diff options
Diffstat (limited to 'Master/texmf-dist/doc/plain/impatient/concepts.tex')
-rw-r--r-- | Master/texmf-dist/doc/plain/impatient/concepts.tex | 26 |
1 files changed, 14 insertions, 12 deletions
diff --git a/Master/texmf-dist/doc/plain/impatient/concepts.tex b/Master/texmf-dist/doc/plain/impatient/concepts.tex index 2b386753455..ac53a019904 100644 --- a/Master/texmf-dist/doc/plain/impatient/concepts.tex +++ b/Master/texmf-dist/doc/plain/impatient/concepts.tex @@ -1,5 +1,6 @@ +% $Id: concepts.tex,v 1.5 2020/01/01 23:55:26 karl Exp $ % This is part of the book TeX for the Impatient. -% Copyright (C) 2003, 2014 Paul W. Abrahams, Kathryn A. Hargreaves, Karl Berry. +% Copyright (C) 2003-2020 Paul W. Abrahams, Kathryn A. Hargreaves, Karl Berry. % See file fdl.tex for copying conditions. \input macros @@ -755,7 +756,7 @@ is an instruction to \TeX\ to produce a certain character in a certain (the usual escape character) is $92$. If you type `|\char92 grok|', it is \emph{not} equivalent to |\grok|. Instead it tells \TeX\ to -typeset `$c$grok', where $c$ is the character in position $92$ +typeset `$c$\kern.075em grok', where $c$ is the character in position $92$ of the code table for the current font. You can use the ^|\catcode| command \ctsref{\catcode} to reassign the @@ -765,10 +766,11 @@ change the roles of various characters. For instance, if you type to ``letter''. You then can use `|@|' in the name of a control sequence. -Here is a list of the category codes as they're defined in -\refterm{\plainTeX} (see \xref{twocarets} for an explanation of +Here is a list of the category codes defined by \TeX, +(see \xref{twocarets} for an explanation of the |^^| notation), -together with the characters in each category: +together with the characters in each category (as assigned +by \TeX\ and \refterm{\plainTeX}): \xrdef{catcodes} \vskip\abovedisplayskip @@ -841,8 +843,7 @@ is a valid group, and so are \hbox{`|[a b}|'} and~\hbox{`|{a b]|'}. The characters in categories $11$ (letter) and $12$ (other character) act as \refterm{commands:command} that mean -``produce a \refterm{box} containing this character -typeset in the current font''. +``typeset the character with this code from the current font''. The only distinction between letters and ``other'' characters is that letters can appear in \refterm{control word}s but ``other'' characters~can't. @@ -874,7 +875,7 @@ code until its \emph{second} look at the character. For example: \csdisplay \def\foo{\catcode`\$ = 11 }% Make $ be a letter. \foo$ % Produces a `$'. -\foo$ % Undefined control sequence `foo$'. +\foo$ % Undefined control sequence `\foo$'. | \noindent This bit of \TeX\ code produces `\$' in the typeset output. When @@ -968,11 +969,12 @@ notation you'll find it handy to have a table of \ascii\ codes. An output character is a character to be typeset. A command for producing an output character has the meaning -``Produce a \refterm{box} containing +``Typeset character number $n$ from the current \refterm{font}'', where $n$ is determined by the command. -\TeX\ produces your typeset document by combining such boxes with -other typographical \hbox{elements} and arranging them +\TeX\ produces your typeset document by combining such characters +with +other typographical \hbox{elements} in boxes, and arranging them on the page. An input character whose category code is $11$ (^{letter}) or $12$ (other) @@ -992,7 +994,7 @@ command `|\char |$n$' \ctsref{\char}, ^^|\char| where $n$ is a The \defterm{class} of a \refterm{character} specifies that character's role in math formulas. The class of a character is encoded in its \refterm{mathcode}. ^^{mathcodes//class encoded in} For example, the -equals sign `|=|' is in class $3$ (Relation). \TeX\ uses its knowledge +equals sign `|=|' has class $3$ (Relation). \TeX\ uses its knowledge of character classes to decide how much space to put between different components of a math formula. \margin{clarifying material added} For example, here's a math formula shown first as \TeX\ normally prints it |