Function wildcardize

scripts/fungrim/compile-rules.ts:165–172

(
  x: MathJSON,
  variables: ReadonlyArray<string>
)

// ---------------------------------------------------------------------------

/** Rename each entry variable `z` to the wildcard `_z` (pure tree rewrite). */
export function wildcardize(
  x: MathJSON,
  variables: ReadonlyArray<string>
): MathJSON {
  if (typeof x === 'string') return variables.includes(x) ? '_' + x : x;
  if (Array.isArray(x)) return x.map((y) => wildcardize(y, variables));
  return x;
}

/** Substitute wildcard symbols by MathJSON fragments. */