COMMENT ⊗   VALID 00004 PAGES
C REC  PAGE   DESCRIPTION
C00001 00001
C00002 00002	%\read16 to\pagenumber
C00003 00003	\ninepoint
C00005 00004	% now we print the answers, if any
C00006 ENDMK
C⊗;
%\read16 to\pagenumber
\input manmac
\tenpoint
\pageno=800
%\pageno=\pagenumber
\def\rhead{Experimental Pages for The \TeX book}
\def\chapno{ X}
{\catcode`\%=12 \immediate\write\ans{% Answers for galley proofs:}}
\ninepoint
\subsection Syntax checking. Suppose you want to run a manuscript through
\TeX\ just to check for errors, without getting any output. Is there a
way to make \TeX\ run significantly faster while doing this? Yes; here's how:
(1)~Say `|\font|↑|\dummy||=dummy|'\kern1pt; your system should include a
file |dummy.tfm| that defines a font with no characters (but with
enough |\fontdimen| parameters to qualify as a math symbol font).
(2)~Set all the font identifiers you are using equal to |\dummy|. For
example, |\let\tenrm=\dummy|, |\let\tenbf=\dummy|, \dots, |\textfont0=\dummy|,
etc. (3)~Say `|\dummy|' to select the dummy font (since plain \TeX\ may
have selected the real |\tenrm|).  (4)~Set ↑|\tracinglostchars||=0|, so that
\TeX\ won't complain when characters aren't present in the dummy font. (5)~Set
% now we print the answers, if any

% that blank line will stop an unfinished \answer
\immediate\closeout\ans
\vfill\eject
\ninepoint
\input answers
\bye