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% Tree -- a macro to make aligned (horizontal) trees in TeX
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% Nesting is to any level. \leaf is defined as a subtree of one item:
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% \def\leaf#1{\subtree#1\endsubtree}.
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% will print item_part2 directly below item_part1 as a single item
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% as if they were in a \box.
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% The macro is a 3-pass macro. On the first pass it sets up a data
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% structure from the \subtree ... \endsubtree definitions. On the second pass
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% it recursively calculates the width of each level of the tree. On the third
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% pass it sets up the boxes, glue and rules.
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% By David Eppstein, TUGboat, vol. 6 (1985), no. 1, pp. 31--35.
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% Transcribed by Margaret Kromer (peg), Feb., 1986.
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% At the end of pass 1, the tree is coded as a nested collection of \hboxes
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\newbox\treebox\newcount\treeboxcnt
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\def\tree{\message{Begin tree}\treeboxcnt=1\global\setbox\treebox=\boxtree}
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\def\subtree{\ettext \advance\treeboxcnt by 1 \boxtree}
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\def\leaf#1{\subtree#1\endsubtree}
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\def\endsubtree{\ettext \egroup \advance\treeboxcnt-1{}%
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\ifnum\treeboxcnt=-1 \treeerrora\fi}
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\def\endtree{\endsubtree \ifnum\treeboxcnt>0 \treeerrorb\fi%
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\settreesizes \typesettree \message{-- end tree}}
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% Error messages for unbalanced tree
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\def\treeerrora{\errhelp=\treeerrorahelp%
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\errmessage{Unbalanced tree -- too many endsubtrees}}
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\newhelp\treeerrorahelp{There are more subtrees closed than opened}
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\def\treeerrorb{\errhelp=\treeerrorbhelp%
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\errmessage{Unbalanced tree -- not enough endsubtrees}}
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\newhelp\treeerrorbhelp{Not all the subtrees of the tree are closed.
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If you continue, you'll get some mysterious secondary errors.}
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% Set up \vbox containing root of tree
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\newif\iftreetext\treetextfalse % Whether still aligning text
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\def\boxtree{\hbox\bgroup % Start outer box of tree or subtree
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\baselineskip 2.5ex % Narrow line spacing slightly
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\tabskip 0pt % No spurious glue in alignment
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\vbox\bgroup % Start inner text \vbox
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\treetexttrue % Remember for \ettext
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\let\par\crcr \obeylines % New line breaks without explicit \cr
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\halign\bgroup##\hfil\cr} % Start alignment with simple template
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\def\ettext{\iftreetext % Are we still in inner text \vbox?
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\crcr\egroup \egroup \fi} % Yes, end alignment and box
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% Recursively calculate widths of tree with \setsizes; keep results in
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% \treesizes; \treewidth contains total width calculated so far. \treeworkbox
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% is workspace containing subtree being sized.
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\def\cons#1#2{\edef#2{\xmark #1#2}} % Add something to start of list
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\def\car#1{\expandafter\docar#1\docar} % Take first element of list
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\def\docar\xmark#1\xmark#2\docar{#1} % ..by ignoring rest in expansion
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\def\cdr#1{\expandafter\docdr#1\docdr#1}% Similarly, drop first element
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\def\docdr\xmark#1\xmark#2\docdr#3{\def#3{\xmark #2}}
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\def\xmark{\noexpand\xmark} % List separator expands to self
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\def\nil{\xmark} % Empty list is just separator
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\def\settreesizes{\setbox\treeworkbox=\copy\treebox%
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\global\let\treesizes\nil \setsizes}
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\newdimen\treewidth % Width of this part of the tree
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\def\setsizes{\setbox\treeworkbox=\hbox\bgroup% Get a horiz list as a workspace
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\unhbox\treeworkbox\unskip % Take tree, unpack it into horiz list
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\inittreewidth % Get old width at this level
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\sizesubtrees % Recurse through all subtrees
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\sizelevel % Now set width from remaining \vbox
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\egroup} % All done, finish our \hbox
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\def\inittreewidth{\ifx\treesizes\nil % If this is the first at this level
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\treewidth=0pt % ..then we have no previous max width
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\else \treewidth=\car\treesizes % Otherwise take old max level width
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\global\cdr\treesizes % ..and advance level width storage
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\fi} % ..in preparation for next level.
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\def\sizesubtrees{\loop % For each box in horiz list (subtree)
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\setbox\treeworkbox=\lastbox \unskip % ..pull it off list and flush glue
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\ifhbox\treeworkbox \setsizes % If hbox, it's a subtree - recurse
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\repeat} % ..and loop; end loop on tree text
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\ifdim\treewidth<\wd\treeworkbox % If greater than previous maximum
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\treewidth=\wd\treeworkbox \fi % Then set max to new high
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\global\cons{\the\treewidth}\treesizes}% In either case, put back on list
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% Recursively typeset tree with \maketree by adding an \hbox containing
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% a subtree (in \treebox) to the horizontal list.
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\newdimen\treeheight % Height of this part of the tree
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\newif\ifleaf % Tree has no subtrees (is a leaf)
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\newif\ifbotsub % Bottom subtree of parent
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\newif\iftopsub % Top subtree of parent
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\def\typesettree{\medskip\maketree\medskip} % Make whole tree
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\def\maketree{\hbox{\treewidth=\car\treesizes % Get width at this level
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\cdr\treesizes % Set up width list for recursion
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\makesubtreebox\unskip % Set \treebox to text, make subtrees
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\ifleaf \makeleaf % No subtrees, add glue
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\else \makeparent \fi}} % Have subtrees, stick them at right
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{\catcode`@=11 % Be able to use \voidb@x
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\gdef\makesubtreebox{\unhbox\treebox % Open up tree or subtree
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\unskip\global\setbox\treebox\lastbox % Pick up very last box
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\ifvbox\treebox % If we're already at the \vbox
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\global\leaftrue \let\next\relax % ..then this is a leaf
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\else \botsubtrue % Otherwise, we have subtrees
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\setbox\treeworkbox\box\voidb@x % Init stack of processed subs
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\botsubtrue \let\next\makesubtree % ..and call \maketree on them
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\fi \next}} % Finish up for whichever it was
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\def\makesubtree{\setbox1\maketree % Call \maketree on this subtree
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\unskip\global\setbox\treebox\lastbox % Pick up box before it
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\treeheight=\ht1 % Get height of subtree we made
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\advance\treeheight 2ex % Add some room around the edges
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\ifhbox\treebox \topsubfalse % If picked up box is a \vbox,
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\else \topsubtrue \fi % ..this is the top, otherwise not
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\addsubtreebox % Stack subtree with the rest
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\iftopsub \global\leaffalse % If top, remember not a leaf
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\let\next\relax \else % ..(after recursion), set return
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\botsubfalse \let\next\makesubtree % Otherwise, we have more subtrees
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\fi \next} % Do tail recursion or return
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\def\addsubtreebox{\setbox\treeworkbox=\vbox{\subtreebox\unvbox\treeworkbox}}
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\def\subtreebox{\hbox\bgroup % Start \hbox of tree and lines
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\vbox to \treeheight\bgroup % Start \vbox for vertical rules
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\ifbotsub \iftopsub \vfil % If both bottom and top subtree
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\hrule width 0.4pt % ..vertical rule is just a dot
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\else \treehalfrule \fi \vfil % Bottom gets half-height rule
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\else \iftopsub \vfil \treehalfrule % Top gets half-height the other way
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\else \hrule width 0.4pt height \treeheight \fi\fi % Middle, full height
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\egroup % Finish vertical rule \vbox
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\treectrbox{\hrule width 1em}\hskip 0.2em\treectrbox{\box1}\egroup}
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\def\treectrbox#1{\vbox to \treeheight{\vfil #1\vfil}}
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\def\treehalfrule{\dimen\treeworkbox=\treeheight % Get total height
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\divide\dimen\treeworkbox 2%
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\advance\dimen\treeworkbox 0.2pt % Divide by two, add half horiz height
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\hrule width 0.4pt height \dimen\treeworkbox}% Make a vertical rule that high
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\def\makeleaf{\box\treebox} % Add leaf box to horiz list
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\def\makeparent{\ifdim\ht\treebox>%
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\ht\treeworkbox % If text is higher than subtrees
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\treeheight=\ht\treebox % ..use that height
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\else \treeheight=\ht\treeworkbox \fi % Otherwise use height of subtrees
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\advance\treewidth-\wd\treebox % Take remainder of level width
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\advance\treewidth 1em % ..after accounting for text and glue
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\treectrbox{\box\treebox}\hskip 0.2em % Add text, space before connection
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\treectrbox{\hrule width \treewidth}%
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\treectrbox{\box\treeworkbox}} % Add \hrule, subs
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% No idea what \spouse is supposed to do... wasn't included
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removed
reports/desc-tex2/tree.tex
