Add implementation for HTML Token sanitizing policy

Sources/HTMLTokenPolicy.h

@@ -7,7 +7,16 @@
 //
 
 #import <Foundation/Foundation.h>
+#import "HTMLTokens.h"
+
+NS_ASSUME_NONNULL_BEGIN
 
 @interface HTMLTokenPolicy : NSObject
 
++ (instancetype)policy:(nullable HTMLToken * (^)(HTMLToken *))block;
+
+- (nullable HTMLToken *)apply:(HTMLToken *)token;
+
 @end
+
+NS_ASSUME_NONNULL_END

Sources/HTMLTokenPolicy.m

@@ -8,6 +8,31 @@
 
 #import "HTMLTokenPolicy.h"
 
+@interface HTMLTokenPolicy()
+{
+	HTMLToken * (^ _policyBlock)(HTMLToken *);
+}
+@end
+
 @implementation HTMLTokenPolicy
 
++ (instancetype)policy:(HTMLToken * _Nullable (^)(HTMLToken * _Nonnull))block
+{
+	return [[HTMLTokenPolicy alloc] initWithBlock:block];
+}
+
+- (instancetype)initWithBlock:(HTMLToken * _Nullable (^)(HTMLToken * _Nonnull))block
+{
+	self = [super init];
+	if (self) {
+		_policyBlock = block;
+	}
+	return self;
+}
+
+- (HTMLToken *)apply:(HTMLToken *)token
+{
+	return _policyBlock(token);
+}
+
 @end