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# Foreign !:

All J interfaces with the environment are provided by the conjunction`!:` (foreign). In most cases the foreign result is a verb that provides a specific service. The left argument of foreign selects a general family of services and the right argument selects a specific service from that family. The families of services selected by the left argument are:

0 | Scripts
1 | Files
2 | Host Commands
3 | Storage Types
4 | Name Classes and Lists
5 | Representations
6 | Time
7 | Space
9 | Global Parameters
11 | Windows
13 | Debug
15 | Dynamic Link Library
18 | Locales
128 | Numerical Functions

The foreign conjunction is documented in the J Dictionary and in the J Online Documentation.

You have run across a few specific uses of the foreign conjunction in earlier sections.

The derived verb `9!:11` was used in the Print precision section. The `9` selects the Global Parameters family and the `11` gives a derived verb that sets the print precision.

The load verb uses `0!:0` to load scripts. The left argument selects the scripts family. Look up the definition. The `0` right argument is treated as three decimal digits `000` and therefore executes sentences from a file, stops on an error, and is silent (does not display sentences or results).

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