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Lavender is an interpreted, pure functional REPL-based programming language. It supports built in floating point numbers, strings, vectors, and maps, with lists and functional monads implemented in the standard libraries. Lavender is untyped, and it represents all values as functions. Lavender takes inspiration primarily from C, Python, and Scala.

This repository contains an implementation of Lavender in the C programming language. The original Java implementation is still around for posterity, but is no longer being updated.

Further documentation can be found on the Lavender GitHub pages site.

Running Lavender

After cloning the repository, you can run make to build the interpreter. Then, run the interpreter with ./lavender.

Example:

$ git clone https://github.com/kvverti/clavender.git
$ cd ./clavender
$ git submodule update --init
$ make
$ ./lavender

There are two options for make. The default mode release compiles with optimization and without debugging symbols, while debug mode compiles without optimization and with debug symbols and assertions intact. The makefile uses gcc for compilation. To compile without make, use the following command.

gcc -o lavender -DSTDLIB=\"<PROJECT_DIR>/stdlib/src\" src/*.c -lm

Lavender accepts the command line options -fp to set the filepath, -maxStackSize to set the maximum data stack size, and -debug to enable debugging output. Lavender runs in REPL mode by default, where you can enter expressions and see their results. By specifying a file to execute on the command line, Lavender instead executes the file and prints the result to stdout.

Installation instructions are also available on the documentation site.

Goals

The Lavender language is designed with the following restrictions to make things easier goals:

• Simplicity - Lavender has very few native constructs. Whenever some functionality can be implemented as a library function, it is.
• Immutability - Values in Lavender may never be modified; the concept of a variable does not exist. Constructs such as looping and iteration are expressed using recursion or generators.
• Referential transparency - Every terminating expression in Lavender has a well-defined value (even if the value is undefined), and this value does not change upon re-evaluation.
• Locality - Expressions are always evaluated in-order, nonlocal control mechanisms such as exceptions are not possible.
• Totality - Every value is a function, and every function is a value. Values can be meaningfully compared with one another.