JavaPP is a macro processor that runs in the Java VM and resembles the
C preprocessor in syntax and functionality.  The core text processing is
implemented in python and jython is used for running in the Java VM.


 Grammar
================================

Properties
-----------------

    #define prop property value
    #undefine prop
    ${prop}

Properties can be defined when the processor is executed (see Ant task
description) or during processing using #define.  Properties can also
be removed during processing using #undefine.

Property substitution is performed on the text ${prop} and an error is
raised when 'prop' is not defined.

When defining a property, all text following the property identifier
is considered the value.  For example:

  #define var1 "some string of text"

will cause subsequent substitution to contain the double quote characters
and is NOT the same as...

  #define var1 some string of text

Conditions
-----------------

    #if expression [and|or expression]
    [#elif expression [and|or expression]]
    [#else]
    #endif

Conditions can be nested.  Expressions are combined using the
'and', 'or' operators.

Expressions
-----------------

    operand <operator> operand | [!]defined(prop)

Expressions contain an operator and two operands.  The supported
operators are '==', '!=', '<=', '<', '>=', '>'.  The operand can
be either string literal (surrounded with double quotes), number
(integer or decimal), or property substitution in the form ${prop}.

The special expression 'defined(prop)' is supported for testing
if a given property has been defined.  The alternate syntax
'!defined(prop)' can be used to test if a property is not defined.


 Ant task
================================
To use the ant task, put the javapp.jar file where ant can find it
(eg: ANT_HOME/lib) and add the taskdef to your build script:

<taskdef resource="javapp-defs.xml" />

Or put javapp.jar into your project and specify the classpath in the taskdef:

<taskdef resource="javapp-def.xml" classpath="javapp.jar" />

Attributes
-----------------

srcfile    - input file, either srcfile or nested fileset is required
destfile   - output file, only allowed when srcfile is set
destdir    - destination directory, required for nested source filesets
prefix     - change the macro prefix, default is '#'
inheritall - inherit all properties from the project, default is true
verbose    - show verbose output, default is false

Elements
-----------------

<property> - append key/value pairs to the processors environment
<fileset>  - zero or more filesets of source files


 ToDo
================================
On the list of things to do is:
 * the #include directive
 * custom macros written in python