JJTree Task

JJTree

Description

Invokes the JJTree preprocessor for the JavaCC compiler compiler. It inserts parse tree building actions at various places in the JavaCC source that it generates. The output of JJTree is run through JavaCC to create the parser.

To use the jjtree task, set the target attribute to the name of the JJTree grammar file to process. You also need to specify the directory containing the JavaCC installation using the javacchome attribute, so that ant can find the JavaCC classes. Optionally, you can also set the outputdirectory to write the generated JavaCC grammar and node files to a specific directory. Otherwise jjtree writes the generated JavaCC grammar and node files to the directory containing the JJTree grammar file. As an extra option, you can also set the outputfile to write the generated JavaCC grammar file to a specific (directory and) file. Otherwise jjtree writes the generated JavaCC grammar file as the JJTree grammar file with a suffix .jj.

This task only invokes JJTree if the grammar file is newer than the generated JavaCC file.

Parameters

Attribute	Description	Required
target	The jjtree grammar file to process.	Yes
javacchome	The directory containing the JavaCC distribution.	Yes
outputdirectory	The directory to write the generated JavaCC grammar and node files to. If not set, the files are written to the directory containing the grammar file.	No
outputfile	The file to write the generated JavaCC grammar file to. If not set, the file is written with the same name as the JJTree grammar file but with a the suffix `.jj`. This is a filename relative to outputdirectory if specified, the project's basedir.	No
buildnodefiles	Sets the BUILD_NODE_FILES grammar option. This is a boolean option.	No
multi	Sets the MULTI grammar option. This is a boolean option.	No
nodedefaultvoid	Sets the NODE_DEFAULT_VOID grammar option. This is a boolean option.	No
nodefactory	Sets the NODE_FACTORY grammar option. This is boolean option.	No
nodescopehook	Sets the NODE_SCOPE_HOOK grammar option. This is a boolean option.	No
nodeusesparser	Sets the NODE_USES_PARSER grammar option. This is a boolean option.	No
static	Sets the STATIC grammar option. This is a boolean option.	No
visitor	Sets the VISITOR grammar option. This is a boolean option.	No
nodepackage	Sets the NODE_PACKAGE grammar option. This is a string option.	No
visitorexception	Sets the VISITOR_EXCEPTION grammar option. This is a string option.	No
nodeprefix	Sets the NODE_PREFIX grammar option. This is a string option.	No

Example

<jjtree 
    target="src/Parser.jjt" 
    outputdirectory="build/src"
    javacchome="c:/program files/JavaCC" 
    nodeusesparser="true"
/>

This invokes JJTree on grammar file src/Parser.jjt, writing the generated grammar file, Parser.jj, file to build/src. The grammar option NODE_USES_PARSER is set to true when invoking JJTree.