Basics

Overall Eyot's syntax should be familiar to someone used to the broad family of languages inheriting syntax from C (e.g. C++, C#, Go, Java, Rust). I've tried to keep the syntax minimal, and unsurprising, to someone familiar with some language in that family. This makes Eyot easy to implement and learn, and constrains my experimentations to Eyot's distinguishing feature - the way it allows you to interact with the GPU using Workers.

Variables

Mutable variables can be assigned with let. The type is inferred

let x = 12
print_ln(x)

Please note that print_ln is a builtin function for debug printing while developing Eyot. It is unlikely to go anywhere in the near future, but it will eventually move to the standard library.

Global variables are disallowed for now as they are complex to share with the GPU.

Integers

The only integer type so far is i64, which denotes a 64 bit signed integer.

Float

Currently there are 32 and 64 bit floating point types f32 and f64 respectively. Due to limitations in the standard profile of OpenCL, only 32 bit floats are allowed in GPU code. I hope to lift this restriction by moving to a different back end on day.

1.0 is an f64 literal, and 1.0f is an f32 literal.

Boolean

bool is a boolean type, of which true and false represent the only two values.

Eyot has the usual numerical comparison operators (==, !=, <, >, <=, >=) , all of which return bool.

bool values can be negated with the not keyword

Vector

A vector (flexible array) of values is denoted by square brackets around the type it contains. E.g. [i64]. Literals are denoted by braces after the type

let x = [i64] { 1, 2, 3, 4 }

Values can be read and set using square brackets

x[3] = 5
print_ln(x[3])

Additionally vectors support the following builtin functions - x.length() returns the number of elements - x.resize(20) resizes the vector to have space for 20 slots - x.append(1) would add a new value to the vector

Strings and Characters

String literals are created with quotes

let species_name = "dog"

They can be concatenated with the + function

let concatenated = "x" + "y"
print_ln(concatenated)

And similar to vectors they support .length() and the access operator ([]). Please note that these operators work in terms of Unicode Scalar Values. For now the details of how they may be stored are opaque to users of Eyot, and the runtime is free to chose.

The access operator, [], takes the code point index as a value, and returns a char type, which is a type sufficient to represent all Unicode code points