Rearrange directory structure

1 files changed, 1097 insertions, 0 deletions

diff --git a/typecheck/TypeCheckSimp.java b/typecheck/TypeCheckSimp.java
new file mode 100644
index 0000000..99fa187
--- /dev/null
+++ b/typecheck/TypeCheckSimp.java
@@ -0,0 +1,1097 @@
+package typecheck;
+
+import syntaxtree.*;
+import visitor.*;
+import st.*;
+import misc.*;
+import java.util.*;
+
+/**
+ * Provides default methods which visit each node in the tree in depth-first
+ * order.  Your visitors may extend this class.
+ */
+public class TypeCheckSimp extends GJDepthFirst<TypeInstance,SymbolTable> {
+
+    private int offset;
+
+    private void printNode(Node n, SymbolTable symt, boolean enter, TypeEnum consensus) {
+        String str = "";
+        for (int i=0; i < this.offset; ++i)
+            str += ".";
+        if (enter)
+            str += "Visiting ";
+        else
+            str += "Leaving ";
+        str += "n.getClass().getSimpleName()";
+        if (!enter) {
+            if (consensus == TypeEnum.ERROR)
+                str += " did not type check.";
+            else
+                str += String.format(" found type %s", consensus);
+        }
+        MinimalLogger.info(str);
+    }
+
+    public TypeInstance visit(NodeList n, SymbolTable symt) {
+        ++this.offset;
+        this.printNode(n, symt, true, null);
+
+        TypeInstance ret = new TypeInstance(null, TypeEnum.CHECK);
+        int _count=0;
+        for ( Enumeration<Node> e = n.elements(); e.hasMoreElements(); ) {
+            TypeInstance node = e.nextElement().accept(this,symt);
+            e.nextElement().accept(this,symt);
+            if (node.getType() == TypeEnum.ERROR)
+                ret = node;
+            _count++;
+        }
+
+        this.printNode(n, symt, false, ret.getType());
+        --this.offset;
+        return ret;
+    }
+
+    public TypeInstance visit(NodeListOptional n, SymbolTable symt) {
+        ++this.offset;
+        this.printNode(n, symt, true, null);
+
+        TypeInstance ret;
+        if ( n.present() ) {
+            ret = new TypeInstance(null, TypeEnum.CHECK);
+            int _count=0;
+            for ( Enumeration<Node> e = n.elements(); e.hasMoreElements(); ) {
+                TypeInstance node = e.nextElement().accept(this,symt);
+                if (node.getType() == TypeEnum.ERROR)
+                    ret = node;
+                _count++;
+            }
+        }
+        else
+            ret = new TypeInstance(null, TypeEnum.CHECK);
+
+        this.printNode(n, symt, false, ret.getType());
+        --this.offset;
+        return ret;
+    }
+
+    // FIXME
+    public TypeInstance visit(NodeOptional n, SymbolTable symt) {
+        ++this.offset;
+        this.printNode(n, symt, true, null);
+
+        TypeInstance ret;
+
+        if ( n.present() )
+            ret = n.node.accept(this,symt);
+        else
+            ret = new TypeInstance(null, TypeEnum.CHECK);
+
+        this.printNode(n, symt, false, ret.getType());
+        --this.offset;
+        return ret;
+    }
+
+    public TypeInstance visit(NodeSequence n, SymbolTable symt) {
+        ++this.offset;
+        this.printNode(n, symt, true, null);
+
+        TypeInstance ret = new TypeInstance(null, TypeEnum.CHECK);
+        int _count=0;
+        for ( Enumeration<Node> e = n.elements(); e.hasMoreElements(); ) {
+            TypeInstance node = e.nextElement().accept(this,symt);
+            if (node.getType() == TypeEnum.ERROR)
+                ret = node;
+            _count++;
+        }
+
+        this.printNode(n, symt, false, ret.getType());
+        --this.offset;
+        return ret;
+    }
+
+    public TypeInstance visit(NodeToken n, SymbolTable symt) {
+        // A fixed string token. '⌣'
+        String str = "";
+        for (int i=0; i < this.offset; ++i)
+            str += ".";
+        MinimalLogger.info(String.format("%sLeaving %s => %s",
+                                         str,
+                                         n.getClass().getSimpleName(),
+                                         n.toString()));
+        return null;
+    }
+
+    //
+    // User-generated visitor methods below
+    //
+
+    /**
+     * f0 -> MainClass()
+     * f1 -> ( TypeDeclaration() )*
+     * f2 -> <EOF>
+     */
+    public TypeInstance visit(Goal n, SymbolTable symt) {
+        ++this.offset;
+        this.printNode(n, symt, true, null);
+
+        TypeInstance ret = n.f0.accept(this, symt);
+        n.f1.accept(this, symt);
+        n.f2.accept(this, symt);
+
+        this.printNode(n, symt, false, ret.getType());
+        --this.offset;
+        return ret;
+    }
+
+    /**
+     * f0 -> "class"
+     * f1 -> Identifier()
+     * f2 -> "{"
+     * f3 -> "public"
+     * f4 -> "static"
+     * f5 -> "void"
+     * f6 -> "main"
+     * f7 -> "("
+     * f8 -> "String"
+     * f9 -> "["
+     * f10 -> "]"
+     * f11 -> Identifier()
+     * f12 -> ")"
+     * f13 -> "{"
+     * f14 -> ( VarDeclaration() )*
+     * f15 -> ( Statement() )*
+     * f16 -> "}"
+     * f17 -> "}"
+     */
+    public TypeInstance visit(MainClass n, SymbolTable symt) {
+        ++this.offset;
+        this.printNode(n, symt, true, null);
+
+        n.f0.accept(this, symt);
+        TypeInstance name = n.f1.accept(this, symt);
+        n.f2.accept(this, symt);
+        n.f3.accept(this, symt);
+        n.f4.accept(this, symt);
+        n.f5.accept(this, symt);
+        n.f6.accept(this, symt);
+        n.f7.accept(this, symt);
+        n.f8.accept(this, symt);
+        n.f9.accept(this, symt);
+        n.f10.accept(this, symt);
+        // TypeInstance args = n.f11.accept(this, symt);
+        n.f12.accept(this, symt);
+        n.f13.accept(this, symt);
+        TypeInstance var_dec = n.f14.accept(this, symt);
+        TypeInstance stmt = n.f15.accept(this, symt);
+        n.f16.accept(this, symt);
+        n.f17.accept(this, symt);
+
+        this.printNode(n, symt, false, stmt.getType());
+        --this.offset;
+        return stmt;
+    }
+
+    /**
+     * f0 -> ClassDeclaration()
+     *     | ClassExtendsDeclaration()
+     */
+    public TypeInstance visit(TypeDeclaration n, SymbolTable symt) {
+        ++this.offset;
+        this.printNode(n, symt, true, null);
+
+        TypeInstance ret = n.f0.accept(this, symt);
+
+        this.printNode(n, symt, false, ret.getType());
+        --this.offset;
+        return ret;
+    }
+
+    /**
+     * f0 -> "class"
+     * f1 -> Identifier()
+     * f2 -> "{"
+     * f3 -> ( VarDeclaration() )*
+     * f4 -> ( MethodDeclaration() )*
+     * f5 -> "}"
+     */
+    public TypeInstance visit(ClassDeclaration n, SymbolTable symt) {
+        ++this.offset;
+        this.printNode(n, symt, true, null);
+
+        n.f0.accept(this, symt);
+        TypeInstance id = n.f1.accept(this, symt);
+        n.f2.accept(this, symt);
+        TypeInstance vars = n.f3.accept(this, symt);
+        TypeInstance mtds = n.f4.accept(this, symt);
+        n.f5.accept(this, symt);
+        TypeInstance ret = (vars.hasChecked() &&
+                            mtds.hasChecked()) ?
+            new TypeInstance(null, TypeEnum.CHECK) :
+            new TypeInstance(null, TypeEnum.ERROR);
+
+        this.printNode(n, symt, false, ret.getType());
+        --this.offset;
+        return ret;
+    }
+
+    /**
+     * f0 -> "class"
+     * f1 -> Identifier()
+     * f2 -> "extends"
+     * f3 -> Identifier()
+     * f4 -> "{"
+     * f5 -> ( VarDeclaration() )*
+     * f6 -> ( MethodDeclaration() )*
+     * f7 -> "}"
+     */
+    public TypeInstance visit(ClassExtendsDeclaration n, SymbolTable symt) {
+        ++this.offset;
+        this.printNode(n, symt, true, null);
+
+        n.f0.accept(this, symt);
+        TypeInstance id = n.f1.accept(this, symt);
+        n.f2.accept(this, symt);
+        TypeInstance ext = n.f3.accept(this, symt);
+        n.f4.accept(this, symt);
+        TypeInstance vars = n.f5.accept(this, symt);
+        TypeInstance mehs = n.f6.accept(this, symt);
+        n.f7.accept(this, symt);
+        TypeInstance ret = (id.getType() == TypeEnum.classname &&
+                            vars.hasChecked() &&
+                            mehs.hasChecked()) ?
+            new TypeInstance(null, TypeEnum.CHECK) :
+            new TypeInstance(null, TypeEnum.ERROR);
+
+        this.printNode(n, symt, false, ret.getType());
+        --this.offset;
+        return ret;
+    }
+
+    // FIXME (this may be ST-only)
+    /**
+     * f0 -> Type()
+     * f1 -> Identifier()
+     * f2 -> ";"
+     */
+    public TypeInstance visit(VarDeclaration n, SymbolTable symt) {
+        ++this.offset;
+        this.printNode(n, symt, true, null);
+
+        TypeInstance ret = n.f0.accept(this, symt);
+        n.f1.accept(this, symt);
+        n.f2.accept(this, symt);
+
+        this.printNode(n, symt, false, ret.getType());
+        --this.offset;
+        return ret;
+    }
+
+    // FIXME
+    /**
+     * [7.5]: Parameters identifiers are distinct, local vars are distinct,
+     * (vars in scope?), all statements type check
+     *
+     * f0 -> "public"
+     * f1 -> Type()
+     * f2 -> Identifier()
+     * f3 -> "("
+     * f4 -> ( FormalParameterList() )?
+     * f5 -> ")"
+     * f6 -> "{"
+     * f7 -> ( VarDeclaration() )*
+     * f8 -> ( Statement() )*
+     * f9 -> "return"
+     * f10 -> Expression()
+     * f11 -> ";"
+     * f12 -> "}"
+     */
+    public TypeInstance visit(MethodDeclaration n, SymbolTable symt) {
+        ++this.offset;
+        this.printNode(n, symt, true, null);
+
+        MethodInstance self = symt.getMethod(n.f2.f0.tokenImage);
+        n.f0.accept(this, symt);
+        TypeInstance ret_type = n.f1.accept(this, symt);
+        n.f2.accept(this, symt);
+        n.f3.accept(this, symt);
+        n.f4.accept(this, symt);
+        n.f5.accept(this, symt);
+        n.f6.accept(this, symt);
+        n.f7.accept(this, symt);
+        TypeInstance stmt = n.f8.accept(this, symt);
+        n.f9.accept(this, symt);
+        TypeInstance rtrn = n.f10.accept(this, symt);
+        n.f11.accept(this, symt);
+        n.f12.accept(this, symt);
+        TypeInstance ret = (self.getReturn() == rtrn.getType() && // FIXME I am checking that the rtrn matches the method's declared return type. Is this in the document?
+                            stmt.hasChecked()) ?
+            new TypeInstance(null, TypeEnum.CHECK) :
+            new TypeInstance(null, TypeEnum.ERROR);
+
+        this.printNode(n, symt, false, ret.getType());
+        --this.offset;
+        return ret;
+    }
+
+    /**
+     * f0 -> FormalParameter()
+     * f1 -> ( FormalParameterRest() )*
+     */
+    public TypeInstance visit(FormalParameterList n, SymbolTable symt) {
+        ++this.offset;
+        this.printNode(n, symt, true, null);
+
+        TypeInstance _ret=null;
+        TypeInstance para1 = n.f0.accept(this, symt);
+        TypeInstance parar = n.f1.accept(this, symt);
+        TypeInstance ret = (para1.hasChecked() &&
+                            parar.hasChecked()) ?
+            new TypeInstance(null, TypeEnum.CHECK) :
+            new TypeInstance(null, TypeEnum.ERROR);
+
+        this.printNode(n, symt, false, ret.getType());
+        --this.offset;
+        return ret;
+    }
+
+    /**
+     * f0 -> Type()
+     * f1 -> Identifier()
+     */
+    public TypeInstance visit(FormalParameter n, SymbolTable symt) {
+        ++this.offset;
+        this.printNode(n, symt, true, null);
+
+        TypeInstance ret = n.f0.accept(this, symt);
+        n.f1.accept(this, symt);
+
+        this.printNode(n, symt, false, ret.getType());
+        --this.offset;
+        return ret;
+    }
+
+    /**
+     * f0 -> ","
+     * f1 -> FormalParameter()
+     */
+    public TypeInstance visit(FormalParameterRest n, SymbolTable symt) {
+        ++this.offset;
+        this.printNode(n, symt, true, null);
+
+        n.f0.accept(this, symt);
+        TypeInstance ret = n.f1.accept(this, symt);
+
+        this.printNode(n, symt, false, ret.getType());
+        --this.offset;
+        return ret;
+    }
+
+    /**
+     * f0 -> ArrayType()
+     *     | BooleanType()
+     *     | IntegerType()
+     *     | Identifier()
+     */
+    public TypeInstance visit(Type n, SymbolTable symt) {
+        ++this.offset;
+        this.printNode(n, symt, true, null);
+
+        TypeInstance ret = n.f0.accept(this, symt);
+
+        this.printNode(n, symt, false, ret.getType());
+        --this.offset;
+        return ret;
+    }
+
+    /**
+     * f0 -> "int"
+     * f1 -> "["
+     * f2 -> "]"
+     */
+    public TypeInstance visit(ArrayType n, SymbolTable symt) {
+        ++this.offset;
+        this.printNode(n, symt, true, null);
+
+        TypeInstance ret = new TypeInstance(null, TypeEnum.intarray);
+
+        this.printNode(n, symt, false, ret.getType());
+        --this.offset;
+        return ret;
+    }
+
+    /**
+     * f0 -> "boolean"
+     */
+    public TypeInstance visit(BooleanType n, SymbolTable symt) {
+        ++this.offset;
+        this.printNode(n, symt, true, null);
+
+        TypeInstance ret = new TypeInstance(null, TypeEnum.bool);
+
+        this.printNode(n, symt, false, ret.getType());
+        --this.offset;
+        return ret;
+    }
+
+    /**
+     * f0 -> "int"
+     */
+    public TypeInstance visit(IntegerType n, SymbolTable symt) {
+        ++this.offset;
+        this.printNode(n, symt, true, null);
+
+        TypeInstance ret = new TypeInstance(null, TypeEnum.integer);
+
+        this.printNode(n, symt, false, ret.getType());
+        --this.offset;
+        return ret;
+    }
+
+    /**
+     * f0 -> Block()
+     *     | AssignmentStatement()
+     *     | ArrayAssignmentStatement()
+     *     | IfStatement()
+     *     | WhileStatement()
+     *     | PrintStatement()
+     */
+    public TypeInstance visit(Statement n, SymbolTable symt) {
+        ++this.offset;
+        this.printNode(n, symt, true, null);
+
+        TypeInstance ret =      n.f0.accept(this, symt);
+
+        this.printNode(n, symt, false, ret.getType());
+        --this.offset;
+        return ret;
+    }
+
+    /**
+     * f0 -> "{"
+     * f1 -> ( Statement() )*
+     * f2 -> "}"
+     */
+    public TypeInstance visit(Block n, SymbolTable symt) {
+        ++this.offset;
+        this.printNode(n, symt, true, null);
+
+        n.f0.accept(this, symt);
+        TypeInstance ret = n.f1.accept(this, symt);
+        n.f2.accept(this, symt);
+
+        this.printNode(n, symt, false, ret.getType());
+        --this.offset;
+        return ret;
+    }
+
+    // FIXME FIXME FIXME
+    // Given we only have a few types, what is a subtype of what?
+    /**
+     * [23]: Expression is a subtype of identifier, and e typechecks*
+     *
+     * f0 -> Identifier()
+     * f1 -> "="
+     * f2 -> Expression()
+     * f3 -> ";"
+     */
+    public TypeInstance visit(AssignmentStatement n, SymbolTable symt) {
+        ++this.offset;
+        this.printNode(n, symt, true, null);
+
+        TypeInstance lhs = n.f0.accept(this, symt);
+        n.f1.accept(this, symt);
+        TypeInstance rhs = n.f2.accept(this, symt);
+        n.f3.accept(this, symt);
+        TypeInstance ret = (lhs.sameType(rhs)) ?
+            new TypeInstance(null, TypeEnum.CHECK) :
+            new TypeInstance(null, TypeEnum.ERROR);
+
+        this.printNode(n, symt, false, ret.getType());
+        --this.offset;
+        return ret;
+    }
+
+    // FIXME (this may be done)
+    /**
+     * [24]: Identifier is an integer array, expressions are both integers
+     *
+     * f0 -> Identifier()
+     * f1 -> "["
+     * f2 -> Expression()
+     * f3 -> "]"
+     * f4 -> "="
+     * f5 -> Expression()
+     * f6 -> ";"
+     */
+    public TypeInstance visit(ArrayAssignmentStatement n, SymbolTable symt) {
+        ++this.offset;
+        this.printNode(n, symt, true, null);
+
+        TypeInstance id = n.f0.accept(this, symt);
+        n.f1.accept(this, symt);
+        TypeInstance index = n.f2.accept(this, symt);
+        n.f3.accept(this, symt);
+        n.f4.accept(this, symt);
+        TypeInstance value = n.f5.accept(this, symt);
+        n.f6.accept(this, symt);
+        TypeInstance ret =      (id.getType() == TypeEnum.intarray &&
+                                 index.getType() == TypeEnum.integer &&
+                                 value.getType() == TypeEnum.integer) ?
+            new TypeInstance(null, TypeEnum.CHECK) :
+            new TypeInstance(null, TypeEnum.ERROR);
+
+        this.printNode(n, symt, false, ret.getType());
+        --this.offset;
+        return ret;
+    }
+
+    /**
+     * DONE [25]: Expression is a bool, both statements type-check
+     *
+     * f0 -> "if"
+     * f1 -> "("
+     * f2 -> Expression()
+     * f3 -> ")"
+     * f4 -> Statement()
+     * f5 -> "else"
+     * f6 -> Statement()
+     */
+    public TypeInstance visit(IfStatement n, SymbolTable symt) {
+        ++this.offset;
+        this.printNode(n, symt, true, null);
+
+        n.f0.accept(this, symt);
+        n.f1.accept(this, symt);
+        TypeInstance expr = n.f2.accept(this, symt);
+        n.f3.accept(this, symt);
+        TypeInstance stmt1 = n.f4.accept(this, symt);
+        n.f5.accept(this, symt);
+        TypeInstance stmt2 = n.f6.accept(this, symt);
+        TypeInstance ret = (expr.getType() == TypeEnum.bool &&
+                            stmt1.getType() == stmt2.getType() &&
+                            stmt1.hasChecked()) ?
+            new TypeInstance(null, TypeEnum.CHECK) :
+            new TypeInstance(null, TypeEnum.ERROR);
+
+        this.printNode(n, symt, false, ret.getType());
+        --this.offset;
+        return ret;
+
+    }
+
+    /**
+     * DONE [26]: Expression is a bool, statement type-checks
+     *
+     * f0 -> "while"
+     * f1 -> "("
+     * f2 -> Expression()
+     * f3 -> ")"
+     * f4 -> Statement()
+     */
+    public TypeInstance visit(WhileStatement n, SymbolTable symt) {
+        ++this.offset;
+        this.printNode(n, symt, true, null);
+
+        n.f0.accept(this, symt);
+        n.f1.accept(this, symt);
+        TypeInstance expr = n.f2.accept(this, symt);
+        n.f3.accept(this, symt);
+        TypeInstance stmt = n.f4.accept(this, symt);
+        TypeInstance ret = (expr.getType() == TypeEnum.bool &&
+                            stmt.hasChecked()) ?
+            new TypeInstance(null, TypeEnum.CHECK) :
+            new TypeInstance(null, TypeEnum.ERROR);
+
+        this.printNode(n, symt, false, ret.getType());
+        --this.offset;
+        return ret;
+    }
+
+    /**
+     * DONE [27]: Expression is an integer
+     *
+     * f0 -> "System.out.println"
+     * f1 -> "("
+     * f2 -> Expression()
+     * f3 -> ")"
+     * f4 -> ";"
+     */
+    public TypeInstance visit(PrintStatement n, SymbolTable symt) {
+        ++this.offset;
+        this.printNode(n, symt, true, null);
+
+        n.f0.accept(this, symt);
+        n.f1.accept(this, symt);
+        TypeInstance ret = n.f2.accept(this, symt);
+        n.f3.accept(this, symt);
+        n.f4.accept(this, symt);
+        ret = (ret.getType() == TypeEnum.integer) ?
+            new TypeInstance(null, TypeEnum.CHECK) :
+            new TypeInstance(null, TypeEnum.ERROR);
+
+        this.printNode(n, symt, false, ret.getType());
+        --this.offset;
+        return ret;
+    }
+
+    /**
+     * f0 -> AndExpression()
+     *     | CompareExpression()
+     *     | PlusExpression()
+     *     | MinusExpression()
+     *     | TimesExpression()
+     *     | ArrayLookup()
+     *     | ArrayLength()
+     *     | MessageSend()
+     *     | PrimaryExpression()
+     */
+    public TypeInstance visit(Expression n, SymbolTable symt) {
+        ++this.offset;
+        this.printNode(n, symt, true, null);
+
+        TypeInstance ret = n.f0.accept(this, symt);
+
+        this.printNode(n, symt, false, ret.getType());
+        --this.offset;
+        return ret;
+    }
+
+    /**
+     * DONE [28]: If expressions are both booleans, return is a boolean
+     *
+     * f0 -> PrimaryExpression()
+     * f1 -> "&&"
+     * f2 -> PrimaryExpression()
+     */
+    public TypeInstance visit(AndExpression n, SymbolTable symt) {
+        ++this.offset;
+        this.printNode(n, symt, true, null);
+
+        TypeInstance oper1 = n.f0.accept(this, symt);
+        n.f1.accept(this, symt);
+        TypeInstance oper2 = n.f2.accept(this, symt);
+        TypeInstance ret = (oper1.getType() == TypeEnum.bool &&
+                            oper2.getType() == TypeEnum.bool) ?
+            new TypeInstance(null, TypeEnum.bool) :
+            new TypeInstance(null, TypeEnum.ERROR);
+
+        this.printNode(n, symt, false, ret.getType());
+        --this.offset;
+        return ret;
+    }
+
+    /**
+     * DONE [29]: If expressions are both integers, return is a boolean
+     *
+     * f0 -> PrimaryExpression()
+     * f1 -> "<"
+     * f2 -> PrimaryExpression()
+     */
+    public TypeInstance visit(CompareExpression n, SymbolTable symt) {
+        ++this.offset;
+        this.printNode(n, symt, true, null);
+
+        TypeInstance oper1 = n.f0.accept(this, symt);
+        n.f1.accept(this, symt);
+        TypeInstance oper2 = n.f2.accept(this, symt);
+        TypeInstance ret = (oper1.getType() == TypeEnum.integer &&
+                            oper2.getType() == TypeEnum.integer) ?
+            new TypeInstance(null, TypeEnum.bool) :
+            new TypeInstance(null, TypeEnum.ERROR);
+
+        this.printNode(n, symt, false, ret.getType());
+        --this.offset;
+        return ret;
+    }
+
+    /**
+     * DONE [30]: If expressions are both integers, return is an integer
+     *
+     * f0 -> PrimaryExpression()
+     * f1 -> "+"
+     * f2 -> PrimaryExpression()
+     */
+    public TypeInstance visit(PlusExpression n, SymbolTable symt) {
+        ++this.offset;
+        this.printNode(n, symt, true, null);
+
+        TypeInstance oper1 = n.f0.accept(this, symt);
+        n.f1.accept(this, symt);
+        TypeInstance oper2 = n.f2.accept(this, symt);
+        TypeInstance ret = (oper1.getType() == TypeEnum.integer &&
+                            oper2.getType() == TypeEnum.integer) ?
+            new TypeInstance(null, TypeEnum.integer) :
+            new TypeInstance(null, TypeEnum.ERROR);
+
+        this.printNode(n, symt, false, ret.getType());
+        --this.offset;
+        return ret;
+    }
+
+    /**
+     * DONE [31]: If expressions are both integers, return is an integer
+     *
+     * f0 -> PrimaryExpression()
+     * f1 -> "-"
+     * f2 -> PrimaryExpression()
+     */
+    public TypeInstance visit(MinusExpression n, SymbolTable symt) {
+        ++this.offset;
+        this.printNode(n, symt, true, null);
+
+        TypeInstance oper1 = n.f0.accept(this, symt);
+        n.f1.accept(this, symt);
+        TypeInstance oper2 = n.f2.accept(this, symt);
+        TypeInstance ret = (oper1.getType() == TypeEnum.integer &&
+                            oper2.getType() == TypeEnum.integer) ?
+            new TypeInstance(null, TypeEnum.integer) :
+            new TypeInstance(null, TypeEnum.ERROR);
+
+        this.printNode(n, symt, false, ret.getType());
+        --this.offset;
+        return ret;
+    }
+
+    /**
+     * DONE [32]: If expressions are both integers, return is an integer
+     *
+     * f0 -> PrimaryExpression()
+     * f1 -> "*"
+     * f2 -> PrimaryExpression()
+     */
+    public TypeInstance visit(TimesExpression n, SymbolTable symt) {
+        ++this.offset;
+        this.printNode(n, symt, true, null);
+
+        TypeInstance oper1 = n.f0.accept(this, symt);
+        n.f1.accept(this, symt);
+        TypeInstance oper2 = n.f2.accept(this, symt);
+        TypeInstance ret = (oper1.getType() == TypeEnum.integer &&
+                            oper2.getType() == TypeEnum.integer) ?
+            new TypeInstance(null, TypeEnum.integer) :
+            new TypeInstance(null, TypeEnum.ERROR);
+
+        this.printNode(n, symt, false, ret.getType());
+        --this.offset;
+        return ret;
+    }
+
+    /**
+     * DONE [33]: If expr1 is an integer array and expr2 is an int,
+     * return is an int
+     *
+     * f0 -> PrimaryExpression()
+     * f1 -> "["
+     * f2 -> PrimaryExpression()
+     * f3 -> "]"
+     */
+    public TypeInstance visit(ArrayLookup n, SymbolTable symt) {
+        ++this.offset;
+        this.printNode(n, symt, true, null);
+
+        TypeInstance array = n.f0.accept(this, symt);
+        n.f1.accept(this, symt);
+        TypeInstance index = n.f2.accept(this, symt);
+        n.f3.accept(this, symt);
+        TypeInstance ret = (array.getType() == TypeEnum.intarray &&
+                            index.getType() == TypeEnum.integer) ?
+            new TypeInstance(null, TypeEnum.integer) :
+            new TypeInstance(null, TypeEnum.ERROR);
+
+        this.printNode(n, symt, false, ret.getType());
+        --this.offset;
+        return ret;
+    }
+
+    /**
+     * DONE [34]: If expr1 is an integer array, return is an int
+     *
+     * f0 -> PrimaryExpression()
+     * f1 -> "."
+     * f2 -> "length"
+     */
+    public TypeInstance visit(ArrayLength n, SymbolTable symt) {
+        ++this.offset;
+        this.printNode(n, symt, true, null);
+
+        TypeInstance ret = n.f0.accept(this, symt);
+        n.f1.accept(this, symt);
+        n.f2.accept(this, symt);
+        ret = (ret.getType() == TypeEnum.intarray) ? new TypeInstance(null, TypeEnum.integer) :
+            new TypeInstance(null, TypeEnum.ERROR);
+
+        this.printNode(n, symt, false, ret.getType());
+        --this.offset;
+        return ret;
+    }
+
+    // FIXME FIXME FIXME
+    /**
+     * [35]: PrimaryExpr must be a classname, id must be a method name, expressionlist must be correct?
+     *
+     * f0 -> PrimaryExpression()
+     * f1 -> "."
+     * f2 -> Identifier()
+     * f3 -> "("
+     * f4 -> ( ExpressionList() )?
+     * f5 -> ")"
+     */
+    public TypeInstance visit(MessageSend n, SymbolTable symt) {
+        ++this.offset;
+        this.printNode(n, symt, true, null);
+
+        // this MUST be an instance of a class!
+        TypeInstance t = n.f0.accept(this, symt);
+        ClassInstance c = t.getClassInstance();
+        n.f1.accept(this, symt);
+        n.f2.accept(this, symt);
+        MethodInstance m = symt.getMethod(n.f2.f0.tokenImage);
+        n.f3.accept(this, symt);
+        n.f4.accept(this, symt);
+        n.f5.accept(this, symt);
+        --this.offset;
+        return (true) ?
+            new TypeInstance(null, m.getReturn()) :
+            new TypeInstance(null, TypeEnum.ERROR);
+    }
+
+    // FIXME
+    /**
+     * f0 -> Expression()
+     * f1 -> ( ExpressionRest() )*
+     */
+    public TypeInstance visit(ExpressionList n, SymbolTable symt) {
+        ++this.offset;
+        this.printNode(n, symt, true, null);
+
+        TypeInstance expr1 = n.f0.accept(this, symt);
+        TypeInstance exprr =  n.f1.accept(this, symt);
+        TypeInstance ret = (expr1.hasChecked() &&
+                            exprr.hasChecked()) ?
+            new TypeInstance(null, TypeEnum.CHECK) :
+            new TypeInstance(null, TypeEnum.ERROR);
+
+        this.printNode(n, symt, false, ret.getType());
+        --this.offset;
+        return ret;
+    }
+
+    /**
+     * f0 -> ","
+     * f1 -> Expression()
+     */
+    public TypeInstance visit(ExpressionRest n, SymbolTable symt) {
+        ++this.offset;
+        this.printNode(n, symt, true, null);
+
+        n.f0.accept(this, symt);
+        TypeInstance ret = n.f1.accept(this, symt);
+
+        this.printNode(n, symt, false, ret.getType());
+        --this.offset;
+        return ret;
+    }
+
+    /**
+     * f0 -> IntegerLiteral()
+     *     | TrueLiteral()
+     *     | FalseLiteral()
+     *     | Identifier()
+     *     | ThisExpression()
+     *     | ArrayAllocationExpression()
+     *     | AllocationExpression()
+     *     | NotExpression()
+     *     | BracketExpression()
+     */
+    public TypeInstance visit(PrimaryExpression n, SymbolTable symt) {
+        ++this.offset;
+        this.printNode(n, symt, true, null);
+
+        TypeInstance ret = n.f0.accept(this, symt);
+
+        this.printNode(n, symt, false, ret.getType());
+        --this.offset;
+        return ret;
+    }
+
+    /**
+     * DONE [36]: return is an int
+     *
+     *
+     * f0 -> <INTEGER_LITERAL>
+     */
+    public TypeInstance visit(IntegerLiteral n, SymbolTable symt) {
+        ++this.offset;
+        this.printNode(n, symt, true, null);
+
+        this.printNode(n, symt, false, TypeEnum.integer);
+        --this.offset;
+        return new TypeInstance(null, TypeEnum.integer);
+    }
+
+    /**
+     * DONE [37]: return is a bool
+     *
+     * f0 -> "true"
+     */
+    public TypeInstance visit(TrueLiteral n, SymbolTable symt) {
+        ++this.offset;
+        this.printNode(n, symt, true, null);
+
+        this.printNode(n, symt, false, TypeEnum.bool);
+        --this.offset;
+        return new TypeInstance(null, TypeEnum.bool);
+    }
+
+    /**
+     * DONE [38]: return is a bool
+     *
+     * f0 -> "false"
+     */
+    public TypeInstance visit(FalseLiteral n, SymbolTable symt) {
+        ++this.offset;
+        this.printNode(n, symt, true, null);
+
+        this.printNode(n, symt, false, TypeEnum.bool);
+        --this.offset;
+        return new TypeInstance(null, TypeEnum.bool);
+    }
+
+    // FIXME
+    /**
+     * [39]: id is a symbol in the current domain, return is id's type
+     *
+     * f0 -> <IDENTIFIER>
+     */
+    public TypeInstance visit(Identifier n, SymbolTable symt) {
+        ++this.offset;
+        this.printNode(n, symt, true, null);
+
+        TypeInstance type;
+        TypeInstance ret;
+        ClassInstance cls;
+        if ((cls = symt.getClass(n.f0.tokenImage)) != null) {
+            // covers "anonymous" instance
+            ret = new TypeInstance(cls.getName(),
+                                   TypeEnum.classname);
+            ret.addClassInstance(cls);
+        } else {
+            if ((type = symt.getType(n.f0.tokenImage)) != null) {
+                ret =  new TypeInstance(type.getName(),
+                                        type.getType());
+                ret.addClassInstance(type.getClassInstance());
+            } else
+                ret =  new TypeInstance(null, TypeEnum.ERROR);
+        }
+
+        this.printNode(n, symt, false, ret.getType());
+        --this.offset;
+        return ret;
+    }
+
+    // FIXME FIXME FIXME
+    /**
+     * [40]: method exists? but where is the token?
+     *
+     * f0 -> "this"
+     */
+    public TypeInstance visit(ThisExpression n, SymbolTable symt) {
+        ++this.offset;
+        this.printNode(n, symt, true, null);
+
+        n.f0.accept(this, symt);
+        TypeInstance ret = new TypeInstance(null, TypeEnum.CHECK);
+
+        this.printNode(n, symt, false, ret.getType());
+        --this.offset;
+        return ret;
+    }
+
+    /**
+     * DONE [41]: if expression is an integer, return is an int array
+     *
+     * f0 -> "new"
+     * f1 -> "int"
+     * f2 -> "["
+     * f3 -> Expression()
+     * f4 -> "]"
+     */
+    public TypeInstance visit(ArrayAllocationExpression n, SymbolTable symt) {
+        ++this.offset;
+        this.printNode(n, symt, true, null);
+
+        n.f0.accept(this, symt);
+        n.f1.accept(this, symt);
+        n.f2.accept(this, symt);
+        TypeInstance ret = n.f3.accept(this, symt);
+        n.f4.accept(this, symt);
+        ret = (ret.getType() == TypeEnum.integer) ? new TypeInstance(null, TypeEnum.intarray) :
+            new TypeInstance(null, TypeEnum.ERROR);
+
+        this.printNode(n, symt, false, ret.getType());
+        --this.offset;
+        return ret;
+    }
+
+    // FIXME
+    /**
+     * [42]:
+     *
+     * f0 -> "new"
+     * f1 -> Identifier()
+     * f2 -> "("
+     * f3 -> ")"
+     */
+    public TypeInstance visit(AllocationExpression n, SymbolTable symt) {
+        ++this.offset;
+        this.printNode(n, symt, true, null);
+
+        n.f0.accept(this, symt);
+        TypeInstance ret = n.f1.accept(this, symt);
+        n.f2.accept(this, symt);
+        n.f3.accept(this, symt);
+
+        this.printNode(n, symt, false, ret.getType());
+        --this.offset;
+        return ret;
+    }
+
+    /**
+     * [43]: if expression is a boolean, return is a boolean
+     *
+     * f0 -> "!"
+     * f1 -> Expression()
+     */
+    public TypeInstance visit(NotExpression n, SymbolTable symt) {
+        ++this.offset;
+        this.printNode(n, symt, true, null);
+
+        n.f0.accept(this, symt);
+        TypeInstance ret = n.f1.accept(this, symt);
+
+        this.printNode(n, symt, false, ret.getType());
+        --this.offset;
+        return (ret.getType() == TypeEnum.bool) ? ret : new TypeInstance(null, TypeEnum.ERROR);
+    }
+
+    /**
+     * [44]: if e is a type, return is that same type
+     *
+     * f0 -> "("
+     * f1 -> Expression()
+     * f2 -> ")"
+     */
+    public TypeInstance visit(BracketExpression n, SymbolTable symt) {
+        ++this.offset;
+        this.printNode(n, symt, true, null);
+
+        n.f0.accept(this, symt);
+        TypeInstance ret = n.f1.accept(this, symt);
+        n.f2.accept(this, symt);
+
+        this.printNode(n, symt, false, ret.getType());
+        --this.offset;
+        return ret;
+    }
+
+}