Verse Interpreter

This solution describes an implemented interpreter for the functional-logic language Verse, proposed by Epic Games.

How to Use

The application call needs command-line arguments according to the following pattern:

    {renderMode} {resultMode} {command}

    {renderMode}: -default | -silent | -debug
    {resultMode}: -one | -all
    {command}: -code "your code here" | -interactive | -file "your file path here"

Implemented Features

For detailed information about the supported expressions take a quick look into the "Verse.g4" file. Some of them are:

• Comments are supported beginning with a '#'.
• Assignment using "x := e"
• Choice as "e1 | e2"
• Failing choice as "false?"
• Choice as range expressions using "Integer..Integer" can be used to create choices with all numbers between the range.

Missing Features

• Recursion is not working.
• ForDo uses flatMap instead of map, therefore not behaving entirely correct.
• Type system is missing.
• Strings support only lower case characters without special characters and only support concatenation via addition and comparison by its length.

Collection of Verse Programs

Visit the Verse-Interpreter.Test project for samples with expected results.

Deviations from the Verse Syntax or Verse Paper

• Rule Exi-Swap is implemented but not used because the execution strategy infinite-loops when using it.
• one{} equivalent to for{} can be used to wrap expressions for retrieving a single value.
• Functions are not implemented as they are only syntactical sugar for lambdas.