Occam Furtle

Occam's Furtle language.

Contents

• Introduction
• Installation
• Example
• Building
• Contact

Introduction

Furtle is a dynamically but nonetheless strictly typed, pure functional language meant primarily for traversing parse trees. It is called from Nominal thus...

Rule (FreeVariable)
  Premise
    @isVariableFree(u, P)
  Conclusion
    u is free in P

...and looks like, for example:

String variableNameFromTermNode(Node termNode) {
  Node variableNameTerminalNode = nodeQuery(termNode, "/term/variable/@name");
  
  String variableName = 

    If (variableNameTerminalNode != null) {
      { String content As variableName } = variableNameTerminalNode;
    
      Return variableName;
    } 

    Else 
      ""
  ;
  
  Return variableName;
}

Despite its strict typing it has a somewhat JavaScripty feel. It supports array and object destructuring, for example. It also supports "some", "every" and "reduce" functionality as well as ternaries:

String boundVariableNameFromStatementChildNodes(Nodes statementChildNodes) {
  [ Node terminalNode ] = statementChildNodes;

  { String content } = terminalNode;

  String boundVariableName = 

    If ((content == "∀") || (content == "∃")) {
      [ _, Node argumentNode ] = statementChildNodes;

      String boundVariableName = boundVariableNameFromArgumentNode(argumentNode);
  
      Return boundVariableName;
    }
    Else
     ""
  ;

  Return boundVariableName;
}

It is nascent at this stage, but is expected to grow.

Installation

With npm:

npm install occam-furtle

You can also clone the repository with Git...

git clone https://github.com/djalbat/occam-furtle.git

...and then install the dependencies with npm from within the project's root directory:

npm install

Example

There is a small development server that can be run from within the project's directory with the following command:

npm start

The example will then be available at the following URL:

http://localhost:8888

The source for the example can be found in the src/example.js file and corresponding src/example folder. You can rebuild them on the fly with the following command:

npm run watch-debug

The development server will reload the page whenever you make changes.

One last thing to bear in mind is that this package is included by way of a relative rather than a package import. If you are importing it into your own application, however, you should use the standard package import.

Building

Automation is done with npm scripts, have a look at the package.json file. The pertinent commands are:

npm run build-debug
npm run watch-debug

Contact

• [email protected]