Forest At World's End: Routine at 49112

49112: Parser: Match Input Word

Split the command into words and look each one up in the vocabulary.
Blank the four-character word buffer.
Parser_MatchInputWord	49112	LD DE,47937	Start at the word buffer (47937).
	49115	LD B,4	Prepare a space and a counter of 4 characters.
	49117	LD A,32	Prepare a space and a counter of 4 characters.
MatchInputWord_Clear	49119	LD (DE),A	Write spaces through the word buffer.
	49120	INC DE
	49121	DJNZ MatchInputWord_Clear
	49123	XOR A	Jump to Handler_UnknownWord when no token slots remain, or the command has ended.
	49124	OR C
	49125	JP Z,Handler_UnknownWord
	49128	LD A,(HL)
	49129	CP 13
	49131	JP Z,Handler_UnknownWord
Copy the next word, up to 4 characters, stopping at a space, a comma or ENTER.
	49134	LD B,4	Copy up to 4 characters into the word buffer.
	49136	LD DE,47937	Copy up to 4 characters into the word buffer.
MatchInputWord_Copy	49139	LD A,(HL)	Jump to MatchInputWord_IgnoreThe when the character is ENTER.
	49140	CP 13
	49142	JR Z,MatchInputWord_IgnoreThe
	49144	CP 32	Jump to MatchInputWord_Delimiter when the character is a space or a comma.
	49146	JR Z,MatchInputWord_Delimiter
	49148	CP 44
	49150	JR Z,MatchInputWord_Delimiter
	49152	LD (DE),A	Copy the character into the word buffer and advance both pointers.
	49153	INC HL
	49154	INC DE
	49155	DJNZ MatchInputWord_Copy	Repeat from MatchInputWord_Copy until four characters have been copied.
A longer word is skipped up to the next delimiter.
MatchInputWord_Skip	49157	LD A,(HL)	Jump to MatchInputWord_IgnoreThe on ENTER, or to MatchInputWord_Delimiter on a space or a comma.
	49158	CP 13
	49160	JR Z,MatchInputWord_IgnoreThe
	49162	CP 32
	49164	JR Z,MatchInputWord_Delimiter
	49166	CP 44
	49168	JR Z,MatchInputWord_Delimiter
	49170	INC HL	Skip this character and keep looking for a delimiter.
	49171	JR MatchInputWord_Skip	Skip this character and keep looking for a delimiter.
MatchInputWord_Delimiter	49173	INC HL	Skip consecutive spaces and commas.
	49174	LD A,(HL)
	49175	CP 32
	49177	JR Z,MatchInputWord_Delimiter
	49179	CP 44
	49181	JR Z,MatchInputWord_Delimiter
Ignore the word "THE ".
MatchInputWord_IgnoreThe	49183	EXX	Switch in the spare registers and point them at "THE " and the word.
	49184	LD HL,47964
	49187	LD DE,47937
	49190	LD B,4
MatchInputWord_The	49192	LD A,(DE)	Compare the four characters.
	49193	CP (HL)
	49194	JR NZ,MatchInputWord_AfterThe
	49196	INC DE
	49197	INC HL
	49198	DJNZ MatchInputWord_The
MatchInputWord_AfterThe	49200	EXX	Switch back to the main registers to act on the comparison.
	49201	JR Z,Parser_MatchInputWord	Jump back to Parser_MatchInputWord when the word was THE, so it is not tokenised.
	49203	DEC C	Use up one token slot.
	49204	EXX	Use up one token slot.
Look the word up in the vocabulary. A comma separates synonyms.
	49205	LD HL,(47836)	Start at the vocabulary, with the token index at zero.
	49208	LD C,0	Start at the vocabulary, with the token index at zero.
MatchInputWord_Vocabulary	49210	LD A,(HL)	Jump to MatchInputWord_Unknown when the vocabulary is exhausted.
	49211	CP 255
	49213	JR Z,MatchInputWord_Unknown
MatchInputWord_CompareWord	49215	LD DE,47937	Compare the next vocabulary word with the word buffer.
	49218	LD B,4	Compare the next vocabulary word with the word buffer.
MatchInputWord_CompareChar	49220	LD A,(DE)	Compare the next character.
	49221	CP (HL)	Compare the next character.
	49222	JR NZ,MatchInputWord_NextWord	Jump to MatchInputWord_NextWord when it does not match.
	49224	INC DE
	49225	INC HL
	49226	DJNZ MatchInputWord_CompareChar
	49228	EXX	Turn the vocabulary index into a token-slot offset.
	49229	LD A,9
	49231	SUB C
	49232	EXX
	49233	LD D,0
	49235	LD E,A
	49236	LD HL,47926	Store that token in its slot at 47926 and parse the next word.
	49239	ADD HL,DE
	49240	LD (HL),C
	49241	EXX
	49242	JP Parser_MatchInputWord
MatchInputWord_NextWord	49245	LD E,B	Step to the end of this vocabulary word.
	49246	LD D,0
	49248	ADD HL,DE
	49249	LD A,(HL)	Jump back to MatchInputWord_CompareWord to try the synonym after a comma.
	49250	CP 44
	49252	JR NZ,MatchInputWord_NextEntry
	49254	INC HL
	49255	JR MatchInputWord_CompareWord
MatchInputWord_NextEntry	49257	INC C	Try the next vocabulary word.
	49258	JR MatchInputWord_Vocabulary	Try the next vocabulary word.
The word is not in the vocabulary, so quote it and ask again.
MatchInputWord_Unknown	49260	EXX	Find the unknown word in the command buffer.
	49261	LD A,10
	49263	SUB C
	49264	LD C,A
	49265	LD HL,47876
MatchInputWord_SeekWord	49268	DEC C	Step back through the copied word count.
	49269	JR Z,MatchInputWord_PrintUnknown	Step back through the copied word count.
MatchInputWord_FindWord	49271	LD A,(HL)	Skip characters until a space or a comma.
	49272	CP 32
	49274	JR Z,MatchInputWord_FindDelimiter
	49276	CP 44
	49278	JR Z,MatchInputWord_FindDelimiter
	49280	INC HL
	49281	JR MatchInputWord_FindWord
MatchInputWord_FindDelimiter	49283	INC HL	Skip spaces and commas, then look for the next word.
	49284	LD A,(HL)
	49285	CP 32
	49287	JR Z,MatchInputWord_FindDelimiter
	49289	CP 44
	49291	JR Z,MatchInputWord_FindDelimiter
	49293	JR MatchInputWord_SeekWord
MatchInputWord_PrintUnknown	49295	PUSH HL	Print "I don't know the word:-".
	49296	LD HL,47989
	49299	CALL PrintStringAndANewline
	49302	POP HL	Restore the command pointer from the stack.
	49303	LD A,34	Print a quote.
	49305	CALL PrintCharacter	Print a quote.
MatchInputWord_Quote	49308	LD A,(HL)	Print the unknown word up to the next space.
	49309	CP 33
	49311	JR C,MatchInputWord_CloseQuote
	49313	INC HL
	49314	CALL PrintCharacter
	49317	JR MatchInputWord_Quote
MatchInputWord_CloseQuote	49319	LD A,34	Print a closing quote.
	49321	CALL PrintCharacter	Print a closing quote.
	49324	LD HL,48377	Print "." and read another command.
	49327	CALL PrintStringAndANewline
	49330	JR Handler_UnknownWord_Retry
View the equivalent code in; Heroes Of Karn Message From Andromeda The Jewels Of Babylon