B></PRE>Return the list of variables (as integers) in a trail.  Note that this
ignores the contexts associated with the varibles.
<HR><A NAME=defns></A><H2>Public Definitions in File unify.h</H2>
<PRE>
/* Dereference a variable. */

#define DEREFERENCE(t, c) { int i; \
    while (c!=NULL && VARIABLE(t) && c->terms[i=VARNUM(t)]) \
    { t = c->terms[i]; c = c->contexts[i]; } } 

/* A <A HREF="unify.html">Context</A> records a substitution of terms for variables. */

typedef struct context * <A HREF="unify.ht