GreyCat Modules

Greycat code is organized by modules which are basically files with the .gcl extension
The main module of any greycat project should 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;
}

Greycat naming convention

Item	Convention	Example
Modules	snake_case	smart_city.gcl
Types / Class / Enum	UpperCamelCase	enum TransactionChannel
Primitive types	camelCase	nodeTime, nodeIndex, int
Functions	camelCase / snake_case *	fn getCities()
Variables / Attributes	camelCase / snake_case *	var cities_by_name: nodeIndex;

For functions and attributes we leave the freedom of camelCase/snake_case according to readability
Usually index names are more readable in snake_case: city_by_location, city_by_name
Simple attributes or variable names are usually in camelCase: firstName, primaryContract

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