How about using tagged template literals for evaluating expressions?

[mrft]

Inspired by things like lit-html and uhtml, where you can simply write:

html`<p>Hello ${name}</p>`

and realizing that mathjs already supports compiled expressions with const expr = math.compile(...) and const result = expr.evaluate(scope)
I thought, why don't we simply allow to write things like:

const results = manyScopes
  .map((scope) => mathEval`${scope.a} + 3m * ${scope.b}^2`;

which stays as close as possible to a mathematical notation while inlining the variable names directly in the formula.

More info about tagged templates

I wrote a quick example to show how this might work (with memoization built-in in order to avoid recompiling the same template multiple times).

function mathEval(strings: TemplateStringsArray, ...values: Array<math.Primitive>): math.Primitive {
  // Combine the strings and values into a single expression
  const expression = strings.reduce(
    (acc, str, i) => acc + str + (values[i] !== undefined ? ` var${i} ` : ""),
    ""
  );

  // Check if we have a compiled version cached
  let compiled = expressionCache.get(expression);
  if (!compiled) {
    // Compile and cache the expression
    compiled = math.compile(expression);
    expressionCache.set(expression, compiled);
  } else {
    // Using cached compiled expression
  }

  // Create a scope object with the variables
  const scope = values.reduce((acc, val, i) => {
    acc[`var${i}`] = val;
    return acc;
  }, {});

  return compiled.evaluate(scope);
}

// Example usage
let myVar = 5;
let a = 2;
let b = math.unit(10, "m");
console.log(mathEval`${math.unit(a, "m")} + 3m * ${myVar}^2`.toString());

console.log(mathEval`${b} + 3m * ${myVar}^2`.toString());

console.log(mathEval`${20}m + 3m * ${myVar}^2`.toString());

What are your thoughts?

[josdejong]

Template literals be really useful indeed. We've discussed it in #3393 (includes a working example too).

[mrft]

Oops, I missed that one.

[josdejong]

No problem, thanks for your inputs and thinking along!