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1%D \module
2%D   [       file=catc-act,
3%D        version=2006.09.18,
4%D          title=\CONTEXT\ Catcode Macros,
5%D       subtitle=Default Catcode Tables,
6%D         author=Hans Hagen,
7%D           date=\currentdate,
8%D      copyright={PRAGMA ADE \& \CONTEXT\ Development Team}]
9%C
10%C This module is part of the \CONTEXT\ macro||package and is
11%C therefore copyrighted by \PRAGMA. See mreadme.pdf for
12%C details.
13
14%D This module deals with some active character handling. Use
15%D with care.
16
17\unprotect
18
19% todo: \letcharcode<number>=\something
20
21%D \macros
22%D   {installactivecharacter}
23
24\let\m_syst_catcodes_temp\empty
25
26\protected\def\installactivecharacter#1 %
27  {\edef\m_syst_catcodes_temp{\detokenize{#1}}%
28   \c_syst_catcodes_c\expandafter`\m_syst_catcodes_temp\relax % relax needed
29   \expandafter\startextendcatcodetable
30      \expandafter\ctxcatcodes\expandafter\catcode\the\c_syst_catcodes_c\activecatcode
31   \stopextendcatcodetable
32   \letcatcodecommand \ctxcatcodes \c_syst_catcodes_c \m_syst_catcodes_temp \relax
33   \ifnum\currentcatcodetable=\ctxcatcodes \setcatcodetable\ctxcatcodes \fi
34   \let\m_syst_catcodes_temp\empty}
35
36%D \macros
37%D   {defineactivecharacter}
38%D
39%D Use this one with care, esp in combination with catcode
40%D vectors. There are better ways now.
41
42\setnewconstant\c_syst_catcodes_hack\tildeasciicode % also defined in catc-ini.mkiv
43
44\protected\def\defineactivecharacter #1#2 #3% uses \doifelsenumber which is not yet defined
45  {\c_syst_catcodes_c\uccode\c_syst_catcodes_hack
46   \if#1"\uccode\c_syst_catcodes_hack\expandafter\doifelsenumber\expandafter{\string#1#2}\empty #1#2\else
47         \uccode\c_syst_catcodes_hack\expandafter\doifelsenumber\expandafter{\string#1#2}\empty`#1#2\fi
48   \catcode\uccode\c_syst_catcodes_hack\activecatcode
49   \uppercase{\def\m_syst_catcodes_temp{~}}% brrr
50   \uccode\c_syst_catcodes_hack\c_syst_catcodes_c
51   \expandafter\expandafter\expandafter\def\expandafter\m_syst_catcodes_temp\expandafter
52     {\expandafter\syst_catcodes_handle\m_syst_catcodes_temp{#3}}%
53   \let\m_syst_catcodes_temp\empty}
54
55\chardef\activecharactermode\plusone % overloading still backward compatible
56
57\def\syst_catcodes_handle
58  {\ifcase\activecharactermode
59     \expandafter\syst_catcodes_handle_nop
60   \else
61     \expandafter\syst_catcodes_handle_yes
62   \fi}
63
64\def\syst_catcodes_handle_yes#1#2{#2}
65\def\syst_catcodes_handle_nop#1#2{\noexpand#1}
66
67\protected\def\makecharacteractive #1 %
68  {\catcode`#1\activecatcode}
69
70\protected\def\installanddefineactivecharacter #1 % #2%
71  {\normalexpanded{\noexpand\installactivecharacter \utfchar{#1} }%
72   \defineactivecharacter #1 }% {#2}}
73
74\protect \endinput
75