com.google.template.soy.passes

Class HtmlRewritePass

java.lang.Object

com.google.template.soy.passes.CompilerFilePass

com.google.template.soy.passes.HtmlRewritePass

public final class HtmlRewritePass
extends CompilerFilePass

Rewrites templates and blocks of kind="html" or kind="attributes" to contain HtmlOpenTagNode, HtmlCloseTagNode, HtmlAttributeNode, and HtmlAttributeValueNode.

The strategy is to parse the raw text nodes for html tokens and then trigger AST rewriting based on what we find.

An obvious question upon reading this should be "Why isn't this implemented in the grammar?" the answer is that soy has some language features that interfere with writing such a grammar.

• Soy has special commands for manipulating text, notably: {nil}, {sp}, {\n} cause difficulties when writing grammar productions for html elements. This would be manageable by preventing the use of these commands within html tags (though some of them such as {sp} are popular so there are some compatibility concerns)
• Soy has a {literal}...{/literal} command. such commands often contain html tags so within the grammar we would need to start writing grammar production which match the contents of literal blocks. This is possible but would require duplicating all the lexical states for literals. (Also we would need to deal with tags split across literal blocks e.g. {/literal}).
• Transitioning between lexical states after seeing a <script> tag or after parsing a kind="html" attributes is complex (And 'semantic lexical transitions' are not recommended).

On the other hand by implementing this here, a lot of these issues go away since all the text has already been processed. Of course this doesn't mean it is easy since we need to implement our own parser and state tracking system that is normally handled by the javacc grammar.

This class tries to be faithful to the Html syntax standard. Though we do not attempt to implement the contextual element model, and matching tags is handled by a different pass, the StrictHtmlValidationPass.

Constructor Summary

Constructors

Constructor and Description
HtmlRewritePass(ErrorReporter errorReporter)

Method Summary

Modifier and Type	Method and Description
void	run(SoyFileNode file, IdGenerator nodeIdGen)

Methods inherited from class com.google.template.soy.passes.CompilerFilePass

name, toString

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

HtmlRewritePass

public HtmlRewritePass(ErrorReporter errorReporter)

Parameters:

errorReporter - The error reporter

Method Detail

run

public void run(SoyFileNode file,
                IdGenerator nodeIdGen)

Specified by:

run in class CompilerFilePass