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1%D \module
2%D   [       file=spac-fil,
3%D        version=2013.01.13,
4%D          title=\CONTEXT\ Spacing Macros,
5%D       subtitle=Fillers,
6%D         author={Hans Hagen and Wolfgang Schuster},
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\writestatus{loading}{ConTeXt Spacing Macros / Fillers}
15
16\unprotect
17
18%D A bit more extensive variant of a prototype posted by Wolfgang to the
19%D development list. Instead of dealing with a few leader types it makes
20%D sense to support them all as well as simple rule fillers. Eventually we
21%D can also use in for the mathfillers. We distinguish between alternatives
22%D and with them methods, and a checker is provided for use in applying
23%D e.g.\ fillers in lists.
24
25\installcorenamespace{filler}
26\installcorenamespace{filleralternative}
27\installcorenamespace{fillerleadermethod}
28
29\installcommandhandler \??filler {filler} \??filler
30
31\let\setupfillers\setupfiller
32
33\unexpanded\def\filler
34  {\dosingleempty\spac_fillers_indeed}
35
36\unexpanded\def\checkedfiller#1%
37  {\ifcsname\namedfillerhash{#1}\s!parent\endcsname
38     \spac_fillers_indeed[#1]%
39     \expandafter\gobbleoneargument
40   \else
41     \expandafter\firstofoneargument
42   \fi{#1}}
43
44\def\spac_fillers_indeed[#1]%
45  {\removeunwantedspaces
46   \begingroup
47   \edef\currentfiller{#1}%
48   \usefillerstyleandcolor\c!style\c!color
49   \scratchdimen\fillerparameter\c!leftmargin\relax
50   \ifzeropt\scratchdimen\else
51     \hskip\scratchdimen
52   \fi
53   \fillerparameter\c!left\relax
54   \expandnamespaceparameter\??filleralternative\fillerparameter\c!alternative\s!unknown\relax
55   \fillerparameter\c!right\relax
56   \scratchdimen\fillerparameter\c!rightmargin\relax
57   \ifzeropt\scratchdimen\else
58     \hskip\scratchdimen
59   \fi
60   \endgroup
61   \ignorespaces}
62
63% \definefiller
64%   [MyFiller]
65%   [offset=.25\emwidth,
66%    rightmargindistance=-\rightskip,
67%    method=middle]
68%
69% \startitemize[packed,joinedup][rightmargin=5em]
70%     \startitem
71%         \input sapolsky \fillupto[MyFiller]{RS}
72%     \stopitem
73% \stopitemize
74
75\unexpanded\def\fillupto
76  {\dosingleempty\spac_fillers_upto}
77
78\def\spac_fillers_upto[#1]#2%
79  {\removeunwantedspaces
80   \begingroup
81   \edef\currentfiller{#1}%
82   \scratchdimen\dimexpr\fillerparameter\c!rightmargindistance\relax
83   \ifzeropt\scratchdimen\else
84     \parfillskip \scratchdimen\s!plus \plusone\s!fil\relax
85   \fi
86   \spac_fillers_indeed[#1]%
87   \doifsomething{#2}{\hbox{#2}}%
88   \par
89   \endgroup
90   \ignorespaces}
91
92\setvalue{\??filleralternative\s!unknown}%
93  {}
94
95\setvalue{\??filleralternative\v!symbol}%
96  {\expandnamespaceparameter\??fillerleadermethod\fillerparameter\c!method\v!local
97     \ifdim\fillerparameter\c!offset>\zeropoint
98        \simplealignedspreadbox
99          {2\dimexpr\fillerparameter\c!offset\relax}%
100          {\fillerparameter\c!align}%
101          {\fillerparameter\c!symbol}%
102     \else
103        \simplealignedbox
104          {\fillerparameter\c!width}%
105          {\fillerparameter\c!align}%
106          {\fillerparameter\c!symbol}%
107     \fi
108   \hfill}
109
110\setvalue{\??filleralternative\v!stretch}%
111  {\hfill}
112
113\setvalue{\??filleralternative\v!space}%
114  {\hskip\fillerparameter\c!distance\relax}
115
116\setvalue{\??filleralternative\v!rule}%
117  {\expandnamespaceparameter\??fillerleadermethod\fillerparameter\c!method\v!local
118     \hrule
119       \s!height\fillerparameter\c!height
120       \s!depth \fillerparameter\c!depth
121   \hfill}
122
123\letvalue{\??fillerleadermethod\s!local }\normalleaders  % overflow ends up inbetween (current box)
124\letvalue{\??fillerleadermethod\v!global}\normalgleaders % overflow ends up inbetween (outermost box)
125\letvalue{\??fillerleadermethod\v!middle}\normalcleaders % overflow ends up before, after (current box)
126\letvalue{\??fillerleadermethod\v!broad }\normalxleaders % overflow ends up before, inbetween, after (current box)
127
128\setupfillers
129  [\c!width=\emwidth,
130   \c!symbol=.,
131   \c!distance=\emwidth,
132   \c!offset=\zeropoint,
133   \c!align=\v!middle,
134   \c!height=.1\exheight,
135   \c!depth=\zeropoint,
136   \c!leftmargin=\zeropoint,
137   \c!rightmargin=\zeropoint,
138   \c!rightmargindistance=\zeropoint,
139   \c!alternative=\v!symbol,
140   \c!method=\s!local]
141
142\definefiller
143  [\v!sym]
144  [\c!method=\v!global,
145   \c!width=.5\emwidth,
146   \c!leftmargin=.5\emwidth,
147   \c!rightmargin=.5\emwidth]
148
149\definefiller
150  [\v!symbol]
151  [\c!method=\v!global,
152   \c!offset=.125\emwidth,
153   \c!leftmargin=.5\emwidth,
154   \c!rightmargin=.5\emwidth]
155
156\definefiller
157  [\v!rule]
158  [\c!alternative=\v!rule,
159   \c!leftmargin=.5\emwidth,
160   \c!rightmargin=.5\emwidth]
161
162\definefiller
163  [\v!width]
164  [\c!alternative=\v!stretch]
165
166\definefiller
167  [\v!space]
168  [\c!alternative=\v!space,
169   \c!distance=3\emwidth]
170
171% bonus:
172
173\definefiller
174  [dotfill]
175  [\c!symbol=\textperiod,
176   \c!style=\v!normal,
177   \c!method=\v!middle,
178   \c!width=.5\emwidth,
179   \c!leftmargin=.2\emwidth,
180   \c!rightmargin=.2\emwidth]
181
182\let\mathdotfill\dotfill
183
184\unexpanded\def\textdotfill{\filler[dotfill]}
185
186\unexpanded\def\dotfill{\mathortext\mathdotfill\textdotfill}
187
188% maybe box -> symbol
189
190\protect \endinput
191
192% \definefiller[test-a][alternative=stretch]
193% \definefiller[test-b][alternative=symbol,symbol=!]
194% \definefiller[test-c][alternative=rule,height=.1ex,leftmargin=.5em,rightmargin=.25em]
195
196% \starttext
197%     text\filler[test-a]text \par
198%     text\filler[test-b]text \par
199%     text\filler[test-c]text \par
200%     text\checkedfiller{<nothing>}text \par
201% \stoptext
202