/* Alloy Analyzer 4 -- Copyright (c) 2006-2009, Felix Chang
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files
 * (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify,
 * merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
 * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
 * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF
 * OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */

package edu.mit.csail.sdg.alloy4compiler.ast;

import java.util.ArrayList;
import java.util.Collection;
import java.util.List;
import edu.mit.csail.sdg.alloy4.Pos;
import edu.mit.csail.sdg.alloy4.Err;
import edu.mit.csail.sdg.alloy4.ErrorWarning;

/** Immutable; represents a LET or QUANTIFICATION variable in the AST.
 *
 * <p> <b>Invariant:</b>  type!=EMPTY => (type==expr.type && !expr.ambiguous)
 */

public final class ExprVar extends ExprHasName {

    /** {@inheritDoc} */
    @Override public void toString(StringBuilder out, int indent) {
        if (indent<0) {
            out.append(label);
        } else {
            for(int i=0; i<indent; i++) { out.append(' '); }
            out.append("Var ").append(label).append(" at position <").append(pos).append("> with type=").append(type).append('\n');
        }
    }

    /** Constructs an ExprVar object */
    private ExprVar(Pos pos, String label, Type type) {
        super(pos, label, type);
    }

    /** Constructs an ExprVar variable with the EMPTY type
     * @param pos - the original position in the source file (can be null if unknown)
     * @param label - the label for this variable (it is only used for pretty-printing and does not have to be unique)
     */
    public static ExprVar make(Pos pos, String label) {
        return new ExprVar(pos, label, Type.EMPTY);
    }

    /** Constructs an ExprVar variable with the given type
     * @param pos - the original position in the source file (can be null if unknown)
     * @param label - the label for this variable (it is only used for pretty-printing and does not have to be unique)
     * @param type - the type
     */
    public static ExprVar make(Pos pos, String label, Type type) {
        return new ExprVar(pos, label, type);
    }

    /** {@inheritDoc} */
    @Override public Expr resolve(Type p, Collection<ErrorWarning> warns) { return this; }

    /** {@inheritDoc} */
    @Override public <T> T accept(VisitReturn<T> visitor) throws Err { return visitor.visit(this); }

    /** {@inheritDoc} */
    @Override public String getHTML() { return "<b>variable</b>: " + label + " <i>" + type + "</i>"; }

    /** {@inheritDoc} */
    @Override public List<? extends Browsable> getSubnodes() { return new ArrayList<Browsable>(0); }
}