/* xleval - evaluate an xlisp expression (checking for *evalhook*) */
LVAL xleval(LVAL expr)
{
/* check for control codes */
if (--xlsample <= 0) {
xlsample = SAMPLE;
oscheck();
}
/* check for *evalhook* */
if (getvalue(s_evalhook))
return (evalhook(expr));
/* check for nil */
if (null(expr))
return (NIL);
/* dispatch on the node type */
switch (ntype(expr)) {
case CONS:
return (evform(expr));
case SYMBOL:
return (xlgetvalue(expr));
default:
return (expr);
}
}
/* xleval - evaluate an xlisp expression (checking for *evalhook*) */
NODE *xleval(NODE *expr)
{
/* check for control codes */
if (--xlsample <= 0) {
xlsample = SAMPLE;
oscheck();
}
/* check for *evalhook* */
if (getvalue(s_evalhook))
return (evalhook(expr));
/* add trace entry */
if (++xltrace < TDEPTH)
trace_stack[xltrace] = expr;
/* check type of value */
if (consp(expr))
expr = evform(expr);
else if (symbolp(expr))
expr = xlgetvalue(expr);
/* remove trace entry */
--xltrace;
/* return the value */
return (expr);
}
/* xlxeval - evaluate an xlisp expression (bypassing *evalhook*) */
NODE *xlxeval(NODE *expr)
{
/* check type of value */
if (consp(expr))
expr = evform(expr);
else if (symbolp(expr))
expr = xlgetvalue(expr);
/* return the value */
return (expr);
}
/* xlxeval - evaluate an xlisp expression (bypassing *evalhook*) */
LVAL xlxeval(LVAL expr)
{
/* check for nil */
if (null(expr))
return (NIL);
/* dispatch on node type */
switch (ntype(expr)) {
case CONS:
return (evform(expr));
case SYMBOL:
return (xlgetvalue(expr));
default:
return (expr);
}
}
