InferLang

Compiler of a simple language featuring local type inference and targeting Common Language Runtime.

Syntax

Modules

All code in InferLang is placed in modules. Module namespaces can be specified with module keyword.

module ExampleModule
module Company::Project::Component::ExampleModule2

If the module namespace is not given it will be set based on file location and name. For example if the code is placed in file ProjectRoot/A/B/Program.ifr and the compiler is launched in ProjectRoot the module namespace will be: A::B::Program.

Functions

Functions are defined with fun keyword. Here is a function taking parameters of types int and float and returning string:

fun exampleFunction1 (a : int) (b : float) : string
{
    return a.ToString() + b.ToString();
}

Types of parameters need to be specified. The return type can be omitted. The compiler will be able to infer it.

fun exampleFunction2 (a : int) (b : float)
{
    return a.ToString() + b.ToString();
}

Built-in types

• bool
• int
• float
• string
• void

Local variables

Variables are defined using var. Constants are defined using val. The compiler can infer types of variables and constants or they can be specified.

var c = 42;
val d = calculateD();
var e : int = computeE(c, d);

Lists

val stringList = ["a","b","c"];
val intList = [1;2;3]
val objList = [1;"A";3.2]

Classes

Classes can be created using class keyword. Example:

class Animal 
{
    val _noise : string

    construct (noise : string)
    {
        _noise = noise;
    }

    fun MakeNoise
    {
        System::Console:.WriteLine(_noise);
    }
}

class Dog : Animal
{
    construct : ("Hau!")
    {
    }
}

class Cat : Animal
{
    construct : ("Miau!")
    {
    }
}

class Duck : Animal
{
    construct : ("")
    {
    }

    fun MakeNoise
    {
        System::Console:.WriteLine("Kwak!");
    }
}

Class members need to be declared in the following order:

1. Fields
2. Constructors (defined with construct keyword)
3. Functions

All functions are virtual and can be overloaded in inheriting classes.

Type Inference

Type inference is looking for a least upper bound of types.

Closest common ancestor of int, string and float is obj:

val objList = [1;"A";3.2]

Closest common ancestor type of Dog and Cat is Animal:

fun createAnimal(animalType : string)
{
    if(animalType == "dog")
        return new Dog();
    else if(animalType == "cat")
        return new Cat();
}

Setup and compiler usage

Compile.exe need to be placed in the root of the source project. Compile.exe --help prints available options:

USAGE: Compile.exe [--help] [--output <path>] [--outputtype <exe|dll>] [--referenceddlls [<paths>...]] [--printir]
                    [<path>...]

SOURCEFILES:

    <path>...             source file paths.

OPTIONS:

    --output, -o <path>   output path.
    --outputtype, -O <exe|dll>
                          output type.
    --referenceddlls, -R [<paths>...]
                          referenced dll paths
    --printir, -S         print intermediate representation
    --help                display this list of options. 

When source file paths are not provided it automatically compiles all files with .ifr extension:

polymorphism> .\Compile.exe
No input files specified. Searching for .ifr files:
Base directory: C:\Users\Karol\Desktop\compiler\samples\polymorphism\
classes.ifr
Writing output file to: Program.exe