REBOL 3 Functions: import

Contents

Summary

Locate, load, make, and set local bindings for module.

Description

The import function is used to import modules into your runtime environment. For a full description see the modules: loading modules section of this documentation.

For example, you can write:

import 'mysql

and the system will search for the mysql module.

You can also use a filename or URL for the module identifier:

import %mysql.r

import http://www.rebol.com/mods/mysql.r

Return value

When successful, the import function returns a module! datatype as its result.

This allows you to write:

mysql: import 'mysql

Now, the mysql variable can be used to refer to values within the mysql module.

For example the module value is used here to reference a function:

mysql/open-db %my-database.sql

See below for more.

Useful refinements

Like the header needs field, the import function also lets you specify a version and a checksum.

These are all supported:

import/version mysql 1.2.3

import/check mysql #{A94A8FE5CCB19BA61C4C0873D391E987982FBBD3}

import/version/check mysql 1.2.3 #{A94A8FE5CCB19BA61C4C0873D391E987982FBBD3}

When to use IMPORT

The benefit of using the import function compared to the needs header field is that the arguments can be variables.

A basic example is:

mod: 'mysql
import mod

Or, something like:

mod-list: [
    mysql 1.2.3
    db-gui 2.4.5
    http-server 1.0.1
]

foreach [id ver] mod-list [
    import/version id ver
]

Related

do   load