[Copyright status: This file is in the public domain.]

level file format:

(except as noted, whitespace may appear anywhere).

level-file	:	nothing
		|	level level-file
		;

level		:	level-name level-contents
		;

level-name	:	name-length nonblank-char name-string
		;
	name-length is a number in decimal, containing no whitespace
	nonblank-char is any non-whitespace, non-digit character
	the name-string is the first name-length characters after,
	  but not including, the nonblank-char

level-contents	:	BOARD_Y "row"s
		;

row		:	BOARD_X "cell"s
		;

cell		:
	one of the following character pairs, whitespace not allowed
	  within the pair, permitted but not required between pairs
	__	blank
	QB	blue square
	QY	yellow square
	RB	blue ring
	RY	yellow ring
	PB	blue plus
	PY	yellow plus
	DB	blue diamond
	DY	yellow diamond
	CB	blue colorizer
	CY	yellow colorizer
	CF	flip colorizer
	WL	(immovable) wall
	MW	movable wall
	TL	teleporter
	MU	mutator
	PL	player
	SA	\
	SB	 |
	SC	 |
	SD	 |
	SE	  \ various
	SF	  / starfields
	SG	 |
	SH	 |
	SI	 |
	SJ	/