move to lib

cmd/shoelace.go

@@ -24,15 +24,11 @@ import (
 	"strings"
 
 	"github.com/spf13/cobra"
+	"scm.dairydemon.net/filifa/mathtools/internal/lib"
 )
 
 var shoelaceFile string
 
-type point struct {
-	x float64
-	y float64
-}
-
 func splitLines(file *os.File) []string {
 	slice := make([]string, 0)
 	scanner := bufio.NewScanner(file)
@@ -43,8 +39,8 @@ func splitLines(file *os.File) []string {
 	return slice
 }
 
-func readFromFile(filepath string) ([]point, error) {
-	points := make([]point, 0)
+func readFromFile(filepath string) ([]lib.Point, error) {
+	points := make([]lib.Point, 0)
 	file, err := os.Open(filepath)
 	if err != nil {
 		return points, err
@@ -65,25 +61,14 @@ func readFromFile(filepath string) ([]point, error) {
 			return points, err
 		}
 
-		points = append(points, point{x, y})
+		points = append(points, lib.Point{x, y})
 	}
 
 	return points, nil
 }
 
-func area(points []point) float64 {
-	total := float64(0)
-	n := len(points)
-	for i, p := range points {
-		q := points[(i+1)%n]
-		total += (p.y + q.y) * (p.x - q.x)
-	}
-
-	return total / 2
-}
-
 func shoelace(cmd *cobra.Command, args []string) {
-	var coordinates []point
+	var coordinates []lib.Point
 	var err error
 	if shoelaceFile != "" {
 		coordinates, err = readFromFile(shoelaceFile)
@@ -94,7 +79,7 @@ func shoelace(cmd *cobra.Command, args []string) {
 		cobra.CheckErr("filename required")
 	}
 
-	fmt.Println(area(coordinates))
+	fmt.Println(lib.Area(coordinates))
 }
 
 // shoelaceCmd represents the shoelace command