THIS IS A TEST INSTANCE. ALL YOUR CHANGES WILL BE LOST!!!!
...
Falcon
...
is
...
a
...
new
...
compiler
...
for
...
Flex
...
that
...
is
...
under
...
development.
...
It
...
will
...
eventually
...
replace
...
the
...
legacy
...
compiler
...
that
...
has
...
been
...
part
...
of
...
the
...
Flex
...
SDK.
...
Current
...
Status
...
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
...
near-shippable
...
quality
...
and
...
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.
...
Gordon
...
Smith
...
of
...
Adobe,
...
who
...
has
...
worked
...
on
...
Falcon
...
from
...
the
...
beginning
...
of
...
the
...
Falcon
...
project,
...
is
...
on
...
loan
...
to
...
Apache
...
Flex
...
for
...
one
...
day
...
a
...
week
...
to
...
improve
...
Falcon's
...
MXML
...
support,
...
with
...
the
...
goal
...
of
...
making
...
it
...
a
...
suitable
...
replacement
...
for
...
the
...
legacy
...
compiler.
...
He
...
will
...
provide
...
advice
...
to
...
Apache
...
developers
...
contributing
...
to
...
Falcon.
...
Alex
...
Harui
...
of
...
Adobe
...
has
...
become
...
familiar
...
with
...
MXML
...
code
...
generation
...
in
...
Falcon
...
and
...
can
...
offer
...
advice
...
in
...
that
...
area.
...
Everyone
...
can
...
contribute
...
to
...
Falcon's
...
development
...
by
...
using
...
it
...
to
...
compile
...
their
...
Flex
...
applications
...
and
...
reporting
...
any
...
bugs
...
you
...
find
...
in
...
Jira.
...
Reducing
...
a
...
bug
...
to
...
a
...
simple
...
test
...
case
...
will
...
make
...
it
...
infinitely
...
more
...
likely
...
to
...
be
...
fixed.
...
The
...
following
...
initial
...
development
...
efforts
...
are
...
planned:
...
- Run
...
- the
...
- source
...
- code
...
- for
...
- all
...
- Apache
...
- Flex
...
- SWCs
...
- through
...
- Falcon
...
- to
...
- see
...
- if
...
- spurious
...
- problems
...
- are
...
- reported.
...
- Update
...
- the
...
- source
...
- code
...
- as
...
- necessary,
...
- given
...
- the
...
- fact
...
- that
...
- Falcon
...
- is
...
- somewhat
...
- stricter
...
- than
...
- the
...
- legacy
...
- compiler.
...
- It
...
- should
...
- be
...
- possible
...
- to
...
- make
...
- both
...
- compilers
...
- happy.
...
- Get
...
- various
...
- test
...
- apps
...
- besides
...
- Checkinapp
...
- compiling,
...
- linking
...
- against
...
- Falcon-compiled
...
- SWCs,
...
- and
...
- running
...
- correctly.
...
- Get
...
- Mustella
...
- tests
...
- compiling
...
- with
...
- Falcon
...
- and
...
- passing.
...
- Fix
...
- bugs
...
- that
...
- the
...
- Apache
...
- Flex
...
- community
...
- prioritizes.
...
Falcon's
...
Original
...
Goals
...
Falcon
...
had
...
the
...
following
...
goals
...
when
...
the
...
project
...
was
...
started.
...
Compared
...
with
...
the
...
legacy
...
compiler,
...
- 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
...
is
...
now
...
available
...
in
...
Apache's
...
Subversion
...
repository
...
at
...
https://svn.apache.org/repos/asf/incubator/flex/falcon/trunk
.
...
You
...
can
...
download
...
it
...
with
...
any
...
Subversion
...
client.
...
Binary
...
Distributions
...
No
...
binary
...
distributions
...
are
...
available.
...
Perhaps
...
someone
...
will
...
volunteer
...
to
...
set
...
up
...
automated
...
builds
...
and
...
a
...
build
...
download
...
page?
...
Building
...
Falcon
...
Falcon
...
is
...
written
...
in
...
Java
...
1.6.
...
Its
...
build
...
scripts
...
use
...
Ant
...
1.7.
...
Eclipse
...
projects
...
for
...
development
...
use
...
Eclipse
...
4.2
...
(Juno).
...
The
...
top-level
...
Ant
...
script
...
has
...
the
...
following
...
targets:
...
Target | Purpose |
|---|---|
javadoc | Builds Falcon's |
...
Javadoc. |
...
See |
...
the |
...
Javadoc |
...
section |
...
below |
...
for |
...
more |
...
information. |
...
eclipse | Prepares 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 the downloaded JARs. |
wipe | Wipes out everything that didn't come from Subversion. |
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.
Information about Ant targets will be available soon.
All the compiled Java classes that comprise Falcon are packaged as falcon.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.
...
Because
...
Falcon
...
requires
...
a
...
number
...
of
...
other
...
files
...
(such
...
as
...
flex-config.xml
...
,
...
framework.swc
...
,
...
etc.)
...
to
...
compile
...
anything,
...
the
...
Falcon
...
build
...
script
...
actually
...
creates
...
a
...
small
...
SDK
...
in
...
which
...
everything
...
is
...
arranged
...
so
...
that
...
tools
...
like
...
Falcon's
...
mxmlc
...
work
...
the
...
way
...
they
...
would
...
if
...
they
...
were
...
in
...
an
...
actual
...
Apache
...
Flex
...
SDK.
...
This
...
"Falcon
...
SDK"
...
is
...
built
...
at
...
generated/dist/sdk
...
.
Committing to Falcon
Each commit to the trunk will be expected to:
- 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.
...
Using
...
Falcon
...
On
...
the
...
Command
...
Line
...
The
...
bin
...
folder
...
inside
...
generated/dist/sdk
...
has
...
the
...
command-line
...
launchers
...
like
...
mxmlc
...
,
...
so
...
using
...
Falcon
...
is
...
the
...
same
...
as
...
you
...
are
...
used
...
to.
...
For
...
example,
...
if
...
you
...
have
...
but
...
this
...
bin
...
directory
...
on
...
your
...
PATH
...
and
...
you
...
have
...
cd
...
'd
...
to
...
you
...
application
...
directory,
...
then
...
you
...
just
...
do
| No Format |
|---|
} mxmlc MyApp.mxml {noformat} |
The
...
options
...
to
...
the
...
Falcon
...
version
...
of
...
mxmlc
...
are
...
basically
...
the
...
same
...
as
...
for
...
the
...
legacy
...
compiler.
...
Some
...
options
...
such
...
as
...
-keep
...
are
...
no
...
longer
...
supported.
...
If
...
you
...
try
...
use
...
an
...
unsupported
...
options,
...
a
...
warning
...
will
...
let
...
you
...
know.
...
In
...
an
...
Ant
...
Script
...
Like
...
the
...
legacy
...
compiler,
...
Falcon
...
provides
...
<mxmlc>
...
and
...
<compc>
...
Ant
...
tasks.
...
They
...
are
...
implemented
...
by
...
the
...
classes
...
MXMLCTask
...
and
...
COMPCTask
...
in
...
the
...
org.apache.flex.compiler.ant
...
package.
...
These
...
classes
...
are
...
part
...
of
...
falcon.jar
...
.
...
To
...
use
...
these
...
tasks
...
in
...
an
...
Ant
...
script,
...
first
...
do
| No Format |
|---|
} <taskdef ???/> {noformat} |
The
...
require
...
that
...
the
...
Ant
...
property
...
FLEX_HOME
...
be
...
set
...
to
...
a
...
Flex
...
SDK
...
directory
...
so
...
that
...
config
...
files
...
and
...
SWC
...
files
...
can
...
be
...
found.
...
Inside
...
Eclipse
...
The
...
relevant
...
entry
...
points
...
for
...
a
...
Debug
...
Configuration
...
are
...
the MXMLC and COMPC classes in the org.apache.flex.compiler.clients
...
package.
...
Inside
...
Flash
...
Builder
...
There
...
is
...
no
...
way
...
to
...
use
...
Apache
...
Falcon
...
inside
...
of
...
Flash
...
Builder,
...
at
...
least
...
for
...
now.
...
Because
...
Falcon
...
is
...
designed
...
to
...
be
...
both
...
a
...
compiler
...
and
...
a
...
code-intelligence
...
engine,
...
it
...
has
...
to
...
be
...
tightly
...
integrated
...
with
...
Flash
...
Builder;
...
Flash
...
Builder
...
cannot
...
load
...
it
...
from
...
an
...
SDK.
...
Testing
...
Falcon
...
Falcon's
...
existing
...
test
...
suites
...
are
...
not
...
yet
...
ready
...
for
...
donation,
...
because
...
they
...
are
...
very
...
large
...
and
...
require
...
more
...
extensive
...
review.
...
They
...
will
...
be
...
donated
...
later.
...
As
...
soon
...
as
...
possible
...
after
...
donation,
...
a
...
handful
...
of
...
tests
...
will
...
be
...
developed
...
to
...
ensure
...
that
...
are
...
still
...
able
...
to
...
compile
...
framework.swc
...
and
...
Checkinapp.
...
These
...
make
...
poor
...
unit
...
tests
...
but
...
reasonable
...
functional
...
tests.
Javadoc
Falcon has reasonably extensive Javadoc, including a short overview and package-level documentation that provides a general orientation to various subsystems. The Javadoc is not currently available online. If we get an automated build for Falcon, we may start posting Javadoc.
To build the Javadoc, download the source code and do
| No Format |
|---|
ant javadoc
|
in the compiler directory within Falcon's trunk. The generated HTML is inside generated/javadoc within Falcon's trunk. Open index.html in any browser and start by clicking on the Description link at the top to see the overview.
History
Spring 2010
Falcon began as a project at Adobe in response to the Flex community's concerns about long compilation times with the legacy compiler. The project began with several months of discussions about improving the old compiler versus starting over with Falcon. The main reasons for starting over were:
*The compiler team at Adobe wanted a compiler that could do double-duty as the code-intelligence engine for Flash Builder, rather than being something completely separate that Flash Builder called just to create a SWF or SWC. This approach would avoid duplicate data structures and duplicate algorithms, and would enable live error highlighting based on accurate semantic analysis. The team ended up taking Flash Builder's code intelligence engine, improving it, and adding semantic analysis and code generation to it. The resulting Falcon compiler doesn't have dependencies on Flash Builder though... it's the other way around.
*The legacy compiler wasn't designed for compilation on multiple threads. The team wanted a compiler that was designed with concurrency in mind from the beginning, as a primary way to get better – and scalable – performance.
*There was an awkward relationship between the legacy asc (which essentially understands only how to compile a single .as file) and the legacy mxmlc (which layers on top multi-file compilation and support for .mxml, .css, .properties, and .fxg), based on their historical development by two separate teams at Adobe. The team wanted a single compiler, designed by a single team, that had a unified architecture, unified data structures, and multi-file / multi-language support from the bottom up.
Fall 2011
A strategic shift at Adobe resulted a refocus on ActionScript and a defocus on Flex and MXML. Flex was donated to Apache, with a promise to finish the ActionScript side of Falcon and donate it by the end of 2012. Non-ActionScript support was left intact, at pre-alpha quality.
Summer 2012
Falcon was prepared for donation to Apache. By this point it has involved approximately 15 person-years of development effort.
The Future
It's up to us now! However, before striking out in radical new directions we should bring Falcon to the point where it can replace the legacy compiler.
Architecture
Falcon is designed from the beginning to support compiling multiple targets in multiple projects in a workspace, as exist in an IDE like Flash Builder. By contrast, the legacy asc was designed to compile a single AS file, and then the legacy mxmlc was built by another team on top of that.
Falcon uses multiple threads to compile multiple files at the same time. It can even compile multiple method bodies in the same file in parallel. The more cores you have, the faster it goes, unlike the legacy compiler. The multiple threads are managed using Java Futures (java.util.concurrent.IFuture<V>). The maximum number of thread allowed to be used is a small multiple of the number of cores.
Critical data structures such as the symbol table (which stores information about which classes are known, what methods they have, etc.) are shared across the entire workspace, to minimize memory usage.
Critical data structures are maintained in memory to support both compilation and IDE code intelligence in an efficient and consistent way. For example: If you open an ActionScript file in Flash Builder 4.7, Falcon builds a syntax tree and symbol table for it to support intelligent editing. Compiling the file requires just one additional code generation step. By contrast, in Flash Builder 4.6, which uses the legacy compiler in the SDK, the IDE builds its own parse trees and symbol tables to support editing, and then when you compile the compiler in the SDK builds another set of parse trees and symbol tables. This is slow and a waste of memory.
Falcon was designed from the beginning for incremental compilation of a complete workspace, so it tracks dependencies between compilation units in various projects. If you edit a file, it knows which other files it should recompile.
It can compile an app against a library project without creating the SWC for that library on disk.
Falcon understands .as, .mxml, .fxg, .css, and .properties files.
The parse trees for AS consist of nodes from about 100 classes, such as LiteralNode, BinaryOperatorPlusNode, FunctionNode, and ClassNode. The parse trees for MXML consist of nodes from about 50 classes, such as MXMLDocumentNode, MXMLInstanceNode, MXMLScriptNode, etc. The ActionScript-y parts of MXML are represented by AS nodes that are children of MXML nodes.
The symbol table consists of objects representing the things your code defines, such as ClassDefinition, FunctionDefinition, and VariableDefinition. These are stored in scope objects which form a hierarchy reflecting the lexical blocks of the source code.
Falcon uses third-party grammars like JFlex, ANTLR, and JBurg to generate various lexers, parsers, and code generators. The lexers for AS and MXML are written in JFlex .lex files. The lexer for CSS, and the parsers for AS, MXML, and CSS, are written in ANTLR .g files. The code generator is written in JBurg .jbg files. JBurg is a Java implementation of a Bottom-Up Rewrite Generator (BURG) which generates Java code for a Bottom-Up-Rewrite Machine (BURM). The BURM uses patterns and rules to find subtrees within in an abstract syntax tree that it can "reduce" to an intermediate form, typically a sequence of bytecode instructions. The process continues until the entire tree is reduced to ABC, which goes into a DoABC tag of a SWF file.
The typical data flow for an AS file is
| No Format |
|---|
h2. Javadoc Falcon has reasonably extensive Javadoc, including a short overview and package-level documentation that provides a general orientation to various subsystems. The Javadoc is not currently available online. If we get an automated build for Falcon, we may start posting Javadoc. To build the Javadoc, download the source code and do {noformat} ant javadoc {noformat} in the {{compiler}} directory within Falcon's trunk. The generated HTML is inside {{generated/javadoc}} within Falcon's trunk. Open {{index.html}} in any browser and start by clicking on the Description link at the top to see the overview. h2. History h4. Spring 2010 Falcon began as a project at Adobe in response to the Flex community's concerns about long compilation times with the legacy compiler. The project began with several months of discussions about improving the old compiler versus starting over with Falcon. The main reasons for starting over were: *The compiler team at Adobe wanted a compiler that could do double-duty as the code-intelligence engine for Flash Builder, rather than being something completely separate that Flash Builder called just to create a SWF or SWC. This approach would avoid duplicate data structures and duplicate algorithms, and would enable live error highlighting based on accurate semantic analysis. The team ended up taking Flash Builder's code intelligence engine, improving it, and adding semantic analysis and code generation to it. The resulting Falcon compiler doesn't have dependencies on Flash Builder though... it's the other way around. *The legacy compiler wasn't designed for compilation on multiple threads. The team wanted a compiler that was designed with concurrency in mind from the beginning, as a primary way to get better -- and scalable -- performance. *There was an awkward relationship between the legacy {{asc}} (which essentially understands only how to compile a single {{.as}} file) and the legacy {{mxmlc}} (which layers on top multi-file compilation and support for {{.mxml}}, {{.css}}, {{.properties}}, and {{.fxg}}), based on their historical development by two separate teams at Adobe. The team wanted a single compiler, designed by a single team, that had a unified architecture, unified data structures, and multi-file / multi-language support from the bottom up. h4. Fall 2011 A strategic shift at Adobe resulted a refocus on ActionScript and a defocus on Flex and MXML. Flex was donated to Apache, with a promise to finish the ActionScript side of Falcon and donate it by the end of 2012. Non-ActionScript support was left intact, at pre-alpha quality. h4. Summer 2012 Falcon was prepared for donation to Apache. By this point it has involved approximately 15 person-years of development effort. h4. The Future It's up to us now! However, before striking out in radical new directions we should bring Falcon to the point where it can replace the legacy compiler. h2. Architecture Falcon is designed from the beginning to support compiling multiple targets in multiple projects in a workspace, as exist in an IDE like Flash Builder. By contrast, the legacy {{asc}} was designed to compile a single AS file, and then the legacy {{mxmlc}} was built by another team on top of that. Falcon uses multiple threads to compile multiple files at the same time. It can even compile multiple method bodies in the same file in parallel. The more cores you have, the faster it goes, unlike the legacy compiler. The multiple threads are managed using Java Futures ({{java.util.concurrent.IFuture<V>}}). The maximum number of thread allowed to be used is a small multiple of the number of cores. Critical data structures such as the symbol table (which stores information about which classes are known, what methods they have, etc.) are shared across the entire workspace, to minimize memory usage. Critical data structures are maintained in memory to support both compilation and IDE code intelligence in an efficient and consistent way. For example: If you open an ActionScript file in Flash Builder 4.7, Falcon builds a syntax tree and symbol table for it to support intelligent editing. Compiling the file requires just one additional code generation step. By contrast, in Flash Builder 4.6, which uses the legacy compiler in the SDK, the IDE builds its own parse trees and symbol tables to support editing, and then when you compile the compiler in the SDK builds another set of parse trees and symbol tables. This is slow and a waste of memory. Falcon was designed from the beginning for incremental compilation of a complete workspace, so it tracks dependencies between compilation units in various projects. If you edit a file, it knows which other files it should recompile. It can compile an app against a library project without creating the SWC for that library on disk. Falcon understands {{.as}}, {{.mxml}}, {{.fxg}}, {{.css}}, and {{.properties}} files. The parse trees for AS consist of nodes from about 100 classes, such as {{LiteralNode}}, {{BinaryOperatorPlusNode}}, {{FunctionNode}}, and {{ClassNode}}. The parse trees for MXML consist of nodes from about 50 classes, such as {{MXMLDocumentNode}}, {{MXMLInstanceNode}}, {{MXMLScriptNode}}, etc. The ActionScript-y parts of MXML are represented by AS nodes that are children of MXML nodes. The symbol table consists of objects representing the things your code defines, such as {{ClassDefinition}}, {{FunctionDefinition}}, and {{VariableDefinition}}. These are stored in scope objects which form a hierarchy reflecting the lexical blocks of the source code. Falcon uses third-party grammars like JFlex, ANTLR, and JBurg to generate various lexers, parsers, and code generators. The lexers for AS and MXML are written in JFlex {{.lex}} files. The lexer for CSS, and the parsers for AS, MXML, and CSS, are written in ANTLR {{.g}} files. The code generator is written in JBurg {{.jbg}} files. JBurg is a Java implementation of a Bottom-Up Rewrite Generator (BURG) which generates Java code for a Bottom-Up-Rewrite Machine (BURM). The BURM uses patterns and rules to find subtrees within in an abstract syntax tree that it can "reduce" to an intermediate form, typically a sequence of bytecode instructions. The process continues until the entire tree is reduced to ABC, which goes into a {{DoABC}} tag of a SWF file. The typical data flow for an AS file is {noformat} .as file --> tokens --> abstract syntax tree --> file scope --> byte code and compilation problems {noformat} |
and
...
for
...
an
...
MXML
...
file
...
is
| No Format |
|---|
} .mxml file --> tokens --> XML DOM --> file scope --> abstract syntax tree -> byte code and compilation problems {noformat} |
To
...
maximize
...
performance,
...
MXML
...
is
...
compiled
...
directly
...
to
...
ABC,
...
not
...
to
...
ActionScript
...
source
...
code
...
or
...
an
...
ActionScript
...
parse
...
tree.
...
Falcon
...
tracks
...
where
...
in
...
the
...
source
...
every
...
token/node/definition
...
came
...
from,
...
to
...
support
...
operations
...
like
...
go-to-definition
...
in
...
Flash
...
Builder.
...
Falcon
...
has
...
the
...
general
...
concept
...
of
...
a
...
"problem",
...
where
...
a
...
problem
...
can
...
end
...
up
...
being
...
considered
...
an
...
error,
...
a
...
warning,
...
or
...
ignored.
...
Problems
...
are
...
discovered
...
by
...
the
...
semantic
...
checker,
...
which
...
is
...
part
...
of
...
the
...
same
...
phase
...
of
...
compilation
...
as
...
code
...
generation.
...
(This
...
minimizes
...
the
...
number
...
of
...
times
...
that
...
the
...
syntax
...
tree
...
must
...
be
...
traversed.)
...
Falcon
...
provides
...
live
...
problem
...
highlighting
...
to
...
Flash
...
Builder.
...
When
...
you
...
pause
...
during
...
editing
...
a
...
file,
...
the
...
file
...
is
...
compiled
...
and
...
the
...
problems
...
show
...
up
...
as
...
red
...
squiggly
...
underlines.
...
Falcon
...
tries
...
to
...
continue
...
after
...
almost
...
all
...
problems,
...
so
...
that
...
you
...
don't
...
necessarily
...
have
...
to
...
fix
...
every
...
problem
...
before
...
you
...
can
...
get
...
a
...
SWF
...
to
...
run.
...
Falcon
...
includes
...
libraries
...
for
...
reading
...
and
...
writing
...
SWFs
...
and
...
SWCs
...
files,
...
and
...
a
...
library
...
for
...
reading
...
and
...
writing
...
ActionScript
...
byte
...
code
...
(ABC),
...
at
...
the
...
level
...
of
...
individual
...
instructions.
...
Falcon
...
includes
...
transcoders
...
for
...
the
...
various
...
types
...
of
...
embedded
...
assets,
...
which
...
read,
...
for
...
example,
...
a
...
PNG
...
file
...
and
...
convert
...
it
...
to
...
the
...
form
...
required
...
inside
...
a
...
SWF.
...
It
...
does
...
NOT
...
support
...
font
...
trancoding,
...
because
...
this
...
relies
...
on
...
proprietary
...
Adobe
...
technology
...
which
...
Adobe
...
has
...
not
...
donated
...
to
...
Apache.
...
Instead,
...
you
...
must
...
use
...
a
...
separate
...
fontswf
...
tool
...
to
...
convert
...
your
...
font
...
files
...
to
...
SWF
...
files
...
and
...
then
...
embed
...
the
...
fonts
...
from
...
them.
...
FAQs
Please add questions here and people who contribute to Falcon will be happy to try to answer them.
Q: What is a code intelligence engine?
A: A library that supports smart editing in an IDE by offering code hinting, code completion, go-to-definition,
...
find-references,
...
refactoring,
...
live
...
error
...
highlighting,
...
etc.
...
These
...
things
...
are
...
useful
...
as
...
you
...
write
...
a
...
program,
...
even
...
if
...
you
...
don't
...
compile
...
and
...
run
...
it.
...
Q:
...
What
...
is
...
a
...
lexer?
...
A:
...
A
...
lexer
...
turns
...
a
...
source
...
code
...
file
...
into
...
a
...
linear
...
sequence
...
of
...
tokens.
...
For
...
example,
| No Format |
|---|
} trace(i + 1); {noformat} |
would
...
be
...
lexed
...
into
...
seven
...
token
...
objects,
...
represented
...
as
| No Format |
|---|
} TOKEN_IDENTIFIER "trace" TOKEN_LEFT_PAREN "(" TOKEN_IDENTIFIER "i" TOKEN_OPERATOR_PLUS "+" TOKEN_NUMERIC_LITERAL "1" TOKEN_RIGHT_PAREN ")" TOKEN_SEMICOLON ";" {noformat} _ |
Q:
...
What
...
is
...
a
...
parser?
...
A:
...
A
...
parser
...
turns
...
the
...
tokens
...
into
...
an
...
abstract
...
syntax
...
tree.
...
Q:
...
What
...
is
...
an
...
abstract
...
syntax
...
tree
...
(AST)?
...
A:
...
A
...
hierarchical
...
representation
...
of
...
the
...
source
...
code
...
as
...
a
...
tree
...
of
...
nodes
...
.
...
For
...
example,
...
the
...
function
...
call
| No Format |
|---|
} trace(i + 1); {noformat} |
is
...
represented
...
by
...
the
...
AST
| No Format |
|---|
} FunctionCallNode "trace" BinaryOperatorPlusNode IdentifierNode "i" LiteralNode 1 {noformat} |
where
...
indentation
...
indicates
...
a
...
parent-child
...
relationship.
...
Q:
...
What
...
is
...
a
...
definition?
...
A:
...
A
...
definition
...
is
...
something
...
that
...
can
...
be
...
referred
...
to
...
by
...
name.
...
This
...
includes
...
packages,
...
namespaces,
...
classs,
...
interfaces,
...
functions
...
(including
...
getters
...
and
...
setters),
...
parameters,
...
variables,
...
constants,
...
events,
...
styles,
...
and
...
effects.
...
Q:
...
What
...
is
...
a
...
scope?
...
A:
...
A
...
scope
...
corresponding
...
to
...
a
...
curly-brace
...
block
...
in
...
a
...
file
...
(or
...
an
...
entire
...
file)
...
and
...
contains
...
the
...
definitions
...
that
...
occur
...
there.
...
Each
...
definition
...
lives
...
in
...
a
...
particular
...
scope,
...
and
...
scopes
...
can
...
live
...
inside
...
other
...
scopes.
...
In
...
addition,
...
each
...
project
...
has
...
a
...
scope
...
which
...
contains
...
definitions
...
which
...
are
...
visible
...
outside
...
the
...
file
...
in
...
which
...
they
...
occur.
...
Q:
...
What
...
is
...
name
...
resolution?
...
A:
...
Name
...
resolution
...
determines
...
which
...
definition
...
an
...
identifier
...
refers
...
to
...
(or
...
"resolves
...
to",
...
or
...
"binds
...
to").
...
It's
...
what
...
the
...
F2
...
key
...
does
...
in
...
Flash
...
Builder.
...
For
...
example,
...
in
...
the
...
code
| No Format |
|---|
} private function f(s:String):void { var i:int = 1; g(s, i); } {noformat} |
the
...
identifier
...
s
...
that
...
is
...
the
...
first
...
argument
...
of
...
the
...
g
...
call
...
resolves
...
to
...
the
...
definition
...
of
...
the
...
parameter
...
named
...
s
...
while
...
the
...
identifier
...
i
...
that
...
is
...
the
...
second
...
argument
...
of
...
the
...
call
...
resolves
...
to
...
the
...
definition
...
of
...
the
...
local
...
variable
...
named
...
i
...
.
...
By
...
resolving
...
an
...
identifier
...
to
...
a
...
definition,
...
the
...
compiler
...
can
...
determine,
...
among
...
other
...
things,
...
the
...
type
...
of
...
the
...
identifier:
...
for
...
example,
...
s
...
is
...
a
...
String
...
,
...
and
...
it
...
can
...
then
...
check
...
whether
...
the
...
definition
...
of
...
the
...
g
...
function
...
accepts
...
a
...
String
...
as
...
its
...
first
...
argument.
...
Name
...
resolution
...
typically
...
involves
...
searching
...
up
...
the
...
scope
...
chain
...
for
...
a
...
definition
...
with
...
the
...
some
...
name.
...
Q:
...
What
...
is
...
a
...
code
...
generator?
...
A:
...
A
...
code
...
generator
...
turns
...
an
...
abstract
...
syntax
...
tree
...
into
...
bytecode.
...
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?
...
A:
...
A
...
semantic
...
checker
...
finds
...
problems
...
in
...
the
...
source
...
code.
...
Q:
...
What
...
is
...
an
...
example
...
of
...
how
...
Falcon
...
generates
...
better
...
bytecode
...
than
...
the
...
legacy
...
compiler?
...
A:
...
Falcon
...
does
...
constant
...
propagation
...
and
...
inlining.
...
Aditional
...
Information
...
about
...
Falcon
...
and
...
FalconJS
...
...
...
...
...
...