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Adobe donated the source code to the Falcon compiler as revision 1383121 on September 10, 2012. It currently lives at incubator/flex/falcon/trunk
. A development branch at incubator/{flex/falcon/branches/develop}} will follow after the build scripts have been tested and debugged.
The ActionScript side of Falcon is of shipping near-shippable quality and is was the basis for Flash Builder 4.7 Preview 1. The rest of Falcon (MXML, CSS, FXG, PROPERTIES) is pre-alpha quality and not ready for production use. Nevertheless, Falcon already supports enough of MXML to compile a correctly-running version of Checkinapp, the test app that is part of the SDK. (Exception: Checkinapp uses one Repeater tag, which is not yet implemented.) The main areas where Falcon needs more work are databinding, states, MXML-specific error reporting, and ASDoc generation.
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- It should compile faster for both full and incremental compiles, especially for multi-project workspaces.
- It should require less memory, especially for multi-project workspaces.
- It should be useful as a code-intelligence engine and incremental compiler for an integrated development environment, and not just as a command-line compiler.
- It should have a design that is easy to understand and to evolve.
- It should generate better bytecode for improved runtime performance.
Source Code
The Falcon trunk 'develop' branch is now available in Apache's Subversion GIT repository at https://
svngit-wip-us.apache.org/repos/asf
/incubator/flex
/falcon/trunk-falcon.git
. You can download it with any Subversion GIT client.
Binary Distributions
No binary distributions are available. Perhaps someone will volunteer to set up automated builds and a build download page?
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Setup for Falcon
Falcon is written in Java 1.6. Its build scripts use Ant 1.7.1. Eclipse projects for development use Eclipse 4.2 (Juno).
The Ant script downloads several third-party JARs. One third-party JAR must be installed as a prerequisite. See the README file for more information.
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You must obtain JFlex 1.4.3 as a prerequisite and set the environment variable JFLEX_JAR
to point to JFlex.jar
. You can obtain JFlex here.
Building Falcon
The top-level Ant script currently has the following targets:
Target | Purpose |
---|---|
javadoc | Builds Falcon's Javadoc at |
eclipse | Prepares or updates the project for use in Eclipse. This takes care of generating the Java code for the lexers, parsers, and BURMs. |
main (default) | Produces an SDK at |
clean | Cleans the build output but leaves any downloaded JARs. |
wipe | Wipes out everything that didn't come from GIT. |
The main
, eclipse
, or javadoc
target will do a one-time download of five third party JARs:
lib/antlr.jar
lib/commons-cli.jar
lib/commons-io.jar
lib/guava.jar
lib/lzma-sdk.jar
Occasionally one of these downloads hangs. Just interrupt Ant and try again. These JARs will remain in the lib
directory until you do a wipe
.
If you do ant -q main
(where the -q
switch means "quiet" and turns off a lot of noisy output), the output the first time should look like this:
No Format |
---|
$ ant -q
[echo] JFLEX_JAR is d:/jflex-1.4.3/jflex/lib/JFlex.jar
[echo] Obtaining lib/antlr.jar
[echo] Obtaining lib/commons-cli.jar
[echo] Obtaining lib/commons-io.jar
[echo] Obtaining lib/guava.jar
[echo] Obtaining lib/jburg.jar
[echo] Obtaining lib/lzma.jar
[echo] Building lib/lzma.jar
[echo] Generating RawASTokenizer
[echo] Generating RawASDocTokenizer
[echo] Generating RawMXMLTokenizer
[echo] Generating ASParser and ASTokenTypes
[antlr] ANTLR Parser Generator Version 2.7.7 (20060906) 1989-2005
[echo] Generating MetadataParser and MetadataTokenTypes
[antlr] ANTLR Parser Generator Version 2.7.7 (20060906) 1989-2005
[echo] Generating CSSLexer and CSSParser
[echo] Generating CSSTree
[echo] Generating CmcEmitter
[echo] Generating CSSEmitter
[echo] Compiling Java code
[echo] Creating generated/dist/sdk/lib/compiler.jar
[echo] Creating generated/dist/sdk/lib/falcon-asc.jar
[echo] Creating generated/dist/sdk/lib/falcon-mxmlc.jar
[echo] Creating generated/dist/sdk/lib/falcon-compc.jar
[echo] Creating generated/dist/sdk/lib/falcon-optimizer.jar
[echo] Creating generated/dist/sdk/lib/falcon-swfdump.jar
[echo] Creating lib/aet.jar
[echo] Creating generated/dist/sdk/lib/flexTasks.jar
[echo] Copying Apache SDK
[echo] Building support.swc
[echo] compiler main completed on 09/14/2012 11:32:37 PM
BUILD SUCCESSFUL
Total time: 1 minute 16 seconds
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From this you can see that the overall flow of the build is
- Download the necessary third-party JAR files.
- Generate Java-based lexer classes from JFlex
.lex
files, Java-based parser classes from ANTLR.g
files, and Java-based BURM classes from JBurg.jbg
files. - Compile the Java code (both the code that's in GIT and the lexers/parsers/BURMs that are generated by the previous step).
- Create the JAR files that are the Falcon deliverables.
- Create a SWC file that needs to be used when compiling Flex with Falcon (because Falcon generates different code for CSS than the old compiler).
All the compiled Java classes that comprise Falcon are packaged as falconcompiler.jar
, which is generated at generated/dist/sdk/lib
. Other JAR files such as falcon-mxmlc.jar
and falcon-compc.jar
are codeless launcher JARs which serve only to run a particular entry point within Falcon. Launchers such as the shell script mxmlc
or the batch file mxmlc.bat
simply run these launch JARs from the command line.
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- Keep the Java warnings in the Eclipse project(s) at 0.
- Keep the 'ant javadoc' warnings at 0.
- Provide Javadoc for new non-private APIs.
- Not change the public API surface (to ease possible re-integration into Flash Builder).
- Pass whatever tests are part of '
ant tests
', once we have some tests.
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Q: Where is the specification for ActionScript ByteCode (ABC)?
A: http://www.adobe.com/content/dam/Adobe/en/devnet/actionscript/articles/avm2overview.pdf
Q: What is a semantic checker?
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