Implement a Formula Parser / Evaluator

Problem Parse and evaluate a simple spreadsheet-style formula supporting +, -, *, /, parentheses, and cell references (Coda blends docs with a formula/spreadsheet layer).

Input / Output

• Input: a formula string (e.g. "=2*(A1+3)") and a map of cell values.
• Output: the numeric result.

Constraints

• Valid expression; respect operator precedence and parentheses.
• Resolve cell references from the provided values.

Example

• "=2*(A1+3)" with A1=4 → 14.