypeApplication uni = (TypeApplication) tu.unify(t, ft, typeVariablesMap);
     /* sets type of functional expression - this allows
      * polymorphic functions to receive several types
      * in the same code */
     // fun.setType(uni);
     /* apply arguments type to compute return type */
     log.finer("Done unify application :" + uni);
     it = PrimitiveType.functionIterator(uni);
     Iterator it2 = l.iterator();
     TypeApplication ut = uni;
     while (it2.hasNext()) {
       /* type of argument */
       Type at = (Type) it2.next();
       ut = (TypeApplication) it.next();
       /* try unification */
       tu.unify(((TypeApplication) ut.getDomain()).getRange(), at, new HashMap(typeVariablesMap));
     }
     ft = subst.substitute(ft);
     fun.setType(ft);
     log.finer("Setting type of functional element [" + fun + "] to :" + ft);
     a.setType(ut.getRange());
     return ut.getRange();
   } catch (TypeError te) {
     if (te.getLineCol() == null) te.setLineCol(a.getTag("source"));
     throw te;
   }
 }