It doesn't require a rewrite, but a rewrite could simplify integrating a
usecase like this as well as integrating other features that we already
have into it and making them simpler and unified inthe code. I agree the
usecase is an excellent one which could simplify the lives of exactly
the type of users I am talking about.
It sounds like you are suggesting that the dependency tree be extensible
and modifiable, perhaps manipulable, within targets as well so long as
that part of the tree hasn't run yet. In a sense that is what macros do
because they allow you to swap in some static block of tasks to replace
a single task. There is also the feature from EasyAnt for changing
target dependencies. But what I'm hearing is that you want more
flexibility than that.
Something to walk the existing dependency tree, perhaps, with
conditional behaviors to modify the metadata on existing element such as
dependencies and if/unless, replacing the element with another or a
subtree (perhaps itself dynamically walked and created), adding
branches, perhaps deleting elements or subtrees. Kind of like what we
can do with a tree of files and directories already. Does that sound
like what the design you'd like to see would have?
And perhaps it could encompass providing both the macro and target
dependency changes to the tree as well, along with any other code we
have that alters the dependency tree. I'm not sure which of the various
ways to call back into Ant do this. I'm sure there are other examples in
the codebase.
I'm not familiar enough with this part of the code any more to know
whether there is already a single elegant solution in Ant 1 that all the
code which modifies the dependency tree shares, but given our BC
requirements I doubt it.
One example of a FileSystemProvider that Java 7 suggests in its API docs
is a "memory" file system, one identified by the URL "memory://".
Perhaps our dependency tree could be a kind of file system, then we
could reuse vast swathes of code we already have, both in the standard
class libraries and in Ant itself. Just an idea off the top of my head.
On 2/17/2012 5:53 AM, Dominique Devienne wrote:
2012/2/17 Bruce Atherton<br...@callenish.com>:
A lot of companies have their own, internally written build file generators
just so their build systems are consistent and exactly what they want. Our
Related Projects and External Tools page has some of these that were made
public, I suspect.
Surely there is a better way than requiring users of Ant to write generators
to deal with the complexity and keep it customized.
At one point I did write a build(s) (XSLT-based) generator
specifically for a large and hairy project. Later I rewrote the whole
thing with macrodefs. But my point is that I don't view build
generators as bad, in fact it often helps IMHO to have a declarative
custom DSL (in XML in my case, so read "DSL" with a grain of salt)
that's used as the input for generating Ant build fragments, and have
those fragments be able to "insert" them into the target graph. I've
also long felt Ant needed generalized if/unless/os (and my own
extensions like ifTrue, unlessTrue, when) on any "XML tag" (or
UnknownElement if you prefer), just read the recent "add if/unless to
<javac>'s<compilerarg>" thread.<macrodef> is nice, but you can't use
it for arbitrary, *and conditional*, XML "fragments" inside tasks. All
those things you can often do more easily with a generator, but that's
often cumbersome, doesn't play well with IDEs, etc... I guess I'm
saying I've often wished for generator-like features as a built-in
part of Ant. Do you see what I'm saying? Ant now does late
"conversion" from UnkownElement to actual configuration of the Java
code it maps to, and a way to influence/transform that almost AST-like
graph would make Ant more powerful and flexible, perhaps at the
expense of creating "dialects" unreadable to someone not familiar with
them. Given Ant's XML roots, perhaps a tighter built-in integration
with XSLT to dynamically "rewrite" the build at runtime/buildtime
would be one way to achieve what I envision (notwithstanding the talks
of non-XML front-ends of course).
Stepping of my soapbox now :) What I'm saying has nothing to do with
Java7, nor necessarily require a rewrite either. --DD
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