Installing ANTLR4 in your Linux

Java

Make sure you have Java installed. Check it with

java -version

If you don’t have it, install it normally with your distro package manager.

ANTLR4

Option 1: Using the package manager

Modern Linux distros already include a package for ANTLR, although it is probably too old.

sudo apt-get install antlr4

Option 2: Getting the jar file

Alternatively, you can go to https://www.antlr.org and follow the instructions there, which mainly consist of:

# Download antlr4 jar file to /usr/local/lib
cd /usr/local/lib
sudo wget http://www.antlr.org/download/antlr-4.13.2-complete.jar

IMPORTANT: Do NOT use earlier versions than 4.13, the API is different and it will not work with our code.

You will also need to create a command file that will ease the call to Antlr4. Edit a file named antlr4 and write into it:

#! /bin/bash
export CLASSPATH=".:/usr/local/lib/antlr-4.13.2-complete.jar:$CLASSPATH"
java -jar /usr/local/lib/antlr-4.13.2-complete.jar "$@"

save the file, and give it execution permission:

chmod +x antlr4

finally, move it to a folder in the default PATH

sudo mv antlr4 /usr/local/bin

C++ Runtime

Although Antlr4 is a Java-universe project, it can be instructed to generate C++ code. The resulting code uses some C++ classes included in a shared library (the runtime) that is not installed by default with Antlr4. To install it we can follow the steps below:

Option 1: Using the package manager

Some linux distributions have this library packaged. Installing the dev package should pull the binaries too. Make sure the version matches the 4.13 ANTLR version installed.

sudo apt-get install libantlr4-runtime-dev

Option 2: Compiling from source

If your distribution does not provide this package, you’ll need to install it from source:

First, install required tools and dependencies:

sudo apt-get install cmake uuid-dev pkgconf

Then, download the source from https://www.antlr.org/download.html and compile it.

# download source
mkdir antlr-src && cd antlr-src
wget http://www.antlr.org/download/antlr4-cpp-runtime-4.13.2-source.zip
# unzip file
unzip antlr4-cpp-runtime-4.13.2-source.zip
# create build directory for cmake
mkdir build && cd build
# create makefiles
cmake .. -DANTLR_JAR_LOCATION=/usr/local/lib/antlr-4.13.2-complete.jar -DCMAKE_INSTALL_PREFIX=/usr/local -DWITH_DEMO=True
# build and install
make
sudo make install

If you installed Antlr4 from a distribution package, your ANTLR_JAR_LOCATION will be something like /usr/share/java/antlr4-4.13.2.jar. Examine the contents of the package and set the right path in the cmake command.

Adapting Makefiles

Makefiles provided with the class exercises and lab project expect Antlr4 runtime to be in /assig/$USER/cl/runtime

In order to run them in your computer, you need to edit the Makefile and replace line 80

ANTLR_ROOT := /assig/$(USER)/cl/runtime

with

• If you installed from distribution packages:

  ANTLR_ROOT := /usr
  

• If you installed the jarfile directly, set it to the folder where you created the antlr4 command file

  ANTLR_ROOT := /usr/local
  

Once the Makefile is fixed, you should be able to compile the class examples:

cd intro/lab1/Calc
make antlr
make
./main calc1.txt

Setting up Library Paths

If you get errors when running your ./main program, it may be that the loader is not finding the runtime.

If you installed the runtime in /usr/local/lib you may need to update loader paths:

sudo ldconfig

If you installed the runtime in some other folder, you need to set the right environment variables so that the loader finds it:

export LD_LIBRARY_PATH=/my/runtime/folder

You can add this line to your .bashrc to avoid having to do it for every session.

MacOS users: in MacOS the variable name is DYLD_LIBRARY_PATH

Using grun to visualize trees

You can use grun to visualize and debug the trees your grammar is creating.

Details on how to do so are given in the Introduction to ANTLR4 page.

However, to run it in your computer you’ll need to set up the paths for the java components of ANTLR4. Edit your $HOME/.bashrc file and add the commands:

export ANTLR4=/usr/share/java
if ( $?CLASSPATH ) then
    export CLASSPATH=.:$ANTLR4/antlr-4.13.2-complete.jar:$CLASSPATH
else
    export CLASSPATH=.:$ANTLR4/antlr-4.13.2-complete.jar
fi

If you installed antlr4 by getting the jarfile instead of using the package manager, you may need to change the path /usr/share/java to another location (e.g. /usr/local/share/java or wherever you installed it)

Once .bashrc has been updated, open a new terminal to get the new configuration loaded.