Developer CD Series 1996 February: Tool Chest/Apple Developer CD Series Tool Chest February 1996 (Apple Computer)(1996).iso/Tool Chest/Development Tools & Languages/• Other Platforms/PCCTS 1.31/h/ASTBase.C

C/C++ Source or Header | 1995-03-10 | 5.0 KB | 185 lines | [TEXT/MPS ]

/* Abstract syntax tree manipulation functions
 *
 * SOFTWARE RIGHTS
 *
 * We reserve no LEGAL rights to the Purdue Compiler Construction Tool
 * Set (PCCTS) -- PCCTS is in the public domain.  An individual or
 * company may do whatever they wish with source code distributed with
 * PCCTS or the code generated by PCCTS, including the incorporation of
 * PCCTS, or its output, into commerical software.
 *
 * We encourage users to develop software with PCCTS.  However, we do ask
 * that credit is given to us for developing PCCTS.  By "credit",
 * we mean that if you incorporate our source code into one of your
 * programs (commercial product, research project, or otherwise) that you
 * acknowledge this fact somewhere in the documentation, research report,
 * etc...  If you like PCCTS and have developed a nice tool with the
 * output, please mention that you developed it using PCCTS.  In
 * addition, we ask that this header remain intact in our source code.
 * As long as these guidelines are kept, we expect to continue enhancing
 * this system and expect to make other tools available as they are
 * completed.
 *
 * ANTLR 1.31
 * Terence Parr
 * Parr Research Corporation
 * with Purdue University and AHPCRC, University of Minnesota
 * 1989-1995
 */
#include <stdio.h>
#include <stdarg.h>
#include "ASTBase.h"

/* ensure that tree manipulation variables are current after a rule
 * reference
 */
void
ASTBase::link(ASTBase **_root, ASTBase **_sibling, ASTBase **_tail)
{
    if ( *_sibling == NULL ) return;
    if ( *_root == NULL ) *_root = *_sibling;
    else if ( *_root != *_sibling ) (*_root)->_down = *_sibling;
    if ( *_tail==NULL ) *_tail = *_sibling;
    while ( (*_tail)->_right != NULL ) *_tail = (*_tail)->_right;
}

/* add a child node to the current sibling list */
void
ASTBase::subchild(ASTBase **_root, ASTBase **_sibling, ASTBase **_tail)
{
    if ( *_tail != NULL ) (*_tail)->_right = this;
    else {
        *_sibling = this;
        if ( *_root != NULL ) (*_root)->_down = *_sibling;
    }
    *_tail = this;
    if ( *_root == NULL ) *_root = *_sibling;
}

/* make a new AST node.  Make the newly-created
 * node the root for the current sibling list.  If a root node already
 * exists, make the newly-created node the root of the current root.
 */
void
ASTBase::subroot(ASTBase **_root, ASTBase **_sibling, ASTBase **_tail)
{
    if ( *_root != NULL )
        if ( (*_root)->_down == *_sibling ) *_sibling = *_tail = *_root;
    *_root = this;
    (*_root)->_down = *_sibling;
}

/* Apply preorder_action(), etc.. to root then each sibling */
void
ASTBase::preorder()
{
    ASTBase *tree = this;

    while ( tree!= NULL )
    {
        if ( tree->_down != NULL ) preorder_before_action();
        tree->preorder_action();
        if ( tree->_down!=NULL )
        {
            tree->_down->preorder();
            preorder_after_action();
        }
        tree = tree->_right;
    }
}

/* free all AST nodes in tree; apply func to each before freeing */
void
ASTBase::destroy()
{
   ASTBase* tree = this;
   while (tree) {
      if (tree->_down) tree->_down->destroy();

      ASTBase* cur = tree;
      tree = tree->_right;
      delete cur;
   }
}

/* build a tree (root child1 child2 ... NULL)
 * If root is NULL, simply make the children siblings and return ptr
 * to 1st sibling (child1).  If root is not single node, return NULL.
 *
 * Siblings that are actually siblins lists themselves are handled
 * correctly.  For example #( NULL, #( NULL, A, B, C), D) results
 * in the tree ( NULL A B C D ).
 *
 * Requires at least two parameters with the last one being NULL.  If
 * both are NULL, return NULL.
 */
ASTBase *
ASTBase::tmake(ASTBase *root, ...)
{
    va_list ap;
    register ASTBase *child, *sibling=NULL, *tail, *w;

    va_start(ap, root);

    if ( root != NULL )
        if ( root->_down != NULL ) return NULL;
    child = va_arg(ap, ASTBase *);
    while ( child != NULL )
    {
        for (w=child; w->_right!=NULL; w=w->_right) {;} /* find end of child */
        if ( sibling == NULL ) {sibling = child; tail = w;}
        else {tail->_right = child; tail = w;}
        child = va_arg(ap, ASTBase *);
    }
    if ( root==NULL ) root = sibling;
    else root->_down = sibling;
    va_end(ap);
    return root;
}

/* tree duplicate */
ASTBase *
ASTBase::dup()
{
    ASTBase *u, *t=this;

    u = new ASTBase;
    *u = *t;
    u->_right = t->_right->dup();
    u->_down = t->_down->dup();
    return u;
}

/* tree duplicate */
ASTDoublyLinkedBase *
ASTDoublyLinkedBase::dup()
{
    ASTDoublyLinkedBase *u, *t=this;

    if ( t == NULL ) return NULL;
    u = new ASTDoublyLinkedBase;
    *u = *t;
    u->_up = NULL;        /* set by calling invocation */
    u->_left = NULL;
    u->_right = t->_right->dup();
    u->_down = t->_down->dup();
    if ( u->_right!=NULL ) ((ASTDoublyLinkedBase *)u->_right)->_left = u;
    if ( u->_down!=NULL ) ((ASTDoublyLinkedBase *)u->_down)->_up = u;
    return u;
}

/*
 * Set the 'up', and 'left' pointers of all nodes in 't'.
 * Initial call is double_link(your_tree, NULL, NULL).
 */
void
ASTDoublyLinkedBase::double_link(ASTBase *left, ASTBase *up)
{
    ASTDoublyLinkedBase *t = this;

    t->_left = (ASTDoublyLinkedBase *) left;
    t->_up = (ASTDoublyLinkedBase *) up;
    ((ASTDoublyLinkedBase *)t->_down)->double_link(NULL, t);
    ((ASTDoublyLinkedBase *)t->_right)->double_link(t, up);
}