fermi/pretty/pretty.go

package pretty

import (
	"errors"
	"fmt"
	"math"
	"strconv"
)

func PrettyPrintInt(n int) {
	switch {
	case math.Abs(float64(n)) >= 1_000_000_000_000:
		fmt.Printf("%dT", n/1_000_000_000_000)
	case math.Abs(float64(n)) >= 1_000_000_000:
		fmt.Printf("%dB", n/1_000_000_000)
	case math.Abs(float64(n)) >= 1_000_000:
		fmt.Printf("%dM", n/1_000_000)
	case math.Abs(float64(n)) >= 1_000:
		fmt.Printf("%dK", n/1_000)
	default:
		fmt.Printf("%df", n)
	}
}

func PrettyPrintFloat(f float64) {
	switch {
	case math.Abs(f) >= 1_000_000_000_000:
		fmt.Printf("%.1fT", f/1_000_000_000_000)
	case math.Abs(f) >= 1_000_000_000:
		fmt.Printf("%.1fB", f/1_000_000_000)
	case math.Abs(f) >= 1_000_000:
		fmt.Printf("%.1fM", f/1_000_000)
	case math.Abs(f) >= 1_000:
		fmt.Printf("%.1fK", f/1_000)

	case math.Abs(f) <= 0.0001:
		fmt.Printf("%.5f", f)
	case math.Abs(f) <= 0.001:
		fmt.Printf("%.4f", f)
	case math.Abs(f) <= 0.01:
		fmt.Printf("%.3f", f)
	case math.Abs(f) <= 0.1:
		fmt.Printf("%.2f", f)
	default:
		fmt.Printf("%.1f", f)
	}

}
func PrettyPrint2Floats(low float64, high float64) {
	PrettyPrintFloat(low)
	fmt.Printf(" ")
	PrettyPrintFloat(high)
}

func multiplyOrPassThroughError(a float64, b float64, err error) (float64, error) {
	if err != nil {
		return b, err
	} else {
		return a * b, nil
	}
}

func ParseFloat(word string) (float64, error) {
	// l = len(word) // assuming no UTF stuff
	switch len(word) {
	case 0:
		return 0, errors.New("String to be parsed into float must not be the empty string")
	case 1:
		return strconv.ParseFloat(word, 64)
	}

	n := len(word) - 1
	f, err := strconv.ParseFloat(word[:n], 64)
	switch word[n] {
	case 'K':
		return multiplyOrPassThroughError(1_000, f, err)
	case 'M':
		return multiplyOrPassThroughError(1_000_000, f, err)
	case 'B':
		return multiplyOrPassThroughError(1_000_000_000, f, err)
	case 'T':
		return multiplyOrPassThroughError(1_000_000_000_000, f, err)
	default:
		return strconv.ParseFloat(word, 64)
	}

}