Function parseExpression

packages/language-python/src/nodes/utils.ts:254–304

(tokens: SplootNode[], currentIndex: number, minPrecedence: number)

}

function parseExpression(tokens: SplootNode[], currentIndex: number, minPrecedence: number): [boolean, number] {
  if (currentIndex >= tokens.length) {
    // Ran out of tokens
    return [true, currentIndex]
  }

  let lookahead = tokens[currentIndex]
  while (
    lookahead &&
    lookahead.type === 'PYTHON_BINARY_OPERATOR' &&
    BinaryOperators[(lookahead as PythonBinaryOperator).getOperator()] &&
    BinaryOperators[(lookahead as PythonBinaryOperator).getOperator()].precedence >= minPrecedence
  ) {
    const operator = (lookahead as PythonBinaryOperator).getOperator()
    const precedence = BinaryOperators[operator].precedence
    currentIndex += 1
    let valid = false
    ;[valid, currentIndex] = parseLeaf(tokens, currentIndex)
    if (!valid) {
      // Leaf RHS was invalid
      return [false, currentIndex]
    }
    if (currentIndex === tokens.length) {
      return [true, currentIndex]
    }

    lookahead = tokens[currentIndex]
    while (
      lookahead &&
      lookahead.type === 'PYTHON_BINARY_OPERATOR' &&
      BinaryOperators[(lookahead as PythonBinaryOperator).getOperator()] &&
      BinaryOperators[(lookahead as PythonBinaryOperator).getOperator()].precedence > precedence
    ) {
      const secondOp = (lookahead as PythonBinaryOperator).getOperator()
      const secondPrecedence = BinaryOperators[secondOp].precedence
      let exprValid = false
      ;[exprValid, currentIndex] = parseExpression(tokens, currentIndex, secondPrecedence)
      if (!exprValid) {
        // Invalid secondary parse
        return [false, currentIndex]
      }
      if (currentIndex < tokens.length) {
        lookahead = tokens[currentIndex]
      } else {
        lookahead = null
      }
    }
  }
  // Have parsed all valid operators
  return [true, currentIndex]
}

export function validateExpressionParse(tokens: SplootNode[]): [boolean, number] {
  const [valid, index] = parseLeaf(tokens, 0)