Revised after review

* Dropped 'script' support
* Improved documentation
* Made pathFn members private

doc_test.go

@@ -0,0 +1,51 @@
+// code examples for godoc
+
+package toml
+
+import "fmt"
+
+func ExampleNodeFilterFn_filterExample() {
+	tree, _ := Load(`
+      [struct_one]
+      foo = "foo"
+      bar = "bar"
+
+      [struct_two]
+      baz = "baz"
+      gorf = "gorf"
+    `)
+
+	// create a query that references a user-defined-filter
+	query, _ := CompileQuery("$[?(bazOnly)]")
+
+	// define the filter, and assign it to the query
+	query.SetFilter("bazOnly", func(node interface{}) bool {
+		if tree, ok := node.(*TomlTree); ok {
+			return tree.Has("baz")
+		}
+		return false // reject all other node types
+	})
+
+	// results contain only the 'struct_two' TomlTree
+	query.Execute(tree)
+}
+
+func ExampleQuery_queryExample() {
+	config, _ := Load(`
+      [[book]]
+      title = "The Stand"
+      author = "Stephen King"
+      [[book]]
+      title = "For Whom the Bell Tolls"
+      author = "Ernest Hemmingway"
+      [[book]]
+      title = "Neuromancer"
+      author = "William Gibson"
+    `)
+
+	// find and print all the authors in the document
+	authors, _ := config.Query("$.book.author")
+	for _, name := range authors.Values() {
+		fmt.Println(name)
+	}
+}