Difference between revisions of "REQUIRE()"
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// Close all active API procedure library files | // Close all active API procedure library files | ||
set library to | set library to | ||
| + | |||
| + | // dynamically load a module | ||
| + | local mylib = require(“mylibrary.prg”) | ||
| + | Mylib.name() | ||
| + | Mylib.var = “hello world” | ||
</code> | </code> | ||
Revision as of 20:19, 10 March 2021
Contents
Purpose
Load a library file built with the Lianja C Extensions API, a Lianja procedure library or a JavaScript (.js), PHP (.php) or Python (.py) file
Syntax
REQUIRE(<expC>)
See Also
CLOSE PROCEDURE, DO, FUNCTION, INCLUDE(), INCLUDE_ONCE(), LIST PROCEDURE, PARAMETERS, PROCEDURE, RELEASE LIBRARY, REQUIRE_ONCE(), SET LIBRARY
Description
The REQUIRE() function opens the specified, scans the contents of it, and records the names and positions of the procedures defined within it. The <expC> is the name of the library file, which can be a Lianja API or Lianja procedure library file or a JavaScript (.js), PHP (.php) or Python (.py) file. If the file extension is not stated, '.so' is assumed on Linux. To load a Lianja procedure or class library file, the '.prg' or '.dbo' file extension must be included. You can place as many procedures or classes as you want in a procedure library file.
The SET LIBRARY TO command, without any filename specified, closes all active C Extensions library files. A closed library file discards any knowledge of where the procedures within reside. The RELEASE LIBRARY <library filename> command can be used to close an individual C Extensions library file.
The SET PROCEDURE and CLOSE PROCEDURE commands can also be used to handle Lianja procedure library files.
The active procedures and functions can be listed with the LIST or DISPLAY PROCEDURE commands.
In Lianja 6 dynamically loadable modules are now supported.
This provides OO encapsulation for existing code so that loading a library does not "pollute" the namespace and create potential problems due to name clashes.
Use the require() function to dynamically load a library and reference its public variables and procedures/functions in an OO manner.
The filename specified as the argument to the require() function must exist in the Lianja path or be prefixed with a special prefix e.g lib:/ or thirdpartylibs:/
Example
// Open Samples.so API procedure library require("Samples") // Close pdf.so API procedure library release library pdf.so // Close all active API procedure library files set library to // dynamically load a module local mylib = require(“mylibrary.prg”) Mylib.name() Mylib.var = “hello world”
