Graphviz dot of a mathematical expression in a binary tree

expression_sum.dot

// https://stackoverflow.com/questions/23429600/how-do-i-make-a-dot-graph-representing-a-binary-tree-more-symmetric

digraph G
{
    nodesep=0.4; //was 0.8
    ranksep=0.5;

    label="((10 - 25) + (40 * 50))"

    { node[style=invis, label=""]; cx_root; }

    { node[style=invis, label="", width=.1]; ocx_001_multiply_symbol; ocx_001_minus_symbol; }

    { node[label="+"]; "000_plus_symbol"; }

    { node[label="-"]; "001_minus_symobl"; }
    { node[label="*"]; "001_multiply_symbol"; }

    { rank=same; "001_minus_symobl"; "001_multiply_symbol"; cx_root }
    { rank=same; 10; 25; ocx_001_minus_symbol }
    { rank=same; 40; 50; ocx_001_multiply_symbol }

    "000_plus_symbol" -> "001_minus_symobl";
    "000_plus_symbol" -> "001_multiply_symbol";
    "001_minus_symobl" -> 10;
    "001_minus_symobl" -> 25;

    "001_multiply_symbol" -> 40;
    "001_multiply_symbol" -> 50;

    {
        edge[style=invis];

        //Distantiate nodes
        "000_plus_symbol" -> cx_root;
        "001_minus_symobl" -> cx_root -> "001_multiply_symbol";

        //Force ordering between children
        "001_multiply_symbol" -> ocx_001_multiply_symbol;
        40 -> ocx_001_multiply_symbol -> 50;
        "001_minus_symobl" -> ocx_001_minus_symbol;
        10 -> ocx_001_minus_symbol -> 25;
    } 
} 

expression_sum.png