(v13) Selectors as function calls
This page applies to Harlequin v13.1r0 and later; and to Harlequin MultiRIP but not Harlequin Core
The selector mechanism is used so that there need only be one agreed entry point in most plugins. This simplifies the plugin interface's requirements: instead of directly calling a number of different functions in the plugin, each of which you would be required to export. Most of them still have to be implemented. The RIP generally only calls the exported PLUGIN and uses the selector protocol to request that the plugin carry out particular operations.
It is simpler, however, to describe a call to the plugin with a particular selector among the arguments as calling that selector. Rather than saying:
The RIP calls the plugin with the selector D_INITIALISE...
It is easier to say this:
The RIP calls D_INITIALISE...
This economical convention is used throughout the manual.