指向方程特定变量的倾斜箭头

Question

如何制作指向特定位置的倾斜箭头，如图所示

Answer 1

实现这一目标的无数方法之一：

\documentclass{beamer}
\usepackage{tikz}
\usetikzlibrary{positioning, fit}
\usetikzlibrary{arrows.meta}
\tikzset{
    ttnode/.style={
        font=\ttfamily, 
        inner xsep=0pt,
        }
    }
\begin{document}

\begin{frame}[fragile]

    \begin{tikzpicture}
        \node (first) {The general function call is:};
        \node[ttnode, below=-2pt of first](second){var=zeroes(};
        \node[ttnode, green, right=0pt of second.base east, anchor=base west](toM){M};
        \node[ttnode, right=0pt of toM.base east, anchor=base west](comma){,};
        \node[ttnode, blue, right=0pt of comma.base east, anchor=base west](toN){N};    
        \node[ttnode, right=0pt of toN.base east, anchor=base west]{);};
        \node[green, below left= of toM](fromM){Number of rows};
        \node[blue, below right= of toN](fromN){Number of colunms};
        \node[blue, fit=(first)(fromM)(fromN), draw]{};
        \draw[-Triangle, green] (fromM) to[out=90, in=-90] (toM.south);
        \draw[-Triangle, blue] (fromN) to[out=90, in=-90] (toN.south);
    \end{tikzpicture}

\end{frame}

\end{document}