Vampa

Development

Dependencies are:

• llvmenv, which you can install with cargo install llvm
• libssl-dev on Debian or openssl on Arch Linux

Other things I needed on Ubuntu 18:

• lib32z1-dev, available through apt

To build, follow these setup instructions and run:

cargo build

Running a program

See Thread with programs that compile and run.

Write your program:

# test.vam

fun three returning i32 = 3;

apply three

Run it:

cargo run --bin vamc ./test.vam && lli ./test.o

MVP

Since the MVP will only deal with integers, I can skip implementing type-checking because everything is an i32. Perhaps I will need to implement a type for functions.

It should include:

• Comments
• All the arithmetic operations
• The ability to declare and define variables of type i32
• The ability to declare functions (with and without body brackets)
• The ability to call functions
• No concept of scope
  • This is not a permanent feature and scope should eventually be implemented
  • A single hash map for all variables
• Variable references

The following program should compile and run:

let first: i32 = 20;
let second: i32 = 22;

fun sum of a: i32 and b: i32 returning i32 = + a b;
fun sum_with_brackets of a: i32 and b: i32 returning i32 = { + a b };

apply sum first second; # 42
apply sum 10 12; # 22
apply sum { 10 } 10; # 20
apply sum { + 2 2 } 5; # 9

General characteristics

• Expression-oriented
• Immutable by default
• Strictly typed
• Supporting type inference
• Compiled using LLVM as a backend

Basic syntax

Vampa is case-sensitive and uses the Unicode character set.

• Comments can be inline or block
  • Inline comments
  • Block commments

# An inline comment

#[
# Hey there
# This is my block comment
#
# #[
# # This is a nested block comment
# # Hey there
# #]
#]

• Statements are terminated by a semicolon
• Makes use of curly brackets {} for blocks
• Identifiers must start with a letter and must not include :
• Variables are declared using let
  • They must be initialized at the time of their declaration
  • They are either in the scope of their module or in the scope of a block

let poem = "The revery alone will do, if bees are few";

• Functions are declared using of to initiate a list of arguments, and and to separate arguments, and then = to start the body of the function, which can have a body {} or a body without brackets

# Using a body without brackets
fun sum of first_number and second_number = + first_number second_number;

# Using a body with brackets, implicitly returning the last expression
fun sum of first_number and second_number = { + first_number second_number };

• Functions calls are preceded by apply and arguments in function calls are delimited with spaces:

let aggregate = apply sum 5 7;

• Blocks can be used to eliminate ambiguity:

let aggregate = apply sum 5 { sum 7 8 };

• Type hints are indicated using a colon :, must be placed next to the identifier they refer to, and can be used:
  • Next to variable identifiers to indicate their type
  • Next to function identifiers to indicate their return type

let poem: string = "The revery alone will do, if bees are few";
fun sum of first: i32 and second: i32 returning i32 = + first second;

• Types are declared using the type keyword.

type Uuid = string;

• Generic types are indicated using square brackets []:

type Five[T] = [5 of T];

Data structures

Scalar types

• Boolean: true and false

Integer types

Floating-point types

• f32
• f64

The boolean type

• true
• false

The character type

It's four bytes in size.

• char

The string type

• string

Compound types

The tuple type

• [char, i32]: a tuple of a char and an i32

The array type

• [5 of char]: an array of length 5 containing chars

Arithmetic operations

These are used in prefix position and can be combined using curly brackets {} to indicate precedence explicitly.

• +
• -
• /
• %
• *

Reserved keywords

• Any variable starting with any symbol that's not a letter
• All the types listed above
• and
• apply
• fun
• let
• of
• returning
• type