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/*
* Copyright © 2002 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
* California 95054, U.S.A. All rights reserved. Sun Microsystems, Inc. has
* intellectual property rights relating to technology embodied in the product
* that is described in this document. In particular, and without limitation,
* these intellectual property rights may include one or more of the U.S.
* patents listed at http://www.sun.com/patents and one or more additional
* patents or pending patent applications in the U.S. and in other countries.
* U.S. Government Rights - Commercial software. Government users are subject
* to the Sun Microsystems, Inc. standard license agreement and applicable
* provisions of the FAR and its supplements. Use is subject to license terms.
* Sun, Sun Microsystems, the Sun logo and Java are trademarks or registered
* trademarks of Sun Microsystems, Inc. in the U.S. and other countries. This
* product is covered and controlled by U.S. Export Control laws and may be
* subject to the export or import laws in other countries. Nuclear, missile,
* chemical biological weapons or nuclear maritime end uses or end users,
* whether direct or indirect, are strictly prohibited. Export or reexport
* to countries subject to U.S. embargo or to entities identified on U.S.
* export exclusion lists, including, but not limited to, the denied persons
* and specially designated nationals lists is strictly prohibited.
*/
JJTreeExamples
This directory contains some simple JJTree input files intended to
illustrate some of the basic ideas. All of them are based on an
grammar to recognize arithmetic expressions built out of identifiers
and constants.
eg1.jjt
This example is just the JavaCC grammar, with a little extra code in
the parser's main method to call the dump method on the generated
tree. It illustrates how the default behavior of JJTree will produce
a tree of non-terminals.
eg2.jjt
This example is the same grammar as eg1.jjt with modifications to
customize the generated tree. It illustrates how unnecessary
intermediate nodes can be suppressed, and how actions in the grammar
can attach extra information to the nodes.
eg3.jjt
This example is a modification of eg2.jjt with the NODE_DEFAULT_VOID
option set. This instructs JJTree to treat all undecorated
non-terminals as if they were decorated as #void. The default JJTree
behavior is to treat such non-terminals as if they were decorated
with the name of the non-terminal.
eg4.jjt
This is a modification of eg3.jjt with the VISITOR option set. This
instructs JJTree to insert a jjtAccept() method into all nodes it
generates, and to produce a visitor class. The visitor is used to
dump the tree.
Here are some instructions on how to run the examples and the output
you can expect to see.
eg1.jjt
-------
The only bit of JJTree-specific code is an action in the start
production that dumps the constructed parse tree when the parse is
complete. It uses JJTree simple mode.
The input file is eg1.jjt.
trane% jjtree eg1.jjtJava Compiler Compiler Version 2.0 (Tree Builder)
Copyright (c) 1996-1999 Sun Microsystems, Inc.
Copyright (c) 1997-1999 Metamata, Inc.
(type "jjtree" with no arguments for help)
Reading from file eg1.jjt . . .File "Node.java" does not exist. Will create one.
File "SimpleNode.java" does not exist. Will create one.
Annotated grammar generated successfully in eg1.jj
trane%
JJTree has now generated the JavaCC parser source, as well as Java
source for the parse tree node building classes. Running JavaCC in
the normal way generates the remaining Java code.
trane% javacc eg1.jj
Java Compiler Compiler Version 2.0 (Parser Generator)
Copyright (c) 1996-1999 Sun Microsystems, Inc.
Copyright (c) 1997-1999 Metamata, Inc.
(type "javacc" with no arguments for help)
Reading from file eg1.jj . . .
File "TokenMgrError.java" does not exist. Will create one.
File "ParseException.java" does not exist. Will create one.
File "Token.java" does not exist. Will create one.
File "ASCII_CharStream.java" does not exist. Will create one.
Parser generated successfully.
trane%
Compile and run the Java as usual. The expression is read from the
standard input (you type in "(a + b) * (c + 1);"):
trane% javac eg1.java
trane% java eg1
Reading from standard input...
(a + b) * (c + 1);
Start
Expression
AdditiveExpression
MultiplicativeExpression
UnaryExpression
Expression
AdditiveExpression
MultiplicativeExpression
UnaryExpression
Identifier
MultiplicativeExpression
UnaryExpression
Identifier
UnaryExpression
Expression
AdditiveExpression
MultiplicativeExpression
UnaryExpression
Identifier
MultiplicativeExpression
UnaryExpression
Integer
Thank you.
trane%
eg2.jjt
-------
This is a modification of the first example to illustrate how the
parse tree can be customized:
trane% jjtree eg2.jjt
Java Compiler Compiler Version 2.0 (Tree Builder)
Copyright (c) 1996-1999 Sun Microsystems, Inc.
Copyright (c) 1997-1999 Metamata, Inc.
(type "jjtree" with no arguments for help)
Reading from file eg2.jjt . . .
File "Node.java" does not exist. Will create one.
File "SimpleNode.java" does not exist. Will create one.
File "ASTStart.java" does not exist. Will create one.
File "ASTAdd.java" does not exist. Will create one.
File "ASTMult.java" does not exist. Will create one.
File "ASTInteger.java" does not exist. Will create one.
Annotated grammar generated successfully in eg2.jj
trane%
trane% javacc eg2.jj
Java Compiler Compiler Version 2.0 (Parser Generator)
Copyright (c) 1996-1999 Sun Microsystems, Inc.
Copyright (c) 1997-1999 Metamata, Inc.
(type "javacc" with no arguments for help)
Reading from file eg2.jj . . .
File "TokenMgrError.java" does not exist. Will create one.
File "ParseException.java" does not exist. Will create one.
File "Token.java" does not exist. Will create one.
File "ASCII_CharStream.java" does not exist. Will create one.
Parser generated successfully.
trane%
trane% javac eg2.java
trane% java eg2
Reading from standard input...
(a + b) * (c + 1);
Start
Mult
Add
Identifier: a
Identifier: b
Add
Identifier: c
Integer
Thank you.
trane%
Look at eg2.jjt to see how node annotations can be used to restructure
the parse tree, and at ASTMyID.java to see how you can write your own
node classes that maintain more information from the input stream.
eg3.jjt
-------
This example can be run in the same manner as you ran eg2.jjt.
eg4.jjt
-------
This example again can be run in the same manner as you ran eg2.jjt.
One thing to take care in this case is that you must run jjtree on
a clean directory (that does not contain previously generated files).
For example, the file SimpleNode.java is different when the option
VISITOR is set to true.
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