infocom/compilers/inform6/library/contributions/AskTellOrder.h

! AskTellOrder by Irene Callaci (icallaci@csupomona.edu)
!
! The BeforeParsing() routine included below reparses the player's input,
! converting:
!
!		ASK/TELL THE NPC TO DO SOMETHING
! into
!		NPC, DO SOMETHING
!
! so that your NPC's orders routine can handle it. No modification to the
! grammar for ASK or TELL is required.
!
! BeforeParsing() is an Inform entrypoint, so include it after Verblib but
! before Grammar.
!
!	Irene Callaci	 -	icallaci@csupomona.edu
!	March 12, 1999
!
! Updates:
! 1. Added a switch to allow ASK NPC ABOUT <topic>, where <topic> includes the word 'to',
!    such as ASK COP ABOUT WITNESSES TO THE ACCIDENT -- January 5, 2000
! 2. Truncate input before retokenising -- January 5, 2000
! ---------------------------------------------------------------------------

[ BeforeParsing i j k w skip inc;
	i = 0; j = 0; k = 0; w = 0; skip = 0; inc = 0;

	! Find verb_wordnum (usually 1, but not when the command is NPC, VERB THE <OBJECT>)
	for (i = 2 : i <= num_words : i++)
	{	w = NextWord();
		if (w == comma_word) break;
	}
	if (wn >= num_words) wn = 1;

	for (i = parse->2, j = 2 : j < i : j++)
	{	w = NextWord();
		switch (w)
		{	'ask', 'tell':
				! First, count any blank spaces at the beginning of input
				for (i = 2 : i < buffer->1 : i++)
				{	if (buffer->i == ' ') skip++;
					else break;
				}

				! Next, count the number of letters in the first word (ASK or TELL)
				skip = skip + WordLength(wn - 1) + 1;

				! Now get the next word. If it's an article, count the number of
				! letters it contains so we can overwrite it later. If we don't do
				! this, we end up with invalid input like: THE NPC, VERB
				w = NextWord();
				if (w == 'a//' or 'an' or 'the')
				{	skip = skip + WordLength(wn - 1) + 1;
					w = NextWord();
				}

				! Now we've reached a likely spot for the NPC's name. Because NPCs can
				! have more than one name (CHARLIE SMITH, for example), we loop until
				! we find the word "to" or some other word that signals the start of
				! the actual command.
				while (w ~= 0)
				{	! We need to know how long the NPC name is so that we can skip over
					! it later without overwriting it.
					inc = inc + WordLength(wn - 1) + 1;
					w = NextWord();
					switch (w)
					{	'about':
							! Stop reparsing here to avoid problems with ASK COP ABOUT WITNESSES TO THE ACCIDENT (otherwise, the 'to' below will trigger an NPC order)
							rfalse;
						'to':
							! Find the word "to" in the input and replace it with a
							! comma followed by a blank (to erase the "o").
							for (i = skip + inc + 1 : i <= (buffer->1) + 1 : i++)
							{	if (buffer->i == ' ' && buffer->(i+1) == 84 or 116 && buffer->(i+2) == 79 or 111 && buffer->(i+3) == ' ')
								{	buffer->(i+1) = 44;		! ascii code for comma
									buffer->(i+2) = ' ';
									break;
								}
							}

							! Move the NPC's name and everything following it to the
							! left, overwriting as we go.
							for (i = 2 : i <= (buffer->1) + 1 : i++)
								buffer->i = buffer->(i + skip);

							! Truncate the command and retokenise the input.
							buffer->1 = (buffer->1) - skip;
							Tokenise__(buffer, parse);
					}
				}
			default:
				rfalse;
		}
		break;
	}
];