Similar pattern to json unmarshaler but utilizing a generic

Author: Paul FREAKN Baker

regexstruct_118.go

@@ -6,8 +6,6 @@ package regexstruct
 import (
 	"fmt"
 	"regexp"
-
-	"github.com/mitchellh/mapstructure"
 )
 
 type NoMatchError struct {
@@ -20,13 +18,17 @@ func (nme NoMatchError) Error() string {
 	return fmt.Sprintf("the regex (%s) did not match the input string (%s)", pattern, nme.input)
 }
 
-func RegexMatch[T any](r *regexp.Regexp, s string, item *T) error {
+type Unmarshaler interface {
+	Unmarshal(map[string]string) error
+}
+
+func RegexMatch[T Unmarshaler](r *regexp.Regexp, s string, item T) error {
 	matchedMap, isMatch := RegexMatchMap(r, s)
 	if !isMatch {
 		return NoMatchError{
 			regex: r,
 			input: s,
 		}
 	}
-	return mapstructure.Decode(matchedMap, item)
+	return item.Unmarshal(matchedMap)
 }

regexstruct_118_test.go

@@ -10,23 +10,28 @@ import (
 	"github.com/stretchr/testify/assert"
 )
 
+type example struct {
+	first  string
+	second string
+}
+
+func (e *example) Unmarshal(m map[string]string) error {
+	e.first = m["first"]
+	e.second = m["second"]
+	return nil
+}
+
 func TestRegexMatch(t *testing.T) {
 	regex := regexp.MustCompile(`/(?P<first>\w+)/(?P<second>\w+)`)
 	input := "/this_is_first/this_is_second"
-	expected := struct {
-		First  string
-		Second string
-	}{
-		First:  "this_is_first",
-		Second: "this_is_second",
+	expected := example{
+		first:  "this_is_first",
+		second: "this_is_second",
 	}
-	actual := struct {
-		First  string
-		Second string
-	}{}
+	actual := example{}
 	err := RegexMatch(regex, input, &actual)
 	assert.NoError(t, err)
 
-	assert.Equal(t, expected.First, actual.First)
-	assert.Equal(t, expected.Second, actual.Second)
+	assert.Equal(t, expected.first, actual.first)
+	assert.Equal(t, expected.second, actual.second)
 }