Skip to content
This repository has been archived by the owner on Jul 23, 2021. It is now read-only.
/ lily Public archive

Interpreted language focused on expressiveness and type safety.


Notifications You must be signed in to change notification settings


Repository files navigation

Pipeline Status Windows Build Coverage Report


Lily is a programming language focused on expressiveness and type safety.


scoped enum Color { Black, Blue, Cyan, Green, Magenta, Red, White, Yellow }

class Terminal(public var @foreground: Color, width_str: String)
    public var @width = width_str.parse_i().unwrap_or(80)

    public define set_fg(new_color: Color) {
        @foreground = new_color

var terms = [Terminal(Color.White, "A"), Terminal(Color.Red, "40")]

terms.each(|e| e.width += 20 )
     |> print



By default, Lily runs in standalone mode where all content is code to execute. But Lily can also be run in template mode. In template mode, code is between <?lily ... ?> tags. When a file is imported, it's always loaded in standalone mode, so that it doesn't accidentally send headers. Files that are imported are also namespaced (no 'global namespace').


Lily may be a statically-typed language, but the reference implementation is an interpreter. The interpreter as well as its API have been carefully designed with sandboxing in mind. As a result, it's possible to have multiple interpreters exist alongside each other.

Shorter edit cycle

Another benefit from having the reference implementation as an interpreter is a shorter turn around time. The interpreter's parser is comparable in speed to that of languages using an interpreter as their reference.


You need a C compiler and CMake (3.0.0 +). There are no external dependencies.

To build Lily, execute the following in a terminal:

cmake .


Note: Windows users may need to add -G"Unix Makefiles" to the end of the cmake invocation.

The above will build the lily executable, as well as a liblily that you can use with your program. It also builds pre-commit-tests.

Running tests

The centerpiece of Lily's testing is test_main.lily in the test directory. That file imports and invokes a large number of tests that cover a lot of Lily.

The make command also builds covlib and pre-commit-tests. No additional commands are necessary. covlib is a library that tests some parts of Lily that native code can't test. pre-commit-tests is a special runner that executes test_main.lily.

To run Lily's tests, execute pre-commit-tests from the directory it's in after building Lily.



The lily-garden repository contains a package manager (Garden) that simplifies the install of Lily packages.