Building Rascal from source - rascal

I'm thinking it might be easiest if I modify the Java syntax used in Rascal to better fit our Java-like language.
Is there a way I can build Rascal from the source? I've cloned the repo from Github and imported it as a project into Eclipse but there are some compilation errors regarding org.eclipse.imp. Before I head down the rabbit-hole of trying to get this all to work in Eclipse I thought I would post here to see if there is an easy way to handle this.
Thanks!

Sure you could build Rascal from scratch; following the developer instructions at https://github.com/cwi-swat/rascal/wiki/Rascal-Developers-Setup---Step-by-Step
On the other hand, if you wish to simply adapt the Java syntax definition it would be better to clone it into your own files. Grammars may look modular, but in reality there are complex interactions between different parts of the grammar. Better to clone and manage the whole thing as your own than depend on two co-evolving definitions.
If you clone the Java grammar Rascal will generate new parsers for you on-the-fly. If this generation becomes cumbersome, a "cached parser" can help you to optimize the deployment of your tools. Please contact us if you need help with that.

Related

Using large non-bazel dependencies in a bazel project

I would like to use a very large non-bazel system in a bazel project. Specifically, ROS2. This dependency provides a large number of python, C, and C++ libraries which are built using its own hand-rolled buildsystem. Obviously, I would like to avoid having to translate the entire buildsystem over to bazel.
Broadly, what's the best way of me doing this? In instinct was to use a custom repository rule to download the source (since it's split across many repositories), then use a genrule to call the ROS2 build system. Then write my simple cc_import and py_library rules for each of the individual components that I need.
However, I'm having trouble with the bit where I need to call the foreign build system. It seems that genrules require a list of output files to be specified, while I would like it to make an entire build directory available.
Before I spent any more time on this, I thought I'd ask whether I'm on the right lines since I'm new to bazel. Is this a good strategy? How would you approach this problem? Are there any other projects that mainly use bazel, but call other build systems in this way that I can look at?
As of recent, you can use rules_foreign_cc to call native CMake or make/configure like projects.

Autocomplete punctuation using grammar

I'm working on a tool that is able to autocomplete the necessary literals defined in a grammar. For example: in C# if a programmer enters: for with a space after it, then it's entirely possible to parse the code, determine that the programmer has started a for statement and autocomplete the necessary punctuation: ( ; ; ).
The more I think about the problem, the more I think there must already be a solution for it, because it's such a common use case, but I can't find anything.
Is there a tool that can do this using a given grammar?
If you don't mind using ANTLR v3 instead of v4 you can use Xtext in order to generate an editor that features auto-complete and error-highlighting. This will happen in form of a plugin for eclipse and apparently also for IntelliJ IDEA.
If you want to use a different IDE or simply want to make use of ANTLR v4's powerfull features you could still have a look at the Xtext Sources as they have to do what you are searching for in order to provide the above mentioned features properly...
This package looks very promising at first glance... You might find the respective code in there.
Be aware though that Xtext is mainly written with Xtend so you either have to do so as well or you have to rewrite it a bit

How to get type info from Go compiled packages in language x?

I want to write a simple editor with basic autocomplete functionality for the Go language as a pet project. How would one go about doing it? I took a look at the Go plugins for Eclipse and IntelliJ, but they were too big for me to comprehend (not to mention getting one to compile).
The Go standard library offers the building blocks for a Go parser which
you can use to parse the source files and look for function definitions and the like.
There's also the godoc command which
already does what you want: extracting method definitions and it's documentation. You may look in the
source code to see how godoc is
working or use godoc directly.
This editor written in Go projects has a manageable amount of code,
you may look into it.
The de facto standard approach to this problem is to use nsf's gocode. I have tried it only in Vim - it works very well.
Even though there's ready made support for specific editors, gocode is not editor specific. It's a daemon with a communication protocol. It is thus usable from any program.

Any tools for clojure to parse java source code? [duplicate]

I'm trying to analyze Java source files with Clojure but I couldn't find a way to do that.
First, I thought using Eclipse AST plugin(by copying necessary JAR's to my Clojure project) but I gave up after seeing Eclipse AST's API(visitor based walker).
Then I've tried creating a Java parser with ANTLR. I can only find one Java 1.6 grammar for ANTLR( http://openjdk.java.net/projects/compiler-grammar/antlrworks/Java.g ) and it doesn't compile with latest ANTLR(here's the errors I'm getting ).
Now I have no idea how can I do that. At worst I'll try to go with Eclipse AST.
Does anyone know a better way to parse Java files with Clojure?
Thanks.
Edit: To clarify my point:
I need to find some specific method calls in Java projects and inspect it's parameters(we have multiple definitions of the method, with different type of parameters). Right now I have a simple solution written in Java(Eclipse AST) but I want to use Clojure in this project as much as possible.
... and it doesn't compile with latest ANTLR ...
I could not reproduce that.
Using ANTLR v3.2, I got some warnings, but no errors. Using both ANTLR v3.3 and v3.4 (latest version), I have no problems generating a parser.
You didn't mention how you're (trying) to generate a lexer/parser, but here's how it works for me:
java -cp antlr-3.4.jar org.antlr.Tool Java.g
EDIT 1
Here's my output when running the commands:
ls
wget http://www.antlr.org/download/antlr-3.4-complete.jar
wget http://openjdk.java.net/projects/compiler-grammar/antlrworks/Java.g
java -cp antlr-3.4-complete.jar org.antlr.Tool Java.g
ls
As you can see, the .java files of the lexer and parser are properly created.
EDIT 2
Instead of generating a parser yourself (from a grammar), you could use an existing parser like this one (Java 1.5 only AFAIK) and call it from your Clojure code.
It depends a bit on what you want to do - what are you hoping to get from the analysis?
If you want to actually compile Java or at least build an AST, then you probably need to go the ANTLR or Eclipse AST route. Java isn't that bad of a language to parse, but you still probably don't want to be reinventing too many wheels..... so you might as well build on the Eclipse and OpenJDK work.
If however you are just interesting in parsing the basic syntax and analysing certain features, it might be easier to use a simpler general purpose parser combinator library. Options to explore:
fnparse (Clojure, not sure how well maintained)
jparsec (Java, but can probably be used quite easily from Clojure)

How can I build PDF LaTeX documents with ANT (or some other build system if you prefer)?

The team I work for manages a large collection of technical documentation which is written in LaTeX.
Currently all the documentation we have is manually built by the editors and then checked into a version control system. Sometimes people forget to compile their documents so we have a situation where the PDF and .tex files are often out of step. Unfortunately when this happens our users find themselves reading old versions of our document.
I've managed to hack a simple script to build PDFs using Make - it's rather clumsy.
I was wondering if there was a better way to do it? Most people in our department use Eclipse + Pydev for a Python project which means we are all very familiar with this IDE. I know that Ant plays nicely with Eclipse, so might we be able to use this tool for our doc building?
So what's the best way of doing this? I hope I will not have to learn everything there is to know about a new build-system in order to automate the building of some quite simple docs.
There is an external Ant task for LaTeX PDF generation, though the site is in German.
To use it, download the jar to a location on your machine, then define a taskdef as follows:
<taskdef name="latex" classname="de.dokutransdata.antlatex.LaTeX"
classpath="/path/to/ant/lib/ant_latex.jar"/>
Then to use it, define a target like this:
<target name="doLaTeX">
<latex
latexfile="${ltx2.file}"
verbose="on"
clean="on"
pdftex="off"
workingDir="${basedir}"
/>
</target>
Where ltx2.file is the file to process.
This is a link to the howto page listing the parameters. If you need any more options, my German is just about passable enough to explain, maybe.
There is also a maven plugin for LaTeX, but I can't find any documentation.
Haven't tried it, but I remember seeing a blog post about it.
If you know python, this blog post might be interesting
EDIT: Also, I would assume that you're using some kind of version control system, and I can't say for sure, but I use git to manage all my latex docs, and it might be possible to use some kind of post-commit hook to execute a script to rebuild the document. This would depend on how your repository is structured... just thinking out loud, so to speak.
I went into great detail on a large number of build systems for latex in this question, but its slightly different in your case. I think you want rubber or latexmk. The latex-makefile seems a good idea, but only supports building via postscript, which might not be your build process.
In general, its a good idea to keep generated files outside of version control for just this reason. A good exception is when specialist build tools are not widely available, and your situation sounds similar. You might do better with a commit-hook to build automatically upon commit.
I guess I should also point out that committing something without first building it and checking it is a deadly sin, so a better solution might be to stamp that out.
Maven is a better alternative as build system compared to Ant. So I would recommend a maven-plugin to generate PDF from LaTeX sources. Have a look at mathan-latex-maven-plugin

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