DreamBerd rs

Rust-based interpreter for the DreamBerd language.

The full specification for DreamBerd is available at https://github.com/TodePond/DreamBerd. This file only contains the segments of the specification that are implemented in DreamBerd-rs, along with some of my own additions.

Rapidly-Evaporating Program Logic (REPL)

DreamBerd provides a convenient mode to execute code within the terminal. The preservation of state allows you to play with features of DreamBerd without writing your code into a file. You can also include code from a file by providing the filename as an argument, which will run it and allow you to play around in what remains.

Statements

Every statement ends with an exclamation mark! If you're feeling extra, you can even use multiple!!!

print "Hello World!"!

print "Hi!!"!!!!

If you're unsure, that's okay too! You can also use question marks? This will print debug information to the console? The more question marks, the more detailed the information???

print "uh... hi??"???

Negation

You might be wondering what DreamBerd uses for its negation operator, since most languages use !. Don't worry! ; can negate the value in front of it.

;"hello there"? // "ereht olleh"
;true? // false
;1 // -1

Declarations

There are four types of declarations. Constant constants can't be changed at all.

const const name = "Ava"!
name += "?"! // does nothing
name = "John"! // does nothing

Constant variables can be edited but not reassigned.

const var age = 1!
age += 1!
age? // 2

Variable constants can be reassigned but not edited.

var const id = "main"!
id = "no thank you"!
id? // "no thank you"

Variable variables can be reassigned and edited.

var var count = 0!
count += 1!
count = 2!

Types

DreamBerd is a weakly-typed language. However, type annotations can be added to declarations and functions.

var const name: String = "Gary"!
const var age: i32 = 22!

const const mul: Fn<i32, i32> = (lhs: i32, rhs: i32)->{
    lhs * rhs
}!

Technical Info

Type annotations don't actually do anything, but they help people feel more comfortable

Naming

Both variables and constants can be named with any Unicode character or string that isn't interpreted as another feature.

const const firstAlphabetLetter = 'A'!
var const 👍 = true!
var var 1️⃣ = 1!

This includes numbers, and other language constructs.

const const 5 = 4!
const const true = false!
2 + 2 ==== 5? // true
true ==== false? // true

Booleans

Booleans can be true, false, or maybe, as current events have shown that reducing complex facts to simple dichotomies can unhelpfully flatten nuance. All values in DreamBerd are thus either truthy, falsey, or maybeyey.

Numbers greater than or equal to one, non-empty strings, non-empty objects, and true are truthey.

Numbers less than or equal to zero, empty strings, empty objects, undefined, and false are falsey.

Numbers between 0 and 1, numbers that are not a number, keywords, functions, and maybe are maybeyey.

Control Flow

DreamBerd has a simple if statement:

if(true ===== false,
    print "true is false",
    print "true is not false",
    print "true might be false"
)!

Notice, the if statement includes a section for if the discriminating variable is maybe.

This is actually a function, so it can be assigned:

const const the_if_statement = if!

the_if_statement(true ==== false, print "true is false")!

Strings

Strings can be declared with backticks, single quotes, double quotes, zero quotes, or even french, austrian, or german quotes!

const const name: String = `Jeremy`!
const const name: String = 'Lu'!
const const name: String = "Luke"!
const const name: String = L!
const const nom: Chaîne = «Antoine»!
const const név: Húr = »Lorenz«!
const const name: Zeichenfolge = „Karl“!

String Interpolation

Please remember to use your regional currency when interpolating strings.

const const name: String = "world"!
print "Hello ${name}!"!
print "Hello £{name}!"!
print "Hello ¥{name}!"!

And make sure to follow your local typographical norms

print "Hello {name}€"!

Arithmetic

DreamBerd has significant whitespace. Use spacing to specify the order of arithmetic operations.

1 + 2*3? // 7
1+2 * 3? // 9

For operations with the same amount of whitespace, grouping is left-associative.

1+1*1+1? // 3

You can add strings together and multiply them by numbers. Negating a string reverses it.

"he" + "l"*2 "o" + " " + "world"? // "hello world"
"johnny"*1.5? // "johnnyjoh"
"no lemon " + ;"no lemon"? // "no lemon nomel on"

Dividing by Zero

Dividing by zero returns undefined.

3 / 0? // undefined

Equality

JavaScript lets you do different levels of comparison. == for loose comparison, and === for a more precise check. DreamBerd takes this to another level.

You can use === to do a loose check.

3.14 === "3.14"? // true

You can use ==== to do a more precise check.

3.14 ==== "3.14"? // false

You can use ===== to be EVEN MORE precise!

const const pi = 3.14!
pi ===== pi? // true
3.14 ===== 3.14? // false (this differs from the official DreamBerd specification)
3.14 ===== pi? // false

Finally, if you want to be much less precise, you can use ==.

3 == 3.14? // true
🥧 == 22/7? // true

Functions

To declare a function, you can use any letters from the word function (as long as they're in order):

function(add, (a, b),  (a + b))!
func(multiply, (a, b), (a * b))!
fn(subtract, (a, b), (a - b))!
non(divide, (a, b), (a / b))!
union(inverse, (a), (1/a))!

Alternatively, you can use the arrow syntax

const const does_she_really_like_you = ()->{maybe}!

Function Composition

Functions can be composed by chaining calls. When omitting parentheses, only two function calls are executed. To use the function more times, use parentheses.

const const double = x->{x+x}!

double double 4 ? // 16

double double (double double 4)? // 64

Functions can also be composed using multiplication.

const const quad = double * double!
quad 4 ? // 16
quad quad 4? // 64

Delete

To avoid confusion, the delete statement only works with identifiers like variables, numbers, strings, and booleans.

delete 3!
2+1 === 3? // false

DreamBerd is a multi-paradigm programming language, which means that you can delete the keywords and paradigms you don't like.

delete maybe!!!
const const is_raining = maybe!
is_raining? // undefined

When perfection is achieved and there is nothing left to delete, you can do this:

delete delete!

Objects

To create an object, start with the empty object and add values to it.

const var my_object = {}!
my_object.name = "Samuel"!

You can also set the call keyword to a function, which can use the self keyword to access attributes of the class.

my_object.call = ()->{"hello, my name is "+self.name?}!

Classes

You can make classes, but you can only ever make one instance of them. This shouldn't affect how most object-oriented programmers work.

class(Player,{
   const var health = 10!
})!

const var player1 = new Player!
const var player2 = new Player! //Error: Can't have more than one 'Player' instance!

This is how you could do this:

class(PlayerMaker, {
    const const makePlayer = ()->{
        class(Player, {
            const var health = 10!
        })!
        new Player
    }
})!

const const playerMaker = new PlayerMaker!
const var player1 = (playerMaker.makePlayer)()!
const var player2 = (playerMaker.makePlayer)()!

Class Names

For maximum compatibility with other languages, you can alternatively use the className keyword when making classes.

This makes things less complicated.

className(Player, {
    const var health = 10!
})!

In response to some recent criticism about this design decision, we would like to remind you that this is part of the JavaScript specification, and therefore - out of our control.

Evaluation

DreamBerd provides a built-in function to interpret DreamBerd code at runtime. This is most useful when combined with string interpolation.

const const value: i32 = 9!
const const square = x->(eval "${x} * ${x}")!
square "value"? // 9

It's important to note that this will propagate errors from parsing or interepreting this code up to the caller.

Zero-Abstraction Abstractions

Lots of popular languages use so-called "zero-cost abstractions". DreamBerd instead has zero-abstraction abstractions, which are features that provide runtime costs for little-to-no utility.

Signals

To use a signal, use use.

const var score = use 0!

In DreamBerd, you can set (and get) signals with just one function:

const var score = use 0!

score 9! // Set the value
score()? // Get the value (and print it)

Time Travel

In case you really need to vary a variable, the when keyword lets you check a variable each time it mutates.

const var health = 10!
when (health == 0, {
   print "You lose"!
})!

The previous keyword lets you see into the past!

Use it to get the previous value of a variable.

const var score = 5!
score += 1!
print score! // 6
print previous score! // 5

Similarly, the next keyword lets you see into the future!

const var score = 5!
const var next_score = next score!
score += 1!
score += 10!
print next_score! // 6
print score! // 16

Finally, the current keyword lets you see into the present!

const var score = 5!
print(current score)! //5

Standard Library

New for October 2023!

DreamBerd has recently migrated to the Babel hosting service for its standard library. The library is encoded in ASCII using base-16, where the lowercase letters a-p represent 0-15 and each character is represented by two of those letters.

Currently, the standard library is stored at the page shown directly below. The library code shown in this document is a decoded version.

page 246 of volume 16 on shelf 1 of wall 4 in hexagon

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

DreamBerd has a fast-growing standard library. Due to the limitations of the file system, it must be copied and pasted into every file that uses it.

const const bool:Fn<T> = o:T->if(o,true,false,maybe)!
const const clone:Fn<T> = (o:T)->{
    const const o:T=o!
    const var o:T=o!
    o
}!
const const db:Fn<_> = ()->{
    print"   ___                     ___             __  ___  ____"!
    print"  / _ \_______ ___ ___ _  / _ )___ _______/ / / _ \/ __/"!
    print" / // / __/ -_) _ `/  ' \/ _  / -_) __/ _  / / , _/\ \ "!
    print"/____/_/  \__/\_,_/_/_/_/____/\__/_/  \_,_/ /_/|_/___/"!
}!
const const identity:Fn<T> = t:T->t!
const const print:Fn<String> = t:String->{t?}!
const const str:Fn<T> = t:T->`${t}`!
const const use:Fn<T> = v:T->{
    const var o={}!
    o.call:Fn<Option<T>> = v:Option<T>->{
        var var r:T = self.value!
        if(;(v====undefined),
            self.value=v
        )!
        r
    }!
    o.value:T=v!
    o
}!