Function lhsNames

src/compute-engine/rubi/compile.ts:169–182

Pattern-variable names appearing in a rule LHS (excluding the variable).

(
  lhs: Json,
  variable: string,
  out = new Set<string>()
)

      expr.symbol.startsWith(OPT)
    );
  if (!expr.ops) return false;
  return expr.ops.some(hasPlaceholder);
}

/** Pattern-variable names appearing in a rule LHS (excluding the variable). */
function lhsNames(
  lhs: Json,
  variable: string,
  out = new Set<string>()
): Set<string> {
  if (
    (isCall(lhs, 'Blank') || isCall(lhs, 'BlankOptional')) &&
    typeof lhs[1] === 'string'
  ) {
    if (lhs[1] !== variable) out.add(lhs[1]);
  } else if (Array.isArray(lhs))
    for (const a of lhs.slice(1)) lhsNames(a, variable, out);