! notes:
!	arg_buff contains the arguments collected so far.
!
!	prm_buff contains the lexemes collected so far for
!	the current argument.
!
!	when tracing is on, RUND will place the lexemes
!	encoutered in trace_buff.  symbols and delimiters
!	are stored together in each lexeme word.
!
!	when the macro context changes (e.g. a macro
!	within a macro) then the trace buffer is concatenated
!	to the appropriate trace list for the current
!	macro context and trace_buff is reset.  thus there
!	is no need to push trace_buff.

Literal
	SRC_FILE	= 0,
	SRC_MACRO	= 1,
	SRC_STRUCTURE	= 2,
	SRC_MACRO_ARG	= 3,
	SRC_LEXICAL	= 4;

Literal
	SZ_MAC_INFO	= 21,
	SZ_ARG_BUFF	= 32,
	SZ_PRM_BUFF	= 32,
	SZ_TRACE_BUFF	= 32;

External
	mac_info	: Block[21],
	arg_buff	: Vector[SZ_ARG_BUFF],
	prm_buff	: Vector[SZ_PRM_BUFF],
	trace_buff	: Vector[SZ_TRACE_BUFF];

!
! notes:
!	mac_next	-> previous macro block
!
!	mac_type	source stream type (SRC_xxx)
!
!	mac_mode	macro attributes (iterative, recursive, etc)
!
!	mac_v_eos	TRUE if the end of the macro stream has been reached
!
!	mac_v_peek	TRUE if a lookahead was performed
!
!	mac_v_trace	TRUE if this macro is being traced
!
!	mac_trace1	-> stream of traced lexemes for the whole
!			macro expansion. for non-iterative macros,
!			the trace buffer is appended to this whenever
!			the mac_info block is pushed or at the end
!			of the macro.  for iterative macros, the
!			mac_trace2 list is appended to it at the
!			end of each iteration.  when the macro expansion
!			is complete this list is displayed.  if the
!			previous macro was being traced then this
!			list is appended to the previous macro's
!			trace list.  if not then this list is
!			destroyed.
!
!	mac_trace2	-> stream of traced lexemes for iterations.
!			for iterative macros, the trace buffer is
!			appended to this list. at the end of an
!			iteration, this list is displayed and then
!			append to the mac_trace1 list.
!
!	mac_iteration	interation number.  incremented each time
!			a new interation starts on an interative
!			macro. the $COUNT lexical function returns
!			this.
!
!	mac_length	total number of arguments to a macro.  the
!			$LENGTH lexical function returns this.
!
!	mac_body	-> stream of lexemes being read.
!
!	mac_body0	-> original stream of lexemes.  used
!			for resetting mac_body for the next
!			iteration.
!
!	mac_ibody	index into mac_body stream
!
!	mac_name	-> macro/structure symbol
!
!	mac_argv	-> stream of arguments to macro
!
!	mac_argv0	-> original stream of arguments.
!			used to release the argument when
!			the macro is done.
!
!	mac_argc	number of arguments left in mac_argv
!
!	mac_iarg	index into mac_argv
!
!	mac_num_actual	number of actuals consumed this
!			iteration.  for the first iteration
!			it is the number of fixed plus the
!			number of iterative arguments.  for
!			iterations thereafter it is just the
!			number of iterative arguments.
!
!	mac_actuals	-> vector of actual arguments for the
!			current iteration.
!
!	mac_delim	iteration delimiters
!				[0] = separator
!				[1] = closing delimiter
!				[2] = opening delimiter
!
!	mac_num_fixed	number of fixed arguments this macro
!			takes.
!
!	mac_num_iter	number of iterative arguments this
!			macro takes.
!
!	mac_file	for source file stream, a pointer
!			to a file context block.
!
!	mac_index	index into mac_stack.
!
!	mac_stack	stack of future lexemes.  whenever
!			a file or stream take is performed,
!			the atom taken is placed on this stack.
!			iteration delimiters and lexical function
!			expansions are also placed on this stack.

Bind
	mac_next	= MAC_INFO[ 0, 0,64,1]	: Ref Block,

    	mac_type	= MAC_INFO[ 1, 0, 8,0]	: Byte,
	mac_mode	= MAC_INFO[ 1, 8, 8,0]	: Byte,
	mac_num_fixed	= MAC_INFO[ 1,16, 8,0]	: Byte,
	mac_num_iter	= MAC_INFO[ 1,24, 8,0]	: Byte,
	mac_num_actual	= MAC_INFO[ 1,32, 8,0]	: Byte,
	mac_v_eos	= MAC_INFO[ 1,40, 8,0]	: Byte,
	mac_v_peek	= MAC_INFO[ 1,48, 8,0]	: Byte,
	mac_v_trace	= MAC_INFO[ 1,56, 8,0]	: Byte,

	mac_name	= MAC_INFO[ 2, 0,64,1]	: Ref ST,
	mac_actuals	= MAC_INFO[ 3, 0,64,1]	: Ref Vector,

	mac_body	= MAC_INFO[ 4, 0,64,1]	: Ref Vector,
	mac_body0	= MAC_INFO[ 5, 0,64,1]	: Ref Vector,
	mac_ibody	= MAC_INFO[ 6, 0,64,1]	: Integer,

	mac_argv	= MAC_INFO[ 7, 0,64,1]	: Ref Vector,
	mac_argv0	= MAC_INFO[ 8, 0,64,1]	: Ref Vector,
	mac_argc	= MAC_INFO[ 9, 0,64,1]	: Integer,
	mac_iarg	= MAC_INFO[10, 0,64,1]	: Integer,

	mac_trace1	= MAC_INFO[11, 0,64,1]	: Ref Vector,
	mac_trace2	= MAC_INFO[12, 0,64,1]	: Ref Vector,

	mac_iteration	= MAC_INFO[13, 0,64,1]	: Integer,
	mac_length	= MAC_INFO[14, 0,64,1]	: Integer,

	mac_delim	= MAC_INFO[15, 0,64,1]	: Vector[4,Byte],

	mac_index	= MAC_INFO[16, 0,64,1]	: Integer,
	mac_stack	= MAC_INFO[17, 0,64,1]	: Vector[4],

	mac_file	= MAC_INFO[ 2, 0,64,1];