Function prepareExpression

fbclock/daemon/math.go:203–220

(exprStr string)

}

func prepareExpression(exprStr string) (expr *govaluate.EvaluableExpression, err error) {
	defer func() {
		if r := recover(); r != nil {
			expr = nil
			err = fmt.Errorf("invalid expression %q: %v", exprStr, r)
		}
	}()
	expr, err = govaluate.NewEvaluableExpressionWithFunctions(exprStr, functions)
	if err != nil {
		return nil, err
	}
	for _, v := range expr.Vars() {
		if !isSupportedVar(v) {
			return nil, fmt.Errorf("unsupported variable %q", v)
		}
	}
	return expr, nil
}

func prepareMathParameters(lastN []*DataPoint) map[string][]float64 {
	size := len(lastN)