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##DESCRIPTION Cling is an interactive C++ interpreter, built on top of Clang and LLVM compiler infrastructure. Cling realizes the read-eval-print loop (REPL) concept, in order to leverage rapid application development. Implemented as a small extension to LLVM and Clang, the interpreter reuses their strengths such as the praised concise and expressive compiler diagnostics.

Further information & demos

Please note that some of the resources are rather old and most of the stated limitations are outdated.

• https://github.com/root-mirror/cling/tree/master/www/docs/talks
• http://blog.coldflake.com/posts/2012-08-09-On-the-fly-C++.html
• http://solarianprogrammer.com/2012/08/14/cling-cpp-11-interpreter/
• https://www.youtube.com/watch?v=f9Xfh8pv3Fs
• https://www.youtube.com/watch?v=BrjV1ZgYbbA
• https://www.youtube.com/watch?v=wZZdDhf2wDw
• https://www.youtube.com/watch?v=eoIuqLNvzFs

##INSTALLATION ###Binaries We offer binary snapshots for download at https://root.cern.ch/download/cling/

###Source CLING source depends on the LLVM and CLANG headers and libraries. You will also need CMake >= 2.6.1 or GNU Make to build all of those packages and subversion and git to get the source code.

####Building Building LLVM and CLANG you must:

• Check out the sources:

    git clone http://root.cern.ch/git/llvm.git src
    cd src
    git checkout cling-patches
    cd tools
    git clone http://root.cern.ch/git/cling.git
    git clone http://root.cern.ch/git/clang.git
    cd clang
    git checkout cling-patches

• Configure, build and install them, either using CMake:

    cd ../../../
    mkdir build
    cd build
    cmake -DCMAKE_INSTALL_PREFIX=/some/install/dir \
          -DLLVM_TARGETS_TO_BUILD=host \
          -DCMAKE_BUILD_TYPE=Debug \
          ../src
    make
    make install

• or GNU Make (see ../src/configure --help for all options):

    cd ../../../
    mkdir build
    cd build
    ../src/configure --prefix=/some/install/dir
    make
    make install

#####Cling Packaging Tool Cling's tree has a user-friendly, command-line utility written in Python called Cling Packaging Tool (CPT) which can build Cling from source and generate installer bundles for a wide range of platforms.

If you have Cling's source cloned locally, you can find the tool in tools/packaging directory. Alternatively, you can download the script manually, or by using wget:

wget https://raw.githubusercontent.com/root-mirror/cling/master/tools/packaging/cpt.py
chmod +x cpt.py

Full documentation of CPT can be found in tools/packaging.

##USAGE /some/install/dir/bin/cling '#include <stdio.h>' 'printf("Hello World!\n")' To get started run: /some/install/dir/bin/cling --help or type /some/install/dir/bin/cling [cling]$ .help

Jupyter

cling comes with a Jupyter kernel. After building cling, install Jupyter and run jupyter kernelspec install cling. It requires a fairly new Jupyter. Make sure cling is in your PATH when you start jupyter!

##DEVELOPERS' CORNER We have doxygen documentation of cling's code at: http://cling.web.cern.ch/cling/doxygen/

###CONTRIBUTIONS Every contribution is very welcome. It is considered as a donation and its copyright and any other related rights become exclusive ownership of the person who merged the code or in any other case the main developers. In order for a contribution to be accepted it has to obey the previously established rules for contribution acceptance in cling's work flow and rules.