PACKAGE

Defines the package the module belongs to.

Syntax

PACKAGE package-path

package-path identifies the package for this module. This must be a dot-separated list of of identifiers corresponding to the directory path where the .4gl modules sources and/or .42m p-code modules are located, relative to a top-dir identifying the root of the sources tree.
package-path is case senstivite. The directory names in the file system must match the character case.

Usage

The PACKAGE instruction defines the package path for the current module.

Modules can be grouped into packages, that can then be used by other modules with the IMPORT FGL package-path.* instruction. Modules assigned to a package can also be imported individually with an IMPORT FGL package-path.module-name instruction.

The names in the package-path, as well as the module-name, are case-sensitive.

The package-path must reflect the directory path where the module is located, starting from a top-dir root directory.

Unlike directory paths using OS specific separators, the elements of a package-path must be separated by a dot. For example, if the cleanup.4gl module is located in the top-dir/myutils/sqlutils directory, the PACKAGE specification in cleanup.4gl must be:

PACKAGE myutils.sqlutils

At compile time and at runtime, the FGLLDPATH environment variable can be used to find package modules: A root-path defined in FGLLDPATH will be used to find a package module as root-path/package-path/module-name[.4gl|.42m]. FGLLDPATH typically contains the top-dir of the package path. When compiling or executing the main module from top-dir, no FGLLDPATH needs to be set.

Example

In the directory top-dir/myutils/sqlutils, the source file cleanup.4gl defines:

PACKAGE myutils.sqlutils
PUBLIC FUNCTION clean_temp_data()
    DISPLAY "Cleaning up temp data..."
END FUNCTION

Another module called find.4gl defines:

PACKAGE myutils.sqlutils
PUBLIC FUNCTION find_customer_dups()
    DISPLAY "Searching customer duplicates..."
END FUNCTION

The using module located in top-dir can then import the packages as follows:

IMPORT FGL myutils.sqlutils.*
MAIN
    CALL myutils.sqlutils.cleanup.clean_temp_data()
    CALL myutils.sqlutils.find.find_customer_dups()
END MAIN

If the symbol names available from a given package are not ambigious, the calling module can omit some parts of the the path to the symbol:

IMPORT FGL myutils.sqlutils.*
MAIN
    CALL clean_temp_data()
    CALL find.find_customer_dups()
END MAIN

Compiling from top-dir:

$ fglcomp --verbose main.4gl
[parsing myutils/sqlutils/find.4gl]
[building myutils/sqlutils/find]
[writing myutils/sqlutils/find.42m]
[parsing myutils/sqlutils/cleanup.4gl]
[building myutils/sqlutils/cleanup]
[writing myutils/sqlutils/cleanup.42m]
[parsing main.4gl]
[building main]
[writing main.42m]
...