inancgumus/learngo · error

Please provide a valid number: <err>

Error message

Please provide a valid number: <err>

What it means

Parse() wraps strconv.ParseFloat's error when the input string (snum) is not a valid 64-bit floating-point number. The original parse error is deliberately concatenated so the underlying cause is not lost for debugging; the caller (main) gets a user-friendly prompt instead of a raw strconv message.

Source

Thrown at x-tba/foundations/calc/09-packages/calc/calc.go:21

// Parse ...
func Parse(snum string) (n float64, err error) {
	n, err = strconv.ParseFloat(snum, 64)
	if err != nil {
		// Don't loose the actual error for debugging
		err = errors.New("Please provide a valid number: " +
			err.Error())
	}
	return
}

View on GitHub (pinned to 3c475a78e5)

Solutions

1. Print the returned error and prompt the user to re-enter the number.
2. Before calling calc.Parse, trim whitespace and verify the token contains only digits, sign, and decimal point.
3. Accept the error as terminal input validation feedback; there is no recovery beyond asking again.

When it happens

Trigger: Thrown at x-tba/foundations/calc/09-packages/calc/calc.go:21 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of inancgumus/learngo@3c475a78e5 (2026-09-02). Data as JSON: /api/errors/3f211d86880e2d07. Report an issue: GitHub.