Function alignedHandler

static/katex/katex.mjs:9552–9632

(context, args)

const alignedHandler = function alignedHandler(context, args) {
  const cols = [];
  const res = parseArray(context.parser, {
    cols,
    addJot: true
  }, "display"); // Determining number of columns.
  // 1. If the first argument is given, we use it as a number of columns,
  //    and makes sure that each row doesn't exceed that number.
  // 2. Otherwise, just count number of columns = maximum number
  //    of cells in each row ("aligned" mode -- isAligned will be true).
  //
  // At the same time, prepend empty group {} at beginning of every second
  // cell in each row (starting with second cell) so that operators become
  // binary.  This behavior is implemented in amsmath's \start@aligned.

  let numMaths;
  let numCols = 0;
  const emptyGroup = {
    type: "ordgroup",
    mode: context.mode,
    body: []
  };
  const ordgroup = checkNodeType(args[0], "ordgroup");

  if (ordgroup) {
    let arg0 = "";

    for (let i = 0; i < ordgroup.body.length; i++) {
      const textord = assertNodeType(ordgroup.body[i], "textord");
      arg0 += textord.text;
    }

    numMaths = Number(arg0);
    numCols = numMaths * 2;
  }

  const isAligned = !numCols;
  res.body.forEach(function (row) {
    for (let i = 1; i < row.length; i += 2) {
      // Modify ordgroup node within styling node
      const styling = assertNodeType(row[i], "styling");
      const ordgroup = assertNodeType(styling.body[0], "ordgroup");
      ordgroup.body.unshift(emptyGroup);
    }

    if (!isAligned) {
      // Case 1
      const curMaths = row.length / 2;

      if (numMaths < curMaths) {
        throw new ParseError("Too many math in a row: " + `expected ${numMaths}, but got ${curMaths}`, row[0]);
      }
    } else if (numCols < row.length) {
      // Case 2
      numCols = row.length;
    }
  }); // Adjusting alignment.
  // In aligned mode, we add one \qquad between columns;