Class that orchestrates preprocessing p5 syntax into straight Java.
Current Preprocessor Subsitutions:
Other preprocessor functionality
- any function not specified as being protected or private will
be made 'public'. this means that void setup() becomes
public void setup(). This is important to note when
coding with core.jar outside of the PDE.
- compiler.substitute_floats (currently "substitute_f")
treat doubles as floats, i.e. 12.3 becomes 12.3f so that people
don't have to add f after their numbers all the time since it's
confusing for beginners.
- compiler.enhanced_casting byte(), char(), int(), float()
works for casting. this is basic in the current implementation, but
should be expanded as described above. color() works similarly to int(),
however there is also a *function* called color(r, g, b) in p5.
- compiler.color_datatype 'color' is aliased to 'int'
as a datatype to represent ARGB packed into a single int, commonly
used in p5 for pixels and other color operations. this is just a
search/replace type thing, and it can be used interchangeably with int.
- compiler.web_colors (currently "inline_web_colors")
color c = #cc0080; should unpack to 0xffcc0080 (the ff at the top is
so that the color is opaque), which is just an int.
- detects what 'mode' the program is in: static (no function
brackets at all, just assumes everything is in draw), active
(setup plus draw or loop), and java mode (full java support).
The PDE Preprocessor is based on the Java Grammar that comes with
ANTLR 2.7.2. Moving it forward to a new version of the grammar
shouldn't be too difficult.
Here's some info about the various files in this directory:
this is the ANTLR grammar for Java 1.3/1.4 from the
ANTLR distribution. It is in the public domain. The only change to
this file from the original this file is the uncommenting of the
clauses required to support assert().
this describes the Abstract Syntax Tree (AST)
generated by java.g. It is only here as a reference for coders hacking
on the preprocessor, it is not built or used at all. Note that pde.g
overrides some of the java.g rules so that in PDE ASTs, there are a
few minor differences. Also in the public domain.
this is the grammar and lexer for the PDE language
itself. It subclasses the java.g grammar and lexer. There are a couple
of overrides to java.g that I hope to convince the ANTLR folks to fold
back into their grammar, but most of this file is highly specific to
this class traverses the AST generated by
the PDE Recognizer, and emits it as Java code, doing any necessary
transformations along the way. It is based on JavaEmitter.java,
available from antlr.org, written by Andy Tripp ,
who has given permission for it to be distributed under the GPL.
ExtendedCommonASTWithHiddenTokens.java: this adds a necessary
initialize() method, as well as a number of methods to allow for XML
serialization of the parse tree in a such a way that the hidden tokens
are visible. Much of the code is taken from the original
CommonASTWithHiddenTokens class. I hope to convince the ANTLR folks
to fold these changes back into that class so that this file will be
TokenStreamCopyingHiddenTokenFilter.java: this class provides
TokenStreamHiddenTokenFilters with the concept of tokens which can be
copied so that they are seen by both the hidden token stream as well
as the parser itself. This is useful when one wants to use an
existing parser (like the Java parser included with ANTLR) that throws
away some tokens to create a parse tree which can be used to spit out
a copy of the code with only minor modifications. Partially derived
from ANTLR code. I hope to convince the ANTLR folks to fold this
functionality back into ANTLR proper as well.
whitespace_test.pde: a torture test to ensure that the
preprocessor is correctly preserving whitespace, comments, and other
hidden tokens correctly. See the comments in the code for details about
how to run the test.
All other files in this directory are generated at build time by ANTLR
itself. The ANTLR manual goes into a fair amount of detail about the
what each type of file is for.
Hacked to death in 2010 by