IsRequired function is added. (#12)

Fixes #11

README.md

@@ -8,7 +8,7 @@ There are many validation libraries available, but I prefer to build my own tool
 
 To get started, install the Checker library with the following command:
 
-```golang
+```bash
 go get github.com/cinar/checker
 ```
 
@@ -37,7 +37,7 @@ if !valid {
 }
 ```
 
-### Validating Individual User Data
+### Validating Individual User Input
 
 If you do not want to validate user input stored in a struct, you can individually call the checker functions to validate the user input. Here is an example:
 
@@ -66,4 +66,4 @@ type Person struct {
 
 This package currently provides the following checkers:
 
-- [required]() checks if the required value is provided.
+- [required](docs/checkers/required.md) checks if the required value is provided.

check_required.go

@@ -5,12 +5,17 @@ import "reflect"
 // ResultRequired indicates that the required value is missing.
 const ResultRequired Result = "REQUIRED"
 
+// IsRequired checks if the given required value is present.
+func IsRequired(v interface{}) Result {
+	return checkRequired(reflect.ValueOf(v), reflect.ValueOf(nil))
+}
+
 // makeRequired makes a checker function for required.
 func makeRequired(_ string) CheckFunc {
 	return checkRequired
 }
 
-// checkRequired checks if the required value is provided.
+// checkRequired checks if the required value is present.
 func checkRequired(value, _ reflect.Value) Result {
 	if value.IsZero() {
 		return ResultRequired

check_required_test.go

@@ -5,6 +5,14 @@ import (
 	"testing"
 )
 
+func TestIsRequired(t *testing.T) {
+	s := "valid"
+
+	if IsRequired(s) != ResultValid {
+		t.Fail()
+	}
+}
+
 func TestCheckRequiredValidString(t *testing.T) {
 	s := "valid"
 

doc/checkers/required.md

@@ -0,0 +1,27 @@
+# Required Checker
+
+The ```required``` checker checks for the presence of required input. If the input is not present, the checker will return the ```REQUIRED``` result. Here is an example:
+
+```golang
+type Person struct {
+    Name string `checkers:"required"`
+}
+
+person := &Person{}
+
+mistakes, valid := checker.Check(person)
+if !valid {
+    // Send the mistakes back to the user
+}
+```
+
+If you do not want to validate user input stored in a struct, you can individually call the ```required``` checker function ```IsRequired``` to validate the user input. Here is an example:
+
+```golang
+var name
+
+result := checker.IsRequired(name)
+if result != ResultValid {
+    // Send the result back to the user
+}
+```