/* Compiler implementation of the D programming language
 * Copyright (C) 1999-2019 by The D Language Foundation, All Rights Reserved
 * written by Walter Bright
 * http://www.digitalmars.com
 * Distributed under the Boost Software License, Version 1.0.
 * http://www.boost.org/LICENSE_1_0.txt
 * https://github.com/D-Programming-Language/dmd/blob/master/src/sapply.c
 */

#include "root/dsystem.h"

#include "mars.h"
#include "statement.h"
#include "visitor.h"


/**************************************
 * A Statement tree walker that will visit each Statement s in the tree,
 * in depth-first evaluation order, and call fp(s,param) on it.
 * fp() signals whether the walking continues with its return value:
 * Returns:
 *      0       continue
 *      1       done
 * It's a bit slower than using virtual functions, but more encapsulated and less brittle.
 * Creating an iterator for this would be much more complex.
 */

class PostorderStatementVisitor : public StoppableVisitor
{
public:
    StoppableVisitor *v;
    PostorderStatementVisitor(StoppableVisitor *v) : v(v) {}

    bool doCond(Statement *s)
    {
        if (!stop && s)
            s->accept(this);
        return stop;
    }
    bool applyTo(Statement *s)
    {
        s->accept(v);
        stop = v->stop;
        return true;
    }

    void visit(Statement *s)
    {
        applyTo(s);
    }
    void visit(PeelStatement *s)
    {
        doCond(s->s) || applyTo(s);
    }
    void visit(CompoundStatement *s)
    {
        for (size_t i = 0; i < s->statements->dim; i++)
            if (doCond((*s->statements)[i]))
                return;
        applyTo(s);
    }
    void visit(UnrolledLoopStatement *s)
    {
        for (size_t i = 0; i < s->statements->dim; i++)
            if (doCond((*s->statements)[i]))
                return;
        applyTo(s);
    }
    void visit(ScopeStatement *s)
    {
        doCond(s->statement) || applyTo(s);
    }
    void visit(WhileStatement *s)
    {
        doCond(s->_body) || applyTo(s);
    }
    void visit(DoStatement *s)
    {
        doCond(s->_body) || applyTo(s);
    }
    void visit(ForStatement *s)
    {
        doCond(s->_init) || doCond(s->_body) || applyTo(s);
    }
    void visit(ForeachStatement *s)
    {
        doCond(s->_body) || applyTo(s);
    }
    void visit(ForeachRangeStatement *s)
    {
        doCond(s->_body) || applyTo(s);
    }
    void visit(IfStatement *s)
    {
        doCond(s->ifbody) || doCond(s->elsebody) || applyTo(s);
    }
    void visit(PragmaStatement *s)
    {
        doCond(s->_body) || applyTo(s);
    }
    void visit(SwitchStatement *s)
    {
        doCond(s->_body) || applyTo(s);
    }
    void visit(CaseStatement *s)
    {
        doCond(s->statement) || applyTo(s);
    }
    void visit(DefaultStatement *s)
    {
        doCond(s->statement) || applyTo(s);
    }
    void visit(SynchronizedStatement *s)
    {
        doCond(s->_body) || applyTo(s);
    }
    void visit(WithStatement *s)
    {
        doCond(s->_body) || applyTo(s);
    }
    void visit(TryCatchStatement *s)
    {
        if (doCond(s->_body))
            return;

        for (size_t i = 0; i < s->catches->dim; i++)
            if (doCond((*s->catches)[i]->handler))
                return;
        applyTo(s);
    }
    void visit(TryFinallyStatement *s)
    {
        doCond(s->_body) || doCond(s->finalbody) || applyTo(s);
    }
    void visit(OnScopeStatement *s)
    {
        doCond(s->statement) || applyTo(s);
    }
    void visit(DebugStatement *s)
    {
        doCond(s->statement) || applyTo(s);
    }
    void visit(LabelStatement *s)
    {
        doCond(s->statement) || applyTo(s);
    }
};

bool walkPostorder(Statement *s, StoppableVisitor *v)
{
    PostorderStatementVisitor pv(v);
    s->accept(&pv);
    return v->stop;
}