[tex-k] Errors in Chapter 27 of The METAFONTbook

胡亚捷 (Hu Yajie) 2500418497 at qq.com
Fri Jun 19 08:51:57 CEST 2020

Chapter 27 `Recovery from Errors' of The METAFONTbook has some errors itself.

Page C224, line 9
There should be three spaces between `<insert>' and `mode_setup' in METAFONT's
response to `I mode_setup'. The first space is inherent after the `<insert>'
in section 637 of Volume D; the remaining two comes from the buffer because
section 82 simply sets the `I' to a space in `I mode_setup' before inserting.
(The space in `I mode_setup' on the previous page is very thin, but mfbook.tex
and exercise 5.4 confirm it. You do get two spaces with `Imode_setup' though.)

Page C224, lines -10 to -7
The fractional part of `259.0005' should be `.00049' (twice) as it comes from
the `eps' added by define_corrected_pixels. In addition, the four dependencies
would be printed in reverse order by METAFONT. Since the `new_dep' procedure
in section 606 inserts new dependency lists in front of the existing ones, and
`do_show_dependencies' in section 1050 prints the list from the head, the
latest ones come first. The book instead gives the logical order as with `##'.
(Will Knuth fix the second bug by changing the book or changing the program?:)

Page C228, line -9
What is this `p.4'? I didn't find any code in Volume D that can print it.

Earlier reports:

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