Project

Versioning

To manage you greycat version on a per project specify the library std version in your project.gcl

// project.gcl
@library("std", "7.0.1304-dev");

greycat install

This will create two directories

lib : will contain the libraries bin : will contain the greycat executable, from which you should execute your greycat application

GreyCat Modules

• GreyCat code is organized by modules which are basically files with the .gcl extension
• The main module of any GreyCat project must be named project.gcl (At the top level directory of the project)
• A module can contain several global variables, functions, enums and type definitions

For example here is a bank.gcl module:

// Global module variables
var countries_by_name: nodeIndex<String, node<Country>>; // Global index to index all countries

// Global module functions
fn printStats() {
    // Some global module function called printStats
}

// Several Enum and Type definitions
enum TransactionType {
    online("online");
    transfer("transfer");
}
type Country {
    name: String;
    banks: nodeIndex<String, node<Bank>>;
}
type Bank {
    name: String;
    location: geo;
}

All content from a module is automatically accessible in the whole project

New module called other.gcl

fn otherStuff() {
    // function defined in bank.gcl
    printStats();

    // type defined in bank.gcl
    var bank = Bank {
        name: "BGL"
        location: 49.613764lat6.127357lng,
    };

    // var defined in bank.gcl
    var country = countries_by_name.get("France");
}

GreyCat project structure

• By convention, we organize GreyCat modules in the following directory structure:

• At the top level there is the project.gcl file and server folder.
• /server folder represents the backend
• /server/src contains the backend source code:
  • /server/src/model : core data model for the domain
  • /server/src/api : application programming interface (for frontend - backend communication)
  • /server/src/edi : electronic data interface (for data importer/exporter)
• /server/test contains the backend testing code