oakfang/DemiLang

A basic attempt at a haskell-interpreted language

DemiLang

A basic attempt at a haskell-interpreted language

Building

git clone ...
cabal install
cabal build
alias demi=./dist/build/demi/demi.exe # used on windows GitBash

Usage

Usage:
demi.exe parse <filepath> -- print AST symbols (use for exec)
demi.exe (run) <filepath> -- parse and run the file on the fly
demi.exe exec <filepath>  -- run a pre-parsed AST symbols file
demi.exe                  -- run demi in stdin interpreter mode

Modules

You can import modules relative to the importing modules, like so:

// main.dm
import "foo.dm"; // this imports the file "foo.dm" from the same directory main.dm is

You can also install demiurges (Demi packages) using (urge)(https://github.com/oakfang/urge), running urge install <github_user>/<github_repo>.

Importing demiurges is done using this syntax (assuming the demiurge's name is Math, for example):

import Math;

Notice the lack of path and extension. This will import <running_directory>/urges/Math/main.dm.

Note: this time, the starting directory is the one you run demi from.

Creating Demiurges

A demiurge is a github repo containing at the very list 2 files:

• main.dm contains the file to be imported.
• urge.json is a JSON file containing at the very least a name property (in the above example, its value is "Math"), and maybe deps, which is a list of string in the format <github_user>/<github_repo>`. These dependencies will be installed along with your demiurge.

Done. Now anyone can install your demiurge!

Demo code

/*
Currently, stdlib contains:
print(ARG) => prints to stdout
read("int") => read an integer from stdin
read("bool") => read a boolean from stdin
read("str") => read a string from stdin
*/

greet = fn(name) {
    .print("Hello, " + name + "!");
};

opFn = fn(x, op, y) {
    if op == "+" return=x + y
    else if op == "-" return=x - y
    else if op == "*" return=x * y
    else if op == "/" return=x / y
    else {
        .print("Unsupported operator")
    }
};

.greet("world");

.print("Enter first number:");
a = read("int");

.print("Enter operator (+, -, *, /)");
op = read("str");

.print("Enter second number:");
b = read("int");
.print(opFn(a, op, b));