{
{   The purpose of this request is to isolate an SCL command within TEXT.  The
{ command is assumed to begin in TEXT at START_INDEX.  This request returns in
{ END_INDEX the index of the character that follows the command.  Thus
{ END_INDEX is normally returned as strlength(text)+1, but when more than one
{ command appears on a line END_INDEX designates the command separator (e.g.  a
{ semicolon).
{
{       CLP$ISOLATE_COMMAND (TEXT, START_INDEX, END_INDEX)
{
{ TEXT: (input)  This parameter specifies the text to be scanned.
{
{ START_INDEX: (input)  This parameter specifies the first character within
{       TEXT to be scanned.
{
{ END_INDEX: (output)  This parameter specifies the index of the character
{       following the command.
{
