veggero / nylo

Nylo's programming language interpreter.

Nylo is a declarative programming language. It takes some constructs from functional and logic paradigms, but it’s really a new paradigm itself. It aims to be simple and clear, but powerful. It provides an easy way to make assertions on the data a function is working on. It also gives you the possibility to define standard behaviour if asserts fail.

fib: (
    n: int
    prevs: fib(n: n-1) + fib(n: n-2)
    result: if(cond: n<2, then: n, else: sum_prev_fibs)
    -> result
)

Contents

• Present and future of project
• Markup / Configuration file
  1. Structures
  2. Lists
  3. Multiple words
  4. Other kind of variables
• Programming Language
  1. It’s simple and orthogonal
  2. It’s explicit and clear
  3. Curried function and classes
  4. Inverse function and classes

Present and future of project

This repo contains the development version of the proof-of-concept of the programming language. The poc should be finished on the 25th of May, but due to complications in the type and overloading systems, it might slip further.

As soon as the proof-of-concept is finished and refined, the work on the actual interpreter will start. It will be written in Go/Rust/Ida.

Markup / Configuration file

Nylo aims to be clear enough to be used to markup or configuration files. An example can be found on http://niccolo.venerandi.com .

Structures

grades: (
    first_semester: (
        math: 7
        science: 9
        language: 6
    )
    second_semester: (
        math: 8
        science: 8
        language: 7
    )
)

Lists

numbers: (
    high: (
        4201337,
        3290941,
        4129301
    )
    low: (1, 2, 3)
)

Multiple words

first level: (
    enemy life: 100
    enemy power: 50
)
second level: (
    enemy life: 150
    enemy power: 80
)

Other kind of variables

Any variable can be used by putting ` before and after the name.

symbols: (
    `+`: "plus"
    `-`: "minus"
)
years: (
    `2017`: "kinda cool"
    `2018`: "please let's go back"
)
other weird names: (
    `(!WOW!)`: "WOW!"
    `--> :0 <--`: "WOW!"
)

Programming Language

It’s simple and orthogonal

Nylo has very few constructs. In fact, everything is a structure, which is put in the form of (a: b, c: d -> e)

// Class
point: (
    x: int
    y: int
)

// Function
double: (
    n: int
    r: n * 2
    -> r
)

// Call
twenty: double (
    n: 10
    -> r
)

// Namespace
smallnumbers: (
    zero: 0
    one: 1
    two: 2
)

// Enum
traffic_lights: (
     green: ()
     yellow: ()
     red: ()
)

// List
languages: (
    "Python"
    "Go"
    "C"
)

It’s explicit and clear

Nylo makes everything explicit, even function calls!

screen.drawings: (
    rectangle(
        position: point(x: 5, y: 15)
        size: point(x: 10, y: 10)
        color: (red: 255, green: 0, blue: 0)
    )
)

The same thing with pygame is:

pygame.draw.rect(
    screen,
    (255, 0, 0),
    (5, 15, 10, 10)
)

As you can see, Nylo is easier to understand.

Curried function and classes

Not all arguments has to be passed in the first call. You can use -> to curry.

add: (
    a: int
    b: int
    -> a + b
)

add(a: 1, b: 2) = 3

add_three: add(a: 3 ->)
add_three(b: 5) = 8

Also, not all class proprieties has to be passed in the first call.

point: (
    x: int
    y: int
)

A: point(x: 5, y: 10)

x_axis: point(y: 0 ->)
y_axis: point(x: 0 ->)

B: x_axis(x: 5)
C: y_axis(y: 10)

Inverse function and classes

You can make function that also works backward:

double: (
    n: result / 2
    result: n * 2
    -> result
)

double(n: 10) = 20
double(n: 10 -> result) = 20
double(result: 20 -> n) = 10

And you can also have multiple ways to define classes:

color: (
    r: hex[1:3].base_10
    g: hex[3:5].base_10
    b: hex[5:7].base_10

    hex: '#' & r.base_16 & g.base_16 & b.base_16
)

color(r: 255 g: 0 b: 0)
color(hex: "#ff0000")

color(r: 0 g: 122 b: 54 -> hex)
color(hex: "#c8ec8e" -> r)

No one own this, you can do whatever you want with this code, and you should not care about who made it. Have fun!