// Copyright 2011 The Go Authors. All rights reserved. // Use of this source code is governed by a BSD-style // license that can be found in the LICENSE file. package html import ( "bufio" "errors" "fmt" "io" "strings" ) type writer interface { io.Writer io.ByteWriter WriteString(string) (int, error) } // Render renders the parse tree n to the given writer. // // Rendering is done on a 'best effort' basis: calling Parse on the output of // Render will always result in something similar to the original tree, but it // is not necessarily an exact clone unless the original tree was 'well-formed'. // 'Well-formed' is not easily specified; the HTML5 specification is // complicated. // // Calling Parse on arbitrary input typically results in a 'well-formed' parse // tree. However, it is possible for Parse to yield a 'badly-formed' parse tree. // For example, in a 'well-formed' parse tree, no element is a child of // another element: parsing "" results in two sibling elements. // Similarly, in a 'well-formed' parse tree, no element is a child of a //

element: parsing "

" results in a

with two sibling // children; the is reparented to the

's parent. However, calling // Parse on "

" does not return an error, but the result has an // element with an child, and is therefore not 'well-formed'. // // Programmatically constructed trees are typically also 'well-formed', but it // is possible to construct a tree that looks innocuous but, when rendered and // re-parsed, results in a different tree. A simple example is that a solitary // text node would become a tree containing
, and
elements. // Another example is that the programmatic equivalent of "abc" // becomes "
abc