Add check.IsNul to catch stupid nil interface err

check/check.go

@@ -1,5 +1,7 @@
 package check
 
+import "reflect"
+
 // Blank checks that the passed string, []byte (or slice of either)
 // contains something besides an empty string.
 func Blank(i interface{}) bool {
@@ -19,3 +21,10 @@ func Blank(i interface{}) bool {
 	}
 	return false
 }
+
+// IsNil is a shortcut for reflect.ValueOf(foo).IsNil() and should only
+// be used when foo == nil is in question, such as whenever the value of
+// foo is an interface of any kind. In fact, every interface should use
+// this check instead just to be sure to avoid surprise (and extremely
+// odd) logic errors. Nil is not "nil" in Go.
+func IsNil(i interface{}) bool { return reflect.ValueOf(i).IsNil() }

check/check_test.go

@@ -2,6 +2,7 @@ package check_test
 
 import (
 	"fmt"
+	"reflect"
 
 	"github.com/rwxrob/bonzai/check"
 )
@@ -25,3 +26,18 @@ func ExampleBlank() {
 	// true
 	// true
 }
+
+func ExampleIsNil() {
+	var names []string
+	var namesi interface{}
+	namesi = names
+	fmt.Println(names == nil)
+	fmt.Println(namesi == nil)
+	fmt.Println(reflect.ValueOf(namesi).IsNil())
+	fmt.Println(check.IsNil(namesi))
+	// Output:
+	// true
+	// false
+	// true
+	// true
+}