THE 'MERGE A LINE OR A VARIABLE' SUBROUTINE

This subroutine is entered with the following parameters:
	Carry flag	reset	- MERGE a BASIC line.
		set	- MERGE a variable.
	Zero		reset	- It will be an 'addition'.
			set	- It is a 'replacement'.
	HL register pair		- Points to the start of the new entry.
	DE register pair		- Points to where it is to MERGE.

092C	ME-ENTER	JR	NZ,093E,ME-ENT-1	Jump if handling an 'addition'.
		EX	AF,A'F'	Save the flags.
		LD	(X-PTR),HL	Save the 'new' pointer whilst
		EX	DE,HL	the 'old' line or variable
		CALL	19B8,NEXT-ONE	is reclaimed.
		CALL	19E8,RECLAIM-2
		EX	DE,HL
		LD	HL,(X-PTR)
		EX	AF,A'F'	Restore the flags.

The new entry can now be made.

093E	ME-ENT-1	EX	AF,A'F'	Save the flags.
		PUSH	DE	Make a copy of the
				'destination' pointer.
		CALL	19B8,NEXT-ONE	Find the length of the 'new'
				variable/line.
		LD	(X-PTR),HL	Save the pointer to the 'new'
				variable/line.
		LD	HL,(PROG)	Fetch PROG - to avoid
				corruption.
		EX	(SP),HL	Save PROG on the stack and
				fetch the 'new' pointer.
		PUSH	BC	Save the length.
		EX	AF,A'F'	Retrieve the flags.
		JR	C,0955,ME-ENT-2	Jump forward if adding a new
				variable.
		DEC	HL	A new line is added before the
				'destination' location.
		CALL	1655,MAKE-ROOM	Make the room for the new line.
		INC	HL
		JR	0958,ME-ENT-3	Jump forward.
0955	ME-ENT-2	CALL	1655,MAKE-ROOM	Make the room for the new
				variable.
0958	ME-ENT-3	INC	HL	Point to the l st new location.
		POP	BC	Retrieve the length.
		POP	DE	Retrieve PROG and store it
		LD	(PROG),DE	in its correct place.
		LD	DE,(X-PTR)	Also fetch the 'new' pointer.
		PUSH	BC	Again save the length and the
		PUSH	DE	new' pointer.
		EX	DE,HL	Switch the pointers and copy
		LDIR		the 'new' variable/line into the
				room made for it.

The 'new' variable/line has now to be removed from the work space.

		POP	HL	Fetch the 'new' pointer.
		POP	BC	Fetch the length.
		PUSH	DE	Save the 'old' pointer. (Points
				to the location after the 'added'
				variable/line.)
		CALL	19E8,RECLAIM-2	Remove the variable/line from
				the work space.
		POP	DE	Return with the 'old' pointer
		RET		in the DE register pair.