如何绘制解析树,例如这里的例子
答案1
这棵树可以很容易地使用TikZ
:
\documentclass{article}
\usepackage{tikz}
\usetikzlibrary{calc,fit,trees}
\begin{document}
\begin{tikzpicture}[
grow'=up,
level 1/.style={sibling distance=14em},
level 2/.style={sibling distance=6em}]
\node (f) {False}
child { node (1l) {$p(a)$}
child {node (2ll) {$\neg p(a)$}}
child {node (2lr) {$p(a)\vee p(b)$}}
}
child {node (1r) {$\neg p(a)$}
child {node (2rl) {$p(X)\vee r(X)$}}
child {node (2rr) {$\neg r(b)$}}
};
\end{tikzpicture}
\end{document}
唯一可能不那么简单的是绘制一些公式组周围的闭合路径;这里的一种可能的方法是使用Jake's answer
到凸包的填充边界:
\documentclass{article}
\usepackage{tikz}
\usetikzlibrary{calc,fit,trees}
\newcommand{\convexpath}[2]{
[
create hullnodes/.code={
\global\edef\namelist{#1}
\foreach [count=\counter] \nodename in \namelist {
\global\edef\numberofnodes{\counter}
\node at (\nodename) [draw=none,name=hullnode\counter] {};
}
\node at (hullnode\numberofnodes) [name=hullnode0,draw=none] {};
\pgfmathtruncatemacro\lastnumber{\numberofnodes+1}
\node at (hullnode1) [name=hullnode\lastnumber,draw=none] {};
},
create hullnodes
]
($(hullnode1)!#2!-90:(hullnode0)$)
\foreach [
evaluate=\currentnode as \previousnode using \currentnode-1,
evaluate=\currentnode as \nextnode using \currentnode+1
] \currentnode in {1,...,\numberofnodes} {
-- ($(hullnode\currentnode)!#2!-90:(hullnode\previousnode)$)
let \p1 = ($(hullnode\currentnode)!#2!-90:(hullnode\previousnode) - (hullnode\currentnode)$),
\n1 = {atan2(\x1,\y1)},
\p2 = ($(hullnode\currentnode)!#2!90:(hullnode\nextnode) - (hullnode\currentnode)$),
\n2 = {atan2(\x2,\y2)},
\n{delta} = {-Mod(\n1-\n2,360)}
in
{arc [start angle=\n1, delta angle=\n{delta}, radius=#2]}
}
-- cycle
}
\begin{document}
\begin{tikzpicture}[
grow'=up,
level 1/.style={sibling distance=14em},
level 2/.style={sibling distance=6em}]
\node (f) {False}
child { node (1l) {$p(a)$}
child {node (2ll) {$\neg p(a)$}}
child {node (2lr) {$p(a)\vee p(b)$}}
}
child {node (1r) {$\neg p(a)$}
child {node (2rl) {$p(X)\vee r(X)$}}
child {node (2rr) {$\neg r(b)$}}
};
\draw[cyan!70!black] \convexpath{f,1l.west,1r.east}{13pt};
\draw[red!70!black] \convexpath{1r,2rl.west,2rr.east}{12pt};
\end{tikzpicture}
\end{document}
您可以访问与以下内容相关的许多资源TikZ
:
- 这
pgf manual
。 - 这
minimal introduction to TikZ
。 - 这
examples gallery
在 TeXample.net - 本网站上有大量示例。