 }
 
 /**
-This function is documented with the FilterFunction type.
-
-:see: FilterFunction
+Builds a filter that takes a single `Int` argument.
+
+For example:
+
+    let increment = Filter { (x: Int, _) in
+        return Box(x + 1)
+    }
+
+    let template = Template(string: "{{increment(x)}}")!
+    template.registerInBaseContext("increment", Box(increment))
+
+    // "2"
+    template.render(Box(["x": 1]))!
+
+If the template argument evaluates to a missing value, or a value which is not
+not convertible to Int, the filter returns an error of domain
+`GRMustacheErrorDomain` and code `GRMustacheErrorCodeRenderingError`:
+
+    // Error evaluating {{increment(x)}} at line 1: Unexpected argument
+    var error: NSError?
+    template.render(Box(), error: &error)
+    template.render(Box(["x": "foo"]), error: &error)
+
+Values which are convertible to Int are:
+
+    // "2"
+    template.render(Box(["x": 1]))!                     // Int
+    template.render(Box(["x": 1 as UInt]))!             // UInt
+    template.render(Box(["x": 1.0]))!                   // Double
+    template.render(Box(["x": NSNumber(integer: 1)]))!  // NSNumber
+    template.render(Box(["x": NSNumber(bool: true)]))!  // NSNumber (continued)
+    template.render(Box(["x": true]))!                  // Bool
+
+If the filter is given several arguments, an error of domain
+`GRMustacheErrorDomain` and code `GRMustacheErrorCodeRenderingError` is returned
+when the template is rendered.
+
+:param: a function that turns an integer into a MustacheBox
+:returns: a FilterFunction
 */
 public func Filter(filter: (Int, NSErrorPointer) -> MustacheBox?) -> FilterFunction {
     return { (box: MustacheBox, partialApplication: Bool, error: NSErrorPointer) in

}

/**
This function is documented with the FilterFunction type.

:see: FilterFunction
*/
public func Filter<T>(filter: (T?, NSErrorPointer) -> MustacheBox?) -> FilterFunction {
    return { (box: MustacheBox, partialApplication: Bool, error: NSErrorPointer) in



/**
Builds a filter that takes a single argument.

For example, here is the trivial `identity` filter:

