当我经过时，
并尝试编译以下代码以获取答案中给定的输出，但不幸的是遇到一些错误。
有人能帮帮我吗？我犯了什么错误。
代碼：
\documentclass[tikz]{standalone}
\usepackage{forest,mathtools,siunitx}
\makeatletter
\def\ifNum#1{\ifnum#1\relax
\expandafter\pgfutil@firstoftwo\else
\expandafter\pgfutil@secondoftwo\fi}
\forestset{
num content/.style={
delay={
content/.expanded={\noexpand\num{\forestoption{content}}}}},
pt@prime/.style={draw, circle},
pt@start/.style={},
pt@normal/.style={},
start primeTree/.style={%
/utils/exec=%
% \pt@start holds the current minimum factor, we'll start with 2
\def\pt@start{2}%
% \pt@result will hold the to-be-typeset factorization, we'll start with
% \pgfutil@gobble since we don't want a initial \times
\let\pt@result\pgfutil@gobble
% \pt@start@cnt holds the number of ^factors for the current factor
\def\pt@start@cnt{0}%
% \pt@lStart will later hold "l"ast factor used
\let\pt@lStart\pgfutil@empty,
alias=pt-start,
pt@start/.try,
delay={content/.expanded={$\noexpand\num{\forestove{content}}
\noexpand\mathrlap{{}= \noexpand\pt@result}$}},
primeTree},
primeTree/.code=%
% take the content of the node and save it in the count
\c@pgf@counta\forestove{content}\relax
% if it's 2 we're already finished with the factorization
\ifNum{\c@pgf@counta=2}{%
% add the factor
\pt@addfactor{2}%
% finalize the factorization of the result
\pt@addfactor{}%
% and set the style to the prime style
\forestset{pt@prime/.try}%
}{%
% this simply calculates content/2 and saves it in \pt@end
% this is later used for an early break of the recursion since no factor
% can be greater then content/2 (for integers of course)
\edef\pt@content{\the\c@pgf@counta}%
\divide\c@pgf@counta2\relax
\advance\c@pgf@counta1\relax % to be on the safe side
\edef\pt@end{\the\c@pgf@counta}%
\pt@do}}
%%% our main "function"
\def\pt@do{%
% let's test if the current factor is already greather then the max factor
\ifNum{\pt@end<\pt@start}{%
% great, we're finished, the same as above
\expandafter\pt@addfactor\expandafter{\pt@content}%
\pt@addfactor{}%
\def\pt@next{\forestset{pt@prime/.try}}%
}{%
% this calculates int(content/factor)*factor
% if factor is a factor of content (without remainder), the result will
% equal content. The int(content/factor) is saved in \pgf@temp.
\c@pgf@counta\pt@content\relax
\divide\c@pgf@counta\pt@start\relax
\edef\pgf@temp{\the\c@pgf@counta}%
\multiply\c@pgf@counta\pt@start\relax
\ifNum{\the\c@pgf@counta=\pt@content}{%
% yeah, we found a factor, add it to the result and ...
\expandafter\pt@addfactor\expandafter{\pt@start}%
% ... add the factor as the first child with style pt@prime
% and the result of int(content/factor) as another child.
\edef\pt@next{\noexpand\forestset{%
append={[\pt@start, pt@prime/.try]},
append={[\pgf@temp, pt@normal/.try]},
% forest is complex, this makes sure that for the second child, the
% primeTree style is not executed too early (there must be a better way).
delay={
for descendants={
delay={if n'=1{primeTree, num content}{}}}}}}%
}{%
% Alright this is not a factor, let's get the next factor
\ifNum{\pt@start=2}{%
% if the previous factor was 2, the next one will be 3
\def\pt@start{3}%
}{%
% hmm, the previos factor was not 2,
% let's add 2, maybe we'll hit the next prime number
% and maybe a factor
\c@pgf@counta\pt@start
\advance\c@pgf@counta2\relax
\edef\pt@start{\the\c@pgf@counta}%
}%
% let's do that again
\let\pt@next\pt@do
}%
}%
\pt@next
}
%%% this builds the \pt@result macro with the factors
\def\pt@addfactor#1{%
\def\pgf@tempa{#1}%
% is it the same factor as the previous one
\ifx\pgf@tempa\pt@lStart
% add 1 to the counter
\c@pgf@counta\pt@start@cnt\relax
\advance\c@pgf@counta1\relax
\edef\pt@start@cnt{\the\c@pgf@counta}%
\else
% a new factor! Add the previous one to the product of factors
\ifx\pt@lStart\pgfutil@empty\else
% as long as there actually is one, the \ifnum makes sure we do not add ^1
\edef\pgf@tempa{\noexpand\num{\pt@lStart}\ifnum\pt@start@cnt>1
^{\noexpand\num{\pt@start@cnt}}\fi}%
\expandafter\pt@addfactor@\expandafter{\pgf@tempa}%
\fi
% setup the macros for the next round
\def\pt@lStart{#1}% <- current (new) factor
\def\pt@start@cnt{1}% <- first time
\fi
}
%%% This simply appends "\times #1" to \pt@result, with etoolbox this would be
%%% \appto\pt@result{\times#1}
\def\pt@addfactor@#1{%
\expandafter\def\expandafter\pt@result\expandafter{\pt@result \times #1}}
%%% Our main macro:
%%% #1 = possible optional argument for forest (can be tikz too)
%%% #2 = the number to factorize
\newcommand*{\PrimeTree}[2][]{%
\begin{forest}%
% as the result is set via \mathrlap it doesn't update the bounding box
% let's fix this:
tikz={execute at end scope={\pgfmathparse{width("${}=\pt@result$")}%
\path ([xshift=\pgfmathresult pt]pt-start.east);}},
% other optional arguments
#1
% And go!
[#2, start primeTree]
\end{forest}}
\makeatother
\begin{document}
\PrimeTree{36}
\PrimeTree{90}
\PrimeTree{112}
\PrimeTree{612}
\PrimeTree{7875}
\PrimeTree{22230}
\PrimeTree{1073741824}
\PrimeTree{2147483644}
\end{document}
错误：
line 143: Extra }, or forgotten $. \PrimeTree{36}
line 143: Extra }, or forgotten $. \PrimeTree{36}
line 143: Extra }, or forgotten $. \PrimeTree{36}
line 143: Missing $ inserted. \PrimeTree{36}
line 143: Missing } inserted. \PrimeTree{36}
line 143: Missing } inserted. \PrimeTree{36}
line 143: Missing } inserted. \PrimeTree{36}
line 145: Extra }, or forgotten $. \PrimeTree{112}
line 145: Extra }, or forgotten $. \PrimeTree{112}
line 145: Extra }, or forgotten $. \PrimeTree{112}
line 145: Missing $ inserted. \PrimeTree{112}
line 145: Missing } inserted. \PrimeTree{112}
line 145: Missing } inserted. \PrimeTree{112}
line 145: Missing } inserted. \PrimeTree{112}
line 146: Extra }, or forgotten $. \PrimeTree{612}
line 146: Extra }, or forgotten $. \PrimeTree{612}
line 146: Extra }, or forgotten $. \PrimeTree{612}
line 146: Missing $ inserted. \PrimeTree{612}
line 146: Missing } inserted. \PrimeTree{612}
line 146: Missing } inserted. \PrimeTree{612}
line 146: Missing } inserted. \PrimeTree{612}
line 147: Extra }, or forgotten $. \PrimeTree{7875}
line 147: Extra }, or forgotten $. \PrimeTree{7875}
line 147: Extra }, or forgotten $. \PrimeTree{7875}
line 147: Missing $ inserted. \PrimeTree{7875}
line 147: Missing } inserted. \PrimeTree{7875}
line 147: Missing } inserted. \PrimeTree{7875}
line 147: Missing } inserted. \PrimeTree{7875}
line 149: Extra }, or forgotten $. \PrimeTree{1073741824}
line 149: Extra }, or forgotten $. \PrimeTree{1073741824}
line 149: Extra }, or forgotten $. \PrimeTree{1073741824}
line 149: Missing $ inserted. \PrimeTree{1073741824}
line 149: Missing } inserted. \PrimeTree{1073741824}
line 149: Missing } inserted. \PrimeTree{1073741824}
line 149: Missing } inserted. \PrimeTree{1073741824}
line 150: Extra }, or forgotten $. \PrimeTree{2147483644}
line 150: Extra }, or forgotten $. \PrimeTree{2147483644}
line 150: Extra }, or forgotten $. \PrimeTree{2147483644}
line 150: Missing $ inserted. \PrimeTree{2147483644}
line 150: Missing } inserted. \PrimeTree{2147483644}
line 150: Missing } inserted. \PrimeTree{2147483644}
line 150: Missing } inserted. \PrimeTree{2147483644}