com.oracle.js.parser.ir.Expression Maven / Gradle / Ivy

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package com.oracle.js.parser.ir;

/**
 * Common superclass for all expression nodes. Expression nodes can have an associated symbol as
 * well as a type.
 *
 */
public abstract class Expression extends Node {
    /**
     * Determines whether this expression is enclosed in parenthesis.
     */
    private boolean parenthesized;
    private int parensStart;
    private int parensFinish;

    Expression(final long token, final int start, final int finish) {
        super(token, start, finish);
    }

    Expression(final long token, final int finish) {
        super(token, finish);
    }

    Expression(final Expression expr) {
        super(expr);
    }

    /**
     * Is this a self modifying assignment?
     *
     * @return true if self modifying, e.g. a++, or a*= 17
     */
    public boolean isSelfModifying() {
        return false;
    }

    /**
     * Returns true if the runtime value of this expression is always false when converted to
     * boolean as per ECMAScript ToBoolean conversion. Used in control flow calculations.
     *
     * @return true if this expression's runtime value converted to boolean is always false.
     */
    public boolean isAlwaysFalse() {
        return false;
    }

    /**
     * Returns true if the runtime value of this expression is always true when converted to boolean
     * as per ECMAScript ToBoolean conversion. Used in control flow calculations.
     *
     * @return true if this expression's runtime value converted to boolean is always true.
     */
    public boolean isAlwaysTrue() {
        return false;
    }

    /**
     * Determines whether this expression is enclosed in parenthesis.
     *
     * @return {@code true} if this expression is enclosed in parenthesis, returns {@code false}
     *         otherwise.
     */
    public final boolean isParenthesized() {
        return parenthesized;
    }

    /**
     * Marks this expression as enclosed in parenthesis.
     */
    public final void makeParenthesized(int parenStart, int parenFinish) {
        assert parenthesized ? (parenStart <= parensStart && parensFinish <= parenFinish) : (parenStart <= super.getStart() && super.getFinish() <= parenFinish);
        parenthesized = true;
        parensStart = parenStart;
        parensFinish = parenFinish;
    }

    @Override
    public int getStart() {
        return parenthesized ? parensStart : super.getStart();
    }

    public final int getStartWithoutParens() {
        return super.getStart();
    }

    @Override
    public int getFinish() {
        return parenthesized ? parensFinish : super.getFinish();
    }

    public final int getFinishWithoutParens() {
        return super.getFinish();
    }

}