root/trunk/ProjectFortress/src/com/sun/fortress/parser_util/FortressUtil.java @ 2045

/*******************************************************************************
    Copyright 2008 Sun Microsystems, Inc.,
    4150 Network Circle, Santa Clara, California 95054, U.S.A.
    All rights reserved.

    U.S. Government Rights - Commercial software.
    Government users are subject to the Sun Microsystems, Inc. standard
    license agreement and applicable provisions of the FAR and its supplements.

    Use is subject to license terms.

    This distribution may include materials developed by third parties.

    Sun, Sun Microsystems, the Sun logo and Java are trademarks or registered
    trademarks of Sun Microsystems, Inc. in the U.S. and other countries.
 ******************************************************************************/

/*
 * Utility functions for the Fortress com.sun.fortress.interpreter.parser.
 */

package com.sun.fortress.parser_util;

import java.lang.reflect.Array;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import edu.rice.cs.plt.iter.IterUtil;
import edu.rice.cs.plt.tuple.Option;
import edu.rice.cs.plt.tuple.OptionVisitor;

import com.sun.fortress.nodes.*;
import com.sun.fortress.nodes_util.Span;
import com.sun.fortress.nodes_util.SourceLoc;
import com.sun.fortress.nodes_util.ExprFactory;
import com.sun.fortress.nodes_util.NodeFactory;
import com.sun.fortress.useful.Cons;
import com.sun.fortress.useful.Pair;
import com.sun.fortress.useful.PureList;
import com.sun.fortress.exceptions.ProgramError;

import static com.sun.fortress.exceptions.InterpreterBug.bug;
import static com.sun.fortress.exceptions.ProgramError.error;

public final class FortressUtil {
    public static <T> T syntaxError(Span span, String msg) {
        return ProgramError.<T>error(new VoidLiteralExpr(span), msg);
    }

    public static void println(String arg) {
        System.out.println(arg);
    }

    public static Contract emptyContract() {
        return new Contract(new Span(), Option.<List<Expr>>none(),
                            Option.<List<EnsuresClause>>none(),
                            Option.<List<Expr>>none());
    }

    public static List<Decl> emptyDecls() {
        return Collections.<Decl>emptyList();
    }

    public static List<EnsuresClause> emptyEnsuresClauses() {
        return Collections.<EnsuresClause>emptyList();
    }

    public static List<Expr> emptyExprs() {
        return Collections.<Expr>emptyList();
    }

    public static List<Modifier> emptyModifiers() {
        return Collections.<Modifier>emptyList();
    }

    public static List<Param> emptyParams() {
        return Collections.<Param>emptyList();
    }

    public static List<StaticParam> emptyStaticParams() {
        return Collections.<StaticParam>emptyList();
    }

    public static List<BaseType> emptyTraitTypes() {
        return Collections.<BaseType>emptyList();
    }

    public static List<TraitTypeWhere> emptyTraitTypeWheres() {
        return Collections.<TraitTypeWhere>emptyList();
    }

    public static List<Type> emptyTypes() {
        return Collections.<Type>emptyList();
    }

    public static WhereClause emptyWhereClause() {
        return new WhereClause(Collections.<WhereBinding>emptyList(),
                               Collections.<WhereConstraint>emptyList());
    }

    public static Effect emptyEffect() {
        return new Effect();
    }

    public static <T> List<T> getListVal(Option<List<T>> o) {
        return o.unwrap(Collections.<T>emptyList());
    }

    public static <U, T extends U> List<U> mkList(T first) {
        List<U> l = new ArrayList<U>();
        l.add(first);
        return l;
    }

    public static <U, T extends U> List<U> mkList(List<T> all) {
        List<U> l = new ArrayList<U>();
        l.addAll(all);
        return l;
    }

    public static <U, T extends U> List<U> mkList(T first, T second) {
        List<U> l = new ArrayList<U>();
        l.add(first);
        l.add(second);
        return l;
    }

    public static <U, T extends U> List<U> mkList(U first, List<T> rest) {
        List<U> l = new ArrayList<U>();
        l.add(first);
        l.addAll(rest);
        return l;
    }

    public static <U, T extends U> List<U> mkList(List<T> rest, U last) {
        List<U> l = new ArrayList<U>();
        l.addAll(rest);
        l.add(last);
        return l;
    }

    public static List<LValue> toLValueList(List<LValueBind> lvbs) {
        List<LValue> result = new ArrayList<LValue>();
        for (LValueBind lvb : lvbs) {
            result.add((LValue)lvb);
        }
        return result;
    }

    public static List<Type> toTypeList(List<BaseType> tys) {
        List<Type> result = new ArrayList<Type>();
        for (BaseType ty : tys) {
            result.add((Type)ty);
        }
        return result;
    }

    public static Option<List<Type>> toTypeList(Option<List<BaseType>> tys) {
        return tys.apply(new OptionVisitor<List<BaseType>, Option<List<Type>>>() {
            public Option<List<Type>> forSome(List<BaseType> l) {
                return Option.<List<Type>>some(new ArrayList<Type>(l));
            }
            public Option<List<Type>> forNone() { return Option.none(); }
        });
    }

    public static Expr makeSubscripting(Span span, Span spanOpen, Span spanClose,
                                        String left, String right,
                                        Expr base, List<Expr> args,
                                        List<StaticArg> sargs) {
        Op open  = NodeFactory.makeOpEnclosing(spanOpen, left);
        Op close = NodeFactory.makeOpEnclosing(spanClose, right);
        return makeSubscripting(span, base, open, close, args, sargs);
    }

    public static Expr makeSubscripting(Span span, Expr base, Op open,
                                        Op close, List<Expr> args,
                                        List<StaticArg> sargs) {
        Enclosing op = new Enclosing(FortressUtil.spanTwo(open,close),
                                     open, close);
        List<Expr> es;
        if (args == null) es = FortressUtil.emptyExprs();
        else              es = args;
        return new SubscriptExpr(span, false, base, es, Option.some(op), sargs);
    }

    public static Expr makeSubscripting(Span span, Span spanOpen, Span spanClose,
                                        String left, String right,
                                        PureList<Expr> base, List<Expr> args,
                                        List<StaticArg> sargs) {
        Op open  = NodeFactory.makeOpEnclosing(spanOpen, left);
        Op close = NodeFactory.makeOpEnclosing(spanClose, right);
        return makeSubscripting(span, base, open, close, args, sargs);
    }

    public static Expr makeSubscripting(Span span, PureList<Expr> base, Op open,
                                        Op close, List<Expr> args,
                                        List<StaticArg> sargs) {
        Enclosing op = new Enclosing(FortressUtil.spanTwo(open,close),
                                     open, close);
        Expr arr = buildPrimary((PureList<Expr>)base);
        List<Expr> es;
        if (args == null) es = FortressUtil.emptyExprs();
        else              es = args;
        return new SubscriptExpr(span, false, arr, es, Option.some(op), sargs);
    }

    private static void multiple(Modifier m) {
        resetMods();
        syntaxError(m.getSpan(), "A modifier must not occur multiple times");
    }
    static boolean m_atomic   = false;
    static boolean m_getter   = false;
    static boolean m_hidden   = false;
    static boolean m_io       = false;
    static boolean m_private  = false;
    static boolean m_settable = false;
    static boolean m_setter   = false;
    static boolean m_test     = false;
    static boolean m_value    = false;
    static boolean m_var      = false;
    static boolean m_widens   = false;
    static boolean m_wrapped  = false;
    private static void resetMods() {
        m_atomic   = false;
        m_getter   = false;
        m_hidden   = false;
        m_io       = false;
        m_private  = false;
        m_settable = false;
        m_setter   = false;
        m_test     = false;
        m_value    = false;
        m_var      = false;
        m_widens   = false;
        m_wrapped  = false;
    }
    public static void noDuplicate(List<Modifier> mods) {
        for (Modifier mod : mods) {
            mod.accept(new NodeDepthFirstVisitor_void() {
                    public void forModifierAtomic(ModifierAtomic m) {
                        if (m_atomic) multiple(m);
                        else m_atomic = true;
                    }
                    public void forModifierGetter(ModifierGetter m) {
                        if (m_getter) multiple(m);
                        else m_getter = true;
                    }
                    public void forModifierHidden(ModifierHidden m) {
                        if (m_hidden) multiple(m);
                        else m_hidden = true;
                    }
                    public void forModifierIO(ModifierIO m) {
                        if (m_io) multiple(m);
                        else m_io = true;
                    }
                    public void forModifierPrivate(ModifierPrivate m) {
                        if (m_private) multiple(m);
                        else m_private = true;
                    }
                    public void forModifierSettable(ModifierSettable m) {
                        if (m_settable) multiple(m);
                        else m_settable = true;
                    }
                    public void forModifierSetter(ModifierSetter m) {
                        if (m_setter) multiple(m);
                        else m_setter = true;
                    }
                    public void forModifierTest(ModifierTest m) {
                        if (m_test) multiple(m);
                        else m_test = true;
                    }
                    public void forModifierValue(ModifierValue m) {
                        if (m_value) multiple(m);
                        else m_value = true;
                    }
                    public void forModifierVar(ModifierVar m) {
                        if (m_var) multiple(m);
                        else m_var = true;
                    }
                    public void forModifierWidens(ModifierWidens m) {
                        if (m_widens) multiple(m);
                        else m_widens = true;
                    }
                    public void forModifierWrapped(ModifierWrapped m) {
                        if (m_wrapped) multiple(m);
                        else m_wrapped = true;
                    }
                });
        }
        resetMods();
    }

    /* true is there exists a self parameter in a given parameter list */
    public static boolean isFunctionalMethod(List<Param> params) {
        for (Param p : params) {
            if (p.getName().getText().equals("self")) return true;
        }
        return false;
    }

    public static boolean validId(String s) {
        return (!FortressUtil.validOp(s) && !s.equals("_") &&
                !s.equals("SUM") && !s.equals("PROD"));
    }

    private static boolean compoundOp(String s) {
        return (s.length() > 1 && s.endsWith("=")
                && !s.equals("<=") && !s.equals(">=")
                && !s.equals("=/=") && !s.equals("==="));
    }
    private static boolean validOpChar(char c) {
        return (c == '_' || java.lang.Character.isUpperCase(c));
    }
    public static boolean validOp(String s) {
        if (s.equals("juxtaposition") || s.equals("in") || s.equals("per") ||
            s.equals("square") || s.equals("cubic") || s.equals("inverse") ||
            s.equals("squared") || s.equals("cubed"))
            return true;
        if (s.equals("SUM") || s.equals("PROD")) return false;
        int length = s.length();
        if (length < 2 || compoundOp(s)) return false;
        char start = s.charAt(0);
        if (length == 2 && start == s.charAt(1)) return false;
        if (length > 2 && start == s.charAt(1) && s.charAt(2) == '_')
            return false;
        if (start == '_' || s.endsWith("_")) return false;
        for (int i = 0; i < length; i++) {
            if (!validOpChar(s.charAt(i))) return false;
        }
        return true;
    }

    public static boolean getMutable(List<Modifier> mods) {
        for (Modifier m : mods) {
            if (m instanceof ModifierVar || m instanceof ModifierSettable)
                return true;
        }
        return false;
    }

    public static List<LValueBind> setMutable(List<LValueBind> vars) {
        List<LValueBind> result = new ArrayList<LValueBind>();
        for (LValueBind l : vars) {
            result.add(NodeFactory.makeLValue(l, true));
        }
        return result;
    }

    public static List<LValueBind> setMutable(List<LValueBind> vars, Span span) {
        List<LValueBind> result = new ArrayList<LValueBind>();
        for (LValueBind l : vars) {
            List<Modifier> mods = new ArrayList<Modifier>();
            mods.add(new ModifierVar(span));
            result.add(NodeFactory.makeLValue(l, mods));
        }
        return result;
    }

    public static List<LValueBind> setMods(List<LValueBind> vars,
                                           List<Modifier> mods) {
        List<LValueBind> result = new ArrayList<LValueBind>();
        for (LValueBind l : vars) {
            result.add(NodeFactory.makeLValue(l, mods));
        }
        return result;
    }

    public static List<LValueBind> setModsAndMutable(List<LValueBind> vars,
                                                     List<Modifier> mods) {
        List<LValueBind> result = new ArrayList<LValueBind>();
        for (LValueBind l : vars) {
            result.add(NodeFactory.makeLValue(l, mods, true));
        }
        return result;
    }

    public static List<LValue> setMutableLValue(List<LValue> vars, Span span) {
        List<LValue> result = new ArrayList<LValue>();
        for (LValue l : vars) {
            if (l instanceof LValueBind) {
                List<Modifier> mods = new ArrayList<Modifier>();
                mods.add(new ModifierVar(span));
                result.add(NodeFactory.makeLValue((LValueBind)l, mods));
            } else syntaxError(l.getSpan(), "Unpasting cannot be mutable.");
        }
        return result;
    }

    public static List<LValue> setType(List<LValue> vars, Type ty) {
        List<LValue> result = new ArrayList<LValue>();
        for (LValue l : vars) {
            if (l instanceof LValueBind)
                result.add(NodeFactory.makeLValue((LValueBind)l, ty));
            else syntaxError(l.getSpan(), "Unpasting cannot be set types.");
        }
        return result;
    }

    public static List<LValue> setType(List<LValue> vars, List<Type> tys) {
        List<LValue> result = new ArrayList<LValue>();
        int ind = 0;
        for (LValue l : vars) {
            if (l instanceof LValueBind) {
                result.add(NodeFactory.makeLValue((LValueBind)l, tys.get(ind)));
                ind += 1;
            } else syntaxError(l.getSpan(), "Unpasting cannot be set types.");
        }
        return result;
    }

    public static List<LValue> setMutableAndType(List<LValue> vars, Type ty) {
        List<LValue> result = new ArrayList<LValue>();
        for (LValue l : vars) {
            if (l instanceof LValueBind) {
                result.add(NodeFactory.makeLValue((LValueBind)l, ty, true));
            } else syntaxError(l.getSpan(), "Unpasting cannot be mutable.");
        }
        return result;
    }

    public static List<LValue> setMutableAndType(List<LValue> vars, Span span,
                                                 Type ty) {
        List<LValue> result = new ArrayList<LValue>();
        for (LValue l : vars) {
           if (l instanceof LValueBind) {
               List<Modifier> mods = new ArrayList<Modifier>();
               mods.add(new ModifierVar(span));
               result.add(NodeFactory.makeLValue((LValueBind)l, ty, mods));
           } else syntaxError(l.getSpan(), "Unpasting cannot be mutable.");
        }
        return result;
    }

    public static List<LValue> setMutableAndType(List<LValue> vars,
                                                 List<Type> tys) {
        List<LValue> result = new ArrayList<LValue>();
        int ind = 0;
        for (LValue l : vars) {
            if (l instanceof LValueBind) {
                result.add(NodeFactory.makeLValue((LValueBind)l, tys.get(ind),
                                                  true));
                ind += 1;
            } else syntaxError(l.getSpan(), "Unpasting cannot be mutable.");
        }
        return result;
    }

    public static List<LValue> setMutableAndType(List<LValue> vars, Span span,
                                                 List<Type> tys) {
        List<LValue> result = new ArrayList<LValue>();
        int ind = 0;
        for (LValue l : vars) {
            if (l instanceof LValueBind) {
               List<Modifier> mods = new ArrayList<Modifier>();
               mods.add(new ModifierVar(span));
               result.add(NodeFactory.makeLValue((LValueBind)l, tys.get(ind),
                                                 mods));
               ind += 1;
            } else syntaxError(l.getSpan(), "Unpasting cannot be mutable.");
        }
        return result;
    }

    public static List<LValueBind> ids2Lvs(List<Id> ids, List<Modifier> mods,
                                           Option<Type> ty, boolean mutable) {
        List<LValueBind> lvs = new ArrayList<LValueBind>();
        for (Id id : ids) {
            lvs.add(new LValueBind(id.getSpan(), id, ty, mods, mutable));
        }
        return lvs;
    }

    public static List<LValueBind> ids2Lvs(List<Id> ids, List<Modifier> mods,
                                           Type ty, boolean mutable) {
        return ids2Lvs(ids, mods, Option.some(ty), mutable);
    }

    public static List<LValueBind> ids2Lvs(List<Id> ids, Type ty,
                                           boolean mutable) {
        return ids2Lvs(ids, emptyModifiers(), Option.some(ty), mutable);
    }

    public static List<LValueBind> ids2Lvs(List<Id> ids, List<Modifier> mods) {
        return ids2Lvs(ids, mods, Option.<Type>none(), false);
    }

    public static List<LValueBind> ids2Lvs(List<Id> ids) {
        return ids2Lvs(ids, emptyModifiers(), Option.<Type>none(), false);
    }

    public static List<LValueBind> ids2Lvs(List<Id> ids, List<Modifier> mods,
                                           List<Type> tys, boolean mutable) {
        List<LValueBind> lvs = new ArrayList<LValueBind>();
        int ind = 0;
        for (Id id : ids) {
            lvs.add(new LValueBind(id.getSpan(), id, Option.some(tys.get(ind)),
                                   mods, mutable));
            ind += 1;
        }
        return lvs;
    }

    public static List<LValueBind> ids2Lvs(List<Id> ids, List<Type> tys,
                                           boolean mutable) {
        return ids2Lvs(ids, emptyModifiers(), tys, mutable);
    }

    public static AbsFnDecl mkAbsFnDecl(Span span, List<Modifier> mods,
                                        Option<Id> receiver,
                                        FnHeaderFront fhf, FnHeaderClause fhc) {
        Option<List<BaseType>> throws_ = fhc.getThrowsClause();
        WhereClause where_ = fhc.getWhereClause();
        Contract contract = fhc.getContractClause().unwrap(emptyContract());
        return NodeFactory.makeAbsFnDecl(span, mods, receiver, fhf.getName(),
                                         fhf.getStaticParams(), fhf.getParams(),
                                         fhc.getReturnType(), throws_, where_,
                                         contract);
    }

    public static AbsFnDecl mkAbsFnDecl(Span span, List<Modifier> mods,
                                        FnHeaderFront fhf, FnHeaderClause fhc) {
        return mkAbsFnDecl(span, mods, Option.<Id>none(), fhf, fhc);
    }

    public static AbsFnDecl mkAbsFnDecl(Span span, List<Modifier> mods,
                                        IdOrOpOrAnonymousName name, List<StaticParam> sparams,
                                        List<Param> params,
                                        FnHeaderClause fhc) {
        Option<List<BaseType>> throws_ = fhc.getThrowsClause();
        WhereClause where_ = fhc.getWhereClause();
        Contract contract = fhc.getContractClause().unwrap(emptyContract());
        return NodeFactory.makeAbsFnDecl(span, mods, Option.<Id>none(), name,
                                         sparams, params,
                                         Option.<Type>none(), throws_,
                                         where_, contract);
    }

    public static AbsFnDecl mkAbsFnDecl(Span span, List<Modifier> mods,
                                        IdOrOpOrAnonymousName name, List<Param> params,
                                        Type ty) {
        return NodeFactory.makeAbsFnDecl(span, mods, Option.<Id>none(), name,
                                         emptyStaticParams(), params,
                                         Option.some(ty),
                                         Option.<List<BaseType>>none(),
                                         emptyWhereClause(), emptyContract());
    }

    public static FnDef mkFnDecl(Span span, List<Modifier> mods,
                                 Option<Id> receiver, FnHeaderFront fhf,
                                 FnHeaderClause fhc, Expr expr) {
        Option<List<BaseType>> throws_ = fhc.getThrowsClause();
        WhereClause where_ = fhc.getWhereClause();
        Contract contract = fhc.getContractClause().unwrap(emptyContract());
        return NodeFactory.makeFnDecl(span, mods, receiver, fhf.getName(),
                                      fhf.getStaticParams(), fhf.getParams(),
                                      fhc.getReturnType(), throws_, where_,
                                      contract, expr);
    }

    public static FnDef mkFnDecl(Span span, List<Modifier> mods, IdOrOpOrAnonymousName name,
                                 List<StaticParam> sparams, List<Param> params,
                                 FnHeaderClause fhc, Expr expr) {
        Option<List<BaseType>> throws_ = fhc.getThrowsClause();
        WhereClause where_ = fhc.getWhereClause();
        Contract contract = fhc.getContractClause().unwrap(emptyContract());
        return NodeFactory.makeFnDecl(span, mods, Option.<Id>none(), name,
                                      sparams, params, Option.<Type>none(),
                                      throws_, where_, contract, expr);
    }

    public static FnDef mkFnDecl(Span span, List<Modifier> mods,
                                 FnHeaderFront fhf, FnHeaderClause fhc,
                                 Expr expr) {
        return mkFnDecl(span, mods, Option.<Id>none(), fhf, fhc, expr);
    }

    public static LocalVarDecl mkLocalVarDecl(Span span, List<LValue> lvs,
                                              Option<Expr> expr) {
        return new LocalVarDecl(span, false, emptyExprs(), lvs, expr);
    }
    public static LocalVarDecl mkLocalVarDecl(Span span, List<LValue> lvs,
                                              Expr expr) {
        return new LocalVarDecl(span, false, emptyExprs(), lvs,
                                Option.some(expr));
    }
    public static LocalVarDecl mkLocalVarDecl(Span span, List<LValue> lvs) {
        return new LocalVarDecl(span, false, emptyExprs(), lvs,
                                Option.<Expr>none());
    }

    public static LValueBind mkLValueBind(Span span, Id id, Type ty) {
        return new LValueBind(span, id, Option.some(ty), emptyModifiers(),false);
    }
    public static LValueBind mkLValueBind(Span span, Id id) {
        return new LValueBind(span, id, Option.<Type>none(),
                              emptyModifiers(), false);
    }
    public static LValueBind mkLValueBind(Id id, Type ty,
                                          List<Modifier> mods) {
        return new LValueBind(id.getSpan(), id, Option.some(ty), mods,
                              getMutable(mods));
    }
    public static LValueBind mkLValueBind(Id id, Type ty) {
        return mkLValueBind(id, ty, emptyModifiers());
    }

// let rec multi_dim_cons (expr : expr)
//                        (dim : int)
//                        (multi : multi_dim_expr) : multi_dim_expr =
//   let elem = multi_dim_elem expr in
//   let span = span_two expr multi in
//     match multi.node_data with
//       | `ArrayElement _ ->
//           multi_dim_row span dim [ elem; multi ]
//       | `ArrayElements
//           { node_span = row_span;
//             node_data =
//               { multi_dim_row_dimension = row_dim;
//                 multi_dim_row_elements = elements; } } ->
//           if dim = row_dim
//           then multi_dim_row span dim (elem :: elements)
//           else if dim > row_dim
//           then multi_dim_row span dim [ elem; multi ]
//           else
//             (match elements with
//                | [] -> Errors.internal_error row_span
//                    "empty array/matrix literal"
//                | first::rest ->
//                    multi_dim_row span row_dim
//                      (multi_dim_cons expr dim first :: rest))
    private static ArrayExpr multiDimElement(Expr expr) {
        return new ArrayElement(expr.getSpan(), false, expr);
    }
    private static ArrayElements addOneMultiDim(ArrayExpr multi, int dim,
                                              Expr expr){
        Span span = spanTwo(multi, expr);
        ArrayExpr elem = multiDimElement(expr);
        if (multi instanceof ArrayElement) {
            List<ArrayExpr> elems = new ArrayList<ArrayExpr>();
            elems.add(multi);
            elems.add(elem);
            return new ArrayElements(span, false, dim, elems);
        } else if (multi instanceof ArrayElements) {
            ArrayElements m = (ArrayElements)multi;
            int _dim = m.getDimension();
            List<ArrayExpr> elements = m.getElements();
            if (dim == _dim) {
                elements.add(elem);
                return new ArrayElements(span, false, dim, elements);
            } else if (dim > _dim) {
                List<ArrayExpr> elems = new ArrayList<ArrayExpr>();
                elems.add(multi);
                elems.add(elem);
                return new ArrayElements(span, false, dim, elems);
            } else if (elements.size() == 0) {
                return syntaxError(multi.getSpan(),
                                   "Empty array/matrix literal.");
            } else { // if (dim < _dim)
                int index = elements.size()-1;
                ArrayExpr last = elements.get(index);
                elements.set(index, addOneMultiDim(last, dim, expr));
                return new ArrayElements(span, false, _dim, elements);
            }
        } else {
            return syntaxError(multi.getSpan(),
                               "ArrayElement or ArrayElements is expected.");
        }
    }
    public static ArrayExpr multiDimCons(Expr init,
                                        List<Pair<Integer,Expr>> rest) {
        ArrayExpr _init = multiDimElement(init);
        if (rest.isEmpty()) {
            return bug(init, "multiDimCons: empty rest");
        } else {
            Pair<Integer,Expr> pair = rest.get(0);
            Expr expr = pair.getB();
            List<ArrayExpr> elems = new ArrayList<ArrayExpr>();
            elems.add(_init);
            elems.add(multiDimElement(expr));
            ArrayElements result = new ArrayElements(spanTwo(_init,expr), false,
                                                     pair.getA(), elems);
            for (Pair<Integer,Expr> _pair : rest.subList(1, rest.size())) {
                int _dim   = _pair.getA();
                Expr _expr = _pair.getB();
                Span span = spanTwo(result, _expr);
                result = addOneMultiDim(result, _dim, _expr);
            }
            return result;
        }
    }

    public static ArrayExpr addStaticArgsToArrayExpr(List<StaticArg> sargs,
                                              ArrayExpr a) {
        if (a instanceof ArrayElement) {
            ArrayElement arrayE = (ArrayElement)a;
            return new ArrayElement(arrayE.getSpan(), arrayE.isParenthesized(),
                                    sargs, arrayE.getElement());
        } else { // a instanceof ArrayElements
            ArrayElements arrayE = (ArrayElements)a;
            return new ArrayElements(arrayE.getSpan(), arrayE.isParenthesized(),
                                     sargs, arrayE.getDimension(),
                                     arrayE.getElements());
        }
    }

// let rec unpasting_cons (span : span)
//                        (one : unpasting)
//                        (sep : int)
//                        (two : unpasting) : unpasting =
//   match two.node_data with
//     | `UnpastingBind _ | `UnpastingNest _ -> unpasting_split span sep [one;two]
//     | `UnpastingSplit split ->
//         (match split.node_data with
//            | { unpasting_split_elems = (head :: tail) as elems;
//                unpasting_split_dim = dim; } ->
//                if sep > dim then unpasting_split span sep [one;two]
//                else if sep < dim then
//                  unpasting_split span dim
//                    (unpasting_cons (span_two one head) one sep head :: tail)
//                else (* sep = dim *)
//                  unpasting_split span dim (one :: elems)
//            | _ -> Errors.internal_error span "Empty unpasting.")
    public static Unpasting unpastingCons(Span span, Unpasting one, int sep,
                                          Unpasting two) {
        List<Unpasting> onetwo = new ArrayList<Unpasting>();
        onetwo.add(one);
        onetwo.add(two);
        if (two instanceof UnpastingBind) {
            return new UnpastingSplit(span, onetwo, sep);
        } else if (two instanceof UnpastingSplit) {
            UnpastingSplit split = (UnpastingSplit)two;
            List<Unpasting> elems = split.getElems();
            if (elems.size() != 0) {
                int dim = split.getDim();
                if (sep > dim) {
                    return new UnpastingSplit(span, onetwo, sep);
                } else if (sep < dim) {
                    Unpasting head = elems.get(0);
                    elems.set(0, unpastingCons(spanTwo(one,head),one,sep,head));
                    return new UnpastingSplit(span, elems, dim);
                } else { // sep = dim
                    elems.add(0, one);
                    return new UnpastingSplit(span, elems, dim);
                }
            } else { // elems.size() == 0
                return syntaxError(two.getSpan(), "Empty unpasting.");
            }
        } else { //    !(two instanceof UnpastingBind)
                 // && !(two instanceof UnpastingSplit)
            return bug(two, "UnpastingBind or UnpastingSplit expected.");
        }
    }

// let join (one : span) (two : span) : span =
//   match one, two with
//     | None, span | span, None -> span
//     | Some (left,_), Some (_,right) -> Some (left,right)

// let span_two (one : 'a node) (two : 'b node) : span =
//   join one.node_span two.node_span

    public static Span spanTwo(Node s1, Node s2) {
        return new Span(s1.getSpan().getBegin(), s2.getSpan().getEnd());
    }

    public static Span spanTwo(Span s1, Span s2) {
        return new Span(s1.getBegin(), s2.getEnd());
    }

// let rec span_all (com.sun.fortress.interpreter.nodes : 'a node list) : span =
//   match com.sun.fortress.interpreter.nodes with
//     | [] -> None
//     | node :: rest -> join node.node_span (span_all rest)
    public static Span spanAll(Object[] nodes, int size) {
        if (size == 0) return new Span();
        else { // size != 0
            return new Span(((Node)Array.get(nodes,0)).getSpan().getBegin(),
                            ((Node)Array.get(nodes,size-1)).getSpan().getEnd());
        }
    }

    public static Span spanAll(Iterable<? extends Node> nodes) {
        if (IterUtil.isEmpty(nodes)) { return new Span(); }
        else {
            return new Span(IterUtil.first(nodes).getSpan().getBegin(),
                            IterUtil.last(nodes).getSpan().getEnd());
        }
    }

    public static Span spanAll(SourceLoc defaultLoc, Iterable<? extends Node> nodes) {
        if (IterUtil.isEmpty(nodes)) { return new Span(defaultLoc, defaultLoc); }
        else {
            return new Span(IterUtil.first(nodes).getSpan().getBegin(),
                            IterUtil.last(nodes).getSpan().getEnd());
        }
    }

// let build_block (exprs : expr list) : expr list =
//   List_aux.foldr
//     (fun e es ->
//        match e.node_data with
//          | `LetExpr (le,[]) -> [{ e with node_data = `LetExpr (le, es) }]
//          | `LetExpr _ -> raise (Failure "misparsed variable introduction!")
//          | _ -> e :: es)
//     exprs
//     []
//
// let do_block (body : expr list) : expr =
//   let span = span_all body in
//     node span (`FlowExpr (node span (`BlockExpr (build_block body))))
    public static Block doBlock(Span span) {
        return new Block(span, false, emptyExprs());
    }

    public static Block doBlock(List<Expr> exprs) {
        Span span = spanAll(exprs.toArray(new AbstractNode[0]), exprs.size());
        List<Expr> es = new ArrayList<Expr>();
        Collections.reverse(exprs);
        for (Expr e : exprs) {
            if (e instanceof LetExpr) {
                LetExpr _e = (LetExpr)e;
                if (_e.getBody().isEmpty()) {
                    _e = ExprFactory.makeLetExpr(_e, es);
                    es = mkList((Expr)_e);
                } else {
                    syntaxError(e.getSpan(), "Misparsed variable introduction!");
                }
            } else {
                if (isEquality(e) && !e.isParenthesized())
                    syntaxError(e.getSpan(),
                                "Equality testing expressions should be parenthesized.");
                else es.add(0, e);
            }
        }
        return new Block(span, false, es);
    }

    private static boolean isEquality(Expr expr) {
        if (expr instanceof ChainExpr) {
            ChainExpr e = (ChainExpr)expr;
            List<Link> links = e.getLinks();
            if (links.size() == 1) {
                OpName op = links.get(0).getOp().getOriginalName();
                return (op instanceof Op && ((Op)op).getText().equals("="));
            } else return false;
        } else return false;
    }

// (* Turn an expr list into a single TightJuxt *)
// let build_primary (p : expr list) : expr =
//   match p with
//     | [e] -> e
//     | _ ->
//         let es = List.rev p in
//           Node.node (span_all es) (`TightJuxt es)
    public static Expr buildPrimary(PureList<Expr> exprs) {
        if (exprs.size() == 1) return ((Cons<Expr>)exprs).getFirst();
        else {
            exprs = exprs.reverse();
            List<Expr> javaList = exprs.toJavaList();
            return new TightJuxt(spanAll(javaList.toArray(new AbstractNode[0]),
                                         javaList.size()), false, javaList);
        }
    }
}