Language Statement Summary

Language is the primary statement that controls a language definition. The language statement occurs within a command script whose startup tag is Metalanguage. When gmBasic encounters a command script with the Metalanguage startup tag in suspends its normal operation in expectation of processing its language definition. The standard language specification file starts as follows

The messages file contains a Messages statement which defines the error messages used by gmBasic when it processes statements, including its own language definition. The language statement must be preceded by the Messages statement, but may not be preceded by any other statement. The final output of the Metalanguage command script is a virtual binary information file called vb7lang.vbi which must be stored in the home directory of gmBasic which, by default, is the directory that contains the actual executable file. See the gmCL discussion for details on controlling how gmBasic starts up.

The attributes of the Language statement are as follows:

The substatements of the Language statement are as follows:

The script errors associated with the Language statement are as follows:

Overriding VB6 Language Classes

The language file, among other things, contains generic descriptions and migrations for the common controls defined within the VB6 libraries that were loaded implicitly by Visual Basic:

The bulk of these generic migrations are probably sufficient for most migration projects; however the three controls -- DriveListBox, DirListBox, and FileListBox -- do not have direct .NET equivalents and therefore are migrated to the Microsoft.VisualBasic.Compatibility.VB6 namespace. The use of this namespace raises a red flag for many migrations. The distribution of gmBasic contains a reference script Language.std.xml that will replace the migration of these three controls with a standard COM/IDF translation into a MigrationSupport.UI migration. These translations will contain the standard stubbed implementations that can then be completed by the migration team. To use this file simply place it in the IDF search path of the migration.

The only special characteristic of the Language.std.xml reference script is that it is auto-loaded by gmBasic immediately before it performs a compilation. See the discussion of the LoadEnvironment statement for details. The file itself is a source file, so it can be edited by the user if desired. In addition, the std portion of the name is the sysid of the translation script; therefore, alternative migrations can be specified that are triggered by different ids. Finally, completely independent reference scripts can be authored and loaded via the Reference statement. During a given translation run, and reference script class whose name matches and internal control class name and that has the additional adornment migStatus="OverrideUser" will override the specification of the internal control. Thus, an entry

overrides the definition of the internal DriveListBox control in the language file; while, the entry

as taken from the Excel.exe.xml reference script does not override the internal TextBox control in the language file.

To begin the external migration of a language control begin by extracting its class definition from the source language file vbcontrols.xml and placing it in a new reference script. Next, remove all the opcode attributes and add migStatus="OverrideUser" to all class definitions. There may also a few refactoring specifications that can be simplified and removed. In the case of the Language.std.xml, properties that had the adornment status="Dimen" where simply changed to have the Collection type; and some properties that had individual GetSetLet specifications were simplified.