Scopes

Scopes are environments in which commands run. Scopes are used to separate the program’s states. For example, variable assignment in one scope can’t overwrite variables inside of another scope.

Syntax

{
        [one or more commands]
}

{
        [one or more commands]
        return [expression];
}

Each scope begins with a { character and ends with a } character. Inside each scope is one or more commands, most of which must be terminated with a ; character. Optionally, a scope may end with a return command.

Behavior

Each scope creates a new namespace for variables, objects, definitions, and relations.

Scopes can be created inside of scopes, in which case the new scope becomes a child scope of the current scope. The parent scopes of the child scope include the current scope and any of the current scope’s parent scopes. A variable, object, definition, or relation is accessible inside of a scope if and only if that entity is in the current namespace or any parent scope’s namespace.

All variables, objects, definitions, and relations in a scopes namespace are destroyed at the end of the scope except in the case in which the scope was created by the context command.

Global scopes are the top-level scopes created at the beginning of program execution. Dependencies can be added within a global scope.

Dependent scopes are child scopes created by the dependent context command. Besides global scopes, dependent scopes are the only scopes in which dependencies can be added.