added support for *url.URL fields

replaced golang.org with pkg.go.dev links in README

README.md

@@ -26,9 +26,11 @@ err := config.FromEnv().To(&c)
 
 It's just simple, pure stdlib. 
 
-* A field's type determines what [strconv](https://golang.org/pkg/strconv/) function is called.
-* All string conversion rules are as defined in the [strconv](https://golang.org/pkg/strconv/) package
-* time.Duration follows the same parsing rules as [time.ParseDuration](https://golang.org/pkg/time#ParseDuration)
+* A field's type determines what [strconv](https://pkg.go.dev/strconv) function is called.
+* All string conversion rules are as defined in the [strconv](https://pkg.go.dev/strconv) package
+* `time.Duration` follows the same parsing rules as [time.ParseDuration](https://pkg.go.dev/time#ParseDuration)
+* `*net.URL` follows the same parsing rules as [url.Parse](https://pkg.go.dev/net/url#URL.Parse)
+  * NOTE: `*net.URL` fields on the struct **must** be a pointer
 * If chaining multiple data sources, data sets are merged. 
   Later values override previous values.
   ```go
@@ -70,3 +72,4 @@ Feel free to use it on its own, or alongside other libraries.
 * No maps. The only feature of maps not handled by structs for this usecase is dynamic keys.
 
 * No pointer members. If you really need one, just take the address of parts of your struct.
+  * One exception is `*url.URL`, which is explicitly a pointer for ease of use, matching the `url` package conventions

api.go

@@ -25,6 +25,7 @@ type Builder struct {
 //     * all int, uint, float variants
 //     * bool, struct, string
 //     * time.Duration
+//     * \*url.URL
 //     * slice of any of the above, except for []struct{}
 // It returns an error if:
 //     * struct contains unsupported fields (pointers, maps, slice of structs, channels, arrays, funcs, interfaces, complex)

api_test.go

@@ -1,6 +1,7 @@
 package config_test
 
 import (
+	"net/url"
 	"os"
 	"reflect"
 	"strings"
@@ -29,6 +30,12 @@ func Test_Api(t *testing.T) {
 		K string
 		L time.Duration
 		M int8
+		U *url.URL
+	}
+	wantUrl := "https://google.com/search?q=golang"
+	wantUrlParsed, err := url.Parse(wantUrl)
+	if err != nil {
+		t.Fatalf("could not parse wanted URL: %v", err)
 	}
 
 	file, err := os.CreateTemp("", "testenv")
@@ -54,6 +61,7 @@ func Test_Api(t *testing.T) {
 		"I=",      // should NOT log I as there is no way to tell if it is missing or deliberately empty
 		"L=8h",
 		"M=128", // should fail as it is out of bounds for an int8
+		"U=" + wantUrl,
 	}, "\n")
 	_, err = file.Write([]byte(testData))
 	if err != nil {
@@ -87,6 +95,7 @@ func Test_Api(t *testing.T) {
 		K: "hardcoded",
 		L: eightHours,
 		M: 0,
+		U: wantUrlParsed,
 	}
 	wantError := "config: the following fields had errors: [file[nonexistfile] g[1] h m]"
 

doc.go

@@ -4,11 +4,14 @@
 //     var c MyConfig
 //     config.FromEnv().To(&c)
 //
-// A field's type determines what https://golang.org/pkg/strconv/ function is called.
+// A field's type determines what https://pkg.go.dev/strconv function is called.
 //
-// All string conversion rules are as defined in the https://golang.org/pkg/strconv/ package.
+// All string conversion rules are as defined in the https://pkg.go.dev/strconv package.
 //
-// time.Duration follows the same parsing rules as https://golang.org/pkg/time#ParseDuration
+// time.Duration follows the same parsing rules as https://pkg.go.dev/time#ParseDuration
+//
+// *net.URL follows the same parsing rules as https://pkg.go.dev/net/url#URL.Parse
+// NOTE: `*net.URL` fields on the struct **must** be a pointer
 //
 // If chaining multiple data sources, data sets are merged.
 //

util.go

@@ -2,6 +2,7 @@ package config
 
 import (
 	"fmt"
+	"net/url"
 	"reflect"
 	"strconv"
 	"strings"
@@ -122,8 +123,14 @@ func convertAndSetValue(settable reflect.Value, s string) bool {
 		u   uint64
 		b   bool
 		f   float64
+		url *url.URL
 	)
 	switch settableValue.Kind() {
+	case reflect.Ptr: // only one pointer type is handled at the moment, *url.URL
+		url, err = url.Parse(s)
+		if err == nil {
+			settableValue.Set(reflect.ValueOf(url))
+		}
 	case reflect.String:
 		settableValue.SetString(s)
 	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64: