Is there an ANTLR4 Ant task? - ant

I haven't been able find an Ant task that works out of the box with ANTLR4. I want to be able to invoke options like -visitor to generate the *Visitor interfaces and classes. I suppose I could 'fake it' using the Java task.

You shouldn't need one. Take a look at the build script I use for the grammars in ANTLRWorks 2.
Downloads the correct version of the tool on-demand (so it doesn't have to be included in source control).
Only rebuilds grammars if they are out-of-date.
Builds grammars in parallel for improved build times.
https://github.com/sharwell/antlrworks2/blob/master/org-antlr-works-editor/build.xml

Related

Are the bazel buildtools primarily focused on single starlark files?

I'm taking a glance over at the buildtools repo (https://github.com/bazelbuild/buildtools) and trying to understand the scope of its responsibilities as it relates to the three phases of a bazel build (loading, analysis, execution)
The repo's description states that it is A bazel BUILD file formatter and editor. I find much logic in the repo written in go-lang that lends complete support for an AST parser, starlark syntax interpreting capabilities, reformatting and rewriting of BUILD files and what not. Basically there's logic designed to operate upon a single starlark file at a time. Rereading that repo description in this light leads me to conclude that buildtools is really a single file scoped effort and presents tools that only intersect functionality wise (perhaps only partially) to those loading operations bazel conducts while building.
Question: Is it accurate that the focus of buildtools is upon the single starlark file?
If that's true then all the multiple starlark file analysis logic and so forth seems to actually be maintained over at https://github.com/bazelbuild/bazel/tree/master/src/main/java/com/google/devtools/build/lib and I should not expect to find any tools for the analysis phase and beyond in the buildtools repo. Is that right?
I don't work on Buildtools, but we agree: these tools seem to focus on BUILD / .bzl files in isolation. They let you process these files in parallel, to do similar operations on them.
If you wonder whether these tools understand relations between these files, the answer seems to be no.
If you further wonder what tools do then, the answer is Bazel's query, cquery, and aquery. I'm not aware of a programmable API for these queries though; you have to run Bazel to perform them.
buildtools has tools working on a syntactic level (it looks at the syntax tree). These tools are outside of Bazel and have no knowledge of Bazel build phases. In the future, we may expand the code to work on multiple files (for the static analysis), but it will still be independent from Bazel phases.
https://github.com/bazelbuild/bazel/tree/master/src/main/java/com/google/devtools/build/lib/ is the source code of Bazel. The syntax/ directory includes the code for reading and evaluating the Starlark files. The code there is called by Skyframe. The interpreter is called by Skyframe many times in parallel, both during the loading and the analysis phases.
If you have a more specific question (what are you trying to do?), I can help more. :)

ant ask user which target to call if not specified

i have this ant build.xml file with 3 targets in it:
target1, target2 and target3.
If the user simply runs ant and not an explicit ant target1 or something like that, i want to prompt the user asking which target he would like to call.
Remember, the user should only be prompted for this only if he doesnt explicitly call a target while running ant
Ant is not a programming language, it's a dependency matrix language. There's a big difference between the two.
In a program language, you can specify the absolute order of sequence. Plus, you have a lot more flexibility in doing things. In Ant, you don't specify the execution order. You specify various short how to build this steps and then specify their dependencies. Ant automatically will figure out the execution order needed.
It's one of the hardest things for developers to learn about Ant. I've seen too many times when developers try to force execution order and end up executing the same set of targets dozens of times over and over. I recently had a build her that took almost 10 minutes to build, and I rewrote the build.xml to produce the same build in under 2 minutes.
You could use <input/> to get the user input, then use <exec> or <java> to execute another Ant process to execute the requested target. However, this breaks the way Ant is suppose to work.
The default target should be the default target that developers would want to execute on a regular basis while they program. It should not clean the build. It should not run 10 minutes of testing. It should compile any changed files, and rebuild the war or jar. That's what I want about 99% of the time. The whole process takes 10 seconds.
I get really, really pissed when someone doesn't understand this. I hate it when I type ant and I get directions on how to execute my build. I get really irritated when the default target cleans out my previous compiles. And, I get filled with the deadly desire to pummel the person who wrote the damn build file with a large blunt object if I am prompted for something. That's because I will run Ant, do something else while the build happens, then come back to that command window when I think the build is done. Nothing makes me angrier to come back to a build only to find out it's sitting there waiting for me to tell it which target.
If you really, really need to do this. Use a shell script called build.sh. Don't futz with the build.xmlto do this because that affects development.
What you really need to do is teach everyone how to use Ant:
Ant will list user executable targets when you type in ant -p. This will list all targets, and their descriptions. If a target doesn't have a description, it won't list it. This is great for internal targets that a user shouldn't execute on their own. (For example, a target that merely does some sort of test to see if another target should execute). To make this work, make sure your targets have descriptions. I get angry when the person who wrote the Ant file puts a description for some minor target that I don't want, but forgets the description of the target I do want (like compile). Don't make David angry. You don't want to make David angry.
Use default target names for your group. That way, I know what targets do what across the entire project instead of one project using BUILD vs. build-programs vs. Compile vs build-my-stuff vs. StuffBuild. We standardized on Maven lifecycle names names. They're documented and there's no arguments or debates.
Do not use <ant/> or <antcall> to enforce build order. Do not divide your build.xml into a dozen separate build.xml programs. All of these probably break Ant's ability to build a target dependency matrix. Besides, many Ant tools that show dependency hierarchy in a build and they can't work across multiple build files.
Do not wrap your builds inside a shell script. If you do this, you're probably not understanding how builds work.
The build should not update any files in my working directory that were checked out by me. It shouldn't polute my working directory with all sorts of build artifacts spread out all over the place. It shouldn't do anything outside of the working directory (except maybe do some sort of deploy, but only when I run the deploy target). In fact, all build processing should take place in a sub-directory INSIDE my working directory. A clean should merely delete this one directory. Sometimes, this is called build, sometimes dist. I usually call it target because I've adopted Maven naming conventions.
Your build script should be a build script. It shouldn't do checkouts or updates -- at least not automatically. I know that if you use CruiseControl as a continuous build process, you have to have update and checkout functionality inside your build.xml. It's one of the reasons I now use Jenkins.
Sorry about this answer not necessarily being the one you're looking for. You didn't really state what you're doing with Ant. If you're doing builds, don't do what you're trying to do. If you're writing some sort of program, use a real programming language and not Ant.
An Ant build should typically finish in under a minute or two, and redoing a build because you changed a file shouldn't take more than 30 seconds. This is important to understand because I want to encourage my developers to build with Ant, and to use the same targets that my Jenkins server uses. That way, they can test out their build the same way my Jenkins server will do the official build.
you may use the input task provided by ant and make it your default target.
<input
message="Please enter Target ID (1,2 or 3):"
validargs="1,2,3"
addproperty="targetID"
/>
Use the value of this property to decide which target to execute.
From the ant documentation:
message : The Message which gets displayed to the user during the build run.
validargs: Comma separated String containing valid input arguments. If set, input task will reject any input not defined here.
You may pass any arguments according to your needs.
addproperty : The name of a property to be created from input.Behaviour is equal to property task which means that existing
properties cannot be overridden.

Run JUnit tests in parallel

When running unit tests, Gradle can execute multiple tests in parallel without any changes to the tests themselves (i.e. special annotations, test runners, etc.). I'd like to achieve the same thing with ant, but I'm not sure how.
I've seen this question but none of the answers really appeal to me. They either involve hacks with ant-contrib, special runners set up with the #RunWith annotation, some other special annotations, etc. I'm also aware of TestNG, but I can't make the Eclipse plug-in migrate our tests - and we have around 10,000 of them so I'm not doing it by hand!
Gradle doesn't need any of this stuff, so how do I do it in ant? I guess Gradle uses a special runner, but if so, it's set up as part of the JUnit setup, and not mentioned on every single test. If that's the case, then that's fine. I just don't really want to go and modify c. 10,000 unit tests!
Gradle doesn't use a special JUnit runner in the strict sense of the word. It "simply" has a sophisticated test task that knows how to spin up multiple JVMs, run a subset of test classes in each of them (by invoking JUnit), and report back the results to the JVM that executes the build. There the results get aggregated to make it look like a single-JVM, single-threaded test execution. This even works for builds that define their own test listeners.
To get parallel test execution in Ant, you would need an Ant task that supports this feature (not sure if one exists). An alternative is to import your Ant build into Gradle (ant.importBuild "build.xml") and add a test task on the Gradle side.

Generic ant rules script as an alternative to using Maven

Android has an ant script file with generic targets for compile, clean, etc.
Are there any open source ant scripts that define standard targets such as these for general java projects?
I don't want to bother installing and using maven, but I also don't want to bother creating and maintaining ant scripts for each project.
I'm guessing you are new to both Maven and Ant. If I'm wrong you can ignore the rest of this post :)
I don't know of any generic open source Ant files. I've never had the need to look for one. I think its well worth the effort to learn Ant and create your own generic script. Ant is easy to learn and it is a very flexible, powerful and reliable build tool. You'll find it quite easy to create a build file that you can reuse over and over again on different projects.
With regards to having to maintain Ant scripts, its a bit of a fallacy. You'll find that once you've got a script that works in a generic way you'll hardly ever have to touch it again except when you need to do things in a custom way (usually around packaging and deployment). When that happens, you'll be glad you're using a tool like Ant that gives you the flexibility to do what you want to be able to do without getting in your way.

Hudson on Windows: what is better - Ant files or Batch files?

I have some hudson servers for our CI process.
The build tasks use Ant scripts and also old-school *.bat files.
What do you prefer? What are the pros and cons?
(I think of readability, familiarity to developers and extensibility...)
Are there any other options? We have .Net, Java and PHP apps to test.
Batch is a programming language (and not a very good one at that). Ant is a dependency matrix language. What's the difference?
In a programming language, you specify the order everything occurs in. You're responsible to say what is built and the order.
In a dependency matrix language, you merely state the dependencies, and the program figures out what to do and the order it should be done in. One of the biggest issues developers have with Ant or Make is to try to force a build order instead of letting the build system take care of it.
Builds should always be done with a dependency matrix language like Ant.
Let Ant determine what needs to be built and the order it should be built. Don't use Batch. If you're using Batch scripts to call a bunch of Ant script in the order you think they should be called, you're doing it wrong. Have a master Ant script do it and use <subant> calls. Let Ant do the tricky stuff.
You can use batch script to do preliminary work (such as setting ANT_OPTS if Ant needs more memory, or setting environment variables like ANT_HOME and JAVA_HOME and your %PATH% variable to make sure you're using the correct Java and Ant versions. In Hudson, you can set all of this in the Hudson job itself, so you don't have to call the Batch script.
*.bat files pretty much restrict you to dos/windows, like how shell scripts are for linux, whereas Ant/Maven is cross-platform and gives you the option to use a non-Windows CI server

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