The Egel Language

Egel is an untyped concurrent functional scripting language based on eager combinator rewriting with a concise but remarkably powerful syntax.

Installation

This interpreter is being developed on Linux/MacOS/BSD and uses libicu for Unicode support and fmt for formatting.

You need to have the GNU or LLVM compiler chain for C++17, the development files for libicu (65.0) and fmt (8.0), and cmake (3.13) installed. Most package managers will provide that for you.

This interpreter is made with cmake in the standard manner. Run the following commands on a Linux system.

    mkdir build
    cd build
    cmake ..
    make

note: on MacOS you need to provide the location of what you want to link against. Since most people will be using brew, use this

    cmake .. -DCMAKE_PREFIX_PATH=/opt/homebrew/opt/icu4c

note: for older GCC you sometimes need to uncomment the stdc++fs rule.

That should give you an interpreter named egel and a number of dynamically loadable Egel object files in the build directory.

For a system-wide install run make install after a build as root.

On some systems the EGEL_PATH environment variable needs to be set. See the man page for further information on that.

If you don't want to do that, please note that you only need the interpreter named egel and the prelude in the include directory for simple tasks.

Cmake generated makefiles allow for a local install with the command:

    make DESTDIR=~ install

In this case Egel components will be installed into ~/usr/local directories and you might refer to those components by adding the following commands to your shell resource file, though the specific syntax may differ.

    export PATH=~/usr/local/bin:$PATH
    export EGEL_PATH=~/usr/local/lib/egel

Usage

There's a manual page you can consult, it should be installed, or read the following short introduction to the interpreter on the internet.

For a list of builtin combinators look here.

Also

The interpreter doesn't provide command line editing, you might want to wrap it with the command alias egel="rlwrap egel".

The interpreter allocates lots of short-lived objects. If you want a bit of extra speed, it might pay off to switch the allocator.

I use jemalloc on Linux by setting LD_PRELOAD=`jemalloc-config --libdir`/libjemalloc.so.`jemalloc-config --revision.