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Markdown fixes for README. Cat's Eye Technologies 11 years ago

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0	0	Zzrk - Adventures in the Great Unsaturated Grammar
1		====
	1	==================================================
2	2
3	3	What is it?
4	4	-----------

21	21
22	22	First, you need an implementation of Zz. The only one I've found, and
23	23	subsequently the one I've written Zzrk around, is OpenZz. It can be
24		gotten from http://openzz.sourceforge.net/.
	24	gotten from [http://openzz.sourceforge.net/](http://openzz.sourceforge.net/).
25	25
26	26	Although OpenZz does have an interactive mode, it unfortunately assumes
27	27	you're using Zz to describe a compiler. Since I assume you'll want to

30	30	happens), here's a guide to working around some of OpenZz's drawbacks.
31	31
32	32	First, you can't just specify zzrk.zz as the input to ozz. Instead,
33		start OpenZz, then at the "ozz>" prompt, type
	33	start OpenZz, then at the `ozz>` prompt, type
34	34
35	35	/include "zzrk.zz"
36	36
37		You can then treat the "ozz>" prompt as the prompt for the adventure
	37	You can then treat the `ozz>` prompt as the prompt for the adventure
38	38	game parser. Try the usual actions, and see what happens. Be forewarned
39	39	that any unrecognizable command on your part -- an unknown verb, noun, or
40	40	other part of speech -- will trigger a syntax error. And, because OpenZz

49	49	puzzles just to demonstrate that the standard adventure game furniture can
50	50	be concocted in Zz. Collecting treasures will get you points, and
51	51	obtaining 50 points will win the game (that is, if you have 50 points and
52		you type "score", you will get a message telling you that you have won.
	52	you type `score`, you will get a message telling you that you have won.
53	53	You will still need to quit OpenZz through some other manual action, such
54	54	as typing Ctrl-D, or causing syntax errors.)
55	55

57	57	Comments
58	58	--------
59	59
60		I originally wrote zzrk.zz on November 21st, 2003. I gave it actual
	60	I originally wrote `zzrk.zz` on November 21st, 2003. I gave it actual
61	61	puzzles, wrote this readme, and released it under a BSD license on
62	62	May 6, 2007.
63	63
64	64	A couple of annoying things about Zz...
65	65
66		The documentation for OpenZz doesn't mention that the /if { } construct
67		has a variant that takes an else clause. And, /return does not actually
	66	The documentation for OpenZz doesn't mention that the `/if { }` construct
	67	has a variant that takes an `else` clause. And, `/return` does not actually
68	68	cause an immediate return, it only assigns a value to the nonterminal
69	69	under consideration. For these reasons, I was originally writing many of
70		my tests twice (like /if a == b {} /if a != b {}). Then I noticed, in
71		examining the results of /krules, that the kernel does in fact support
72		else. The fact that curly braces actually denote lists means they're not
	70	my tests twice (like `/if a == b {} /if a != b {}`). Then I noticed, in
	71	examining the results of `/krules`, that the kernel does in fact support
	72	`else`. The fact that curly braces actually denote lists means they're not
73	73	optional in tests though, and the nesting is still pretty annoying.
74	74
75	75	The other annoying thing is that there's no way to prioritize selection
76	76	of nonterminals. For example, I feel very strongly that it ought to be
77		possible to write the score_of production like this:
	77	possible to write the `score_of` production like this:
78	78
79		/$num_t -> "score_of" coin { /return 5 }
80		/$num_t -> "score_of" jewel { /return 10 }
81		/$num_t -> "score_of" sceptre { /return 15 }
82		/$num_t -> "score_of" crown { /return 20 }
83		/$num_t -> "score_of" object^$ { /return 0 }
	79	/$num_t -> "score_of" coin { /return 5 }
	80	/$num_t -> "score_of" jewel { /return 10 }
	81	/$num_t -> "score_of" sceptre { /return 15 }
	82	/$num_t -> "score_of" crown { /return 20 }
	83	/$num_t -> "score_of" object^$ { /return 0 }
84	84
85		On the basis that coin et al. are more specific than object^$, and should
	85	On the basis that `coin` et al. are more specific than `object^$`, and should
86	86	be selected before it. But, it's not possible to set this up, at least as
87	87	far as I can see. Which is a pity, because this sort of "catch-all"
88	88	mechanism would also enable much better error handling.

101	101	magic word is, you can't even use it without causing a syntax error.
102	102	But afterward it is a full-fledged part of the parser's vocabulary.
103	103	Note also that this is how the properties of an object are updated:
104		the production which handles "e_exit square_room" is replaced by one
	104	the production which handles `e_exit square_room` is replaced by one
105	105	that returns a different value, once the door is open.
106	106
107	107	Some of the action productions are a bit clumsy because they contain
108	108	logic that should probably be associated with the object instead.
109	109	Putting lists of statements in a property of the object, and using
110		Zz's /execute facility, would probably allow a "method-like" style
	110	Zz's `/execute` facility, would probably allow a "method-like" style
111	111	that permits this, but I haven't played with it.
112	112
113	113	Lastly, it's interesting to note that internal helper functions (not

128	128
129	129	Happy adventuring!
130	130
131		-Chris Pressey
132		May 6, 2007
	131	-Chris Pressey
	132	May 6, 2007
133	133	Vancouver, BC