Auto-Corrector
An auto-corrector is a language service that typically occurs after text changes and can fix up things like character casing.
A pre-built class is available that can help add automatic case correction to a language.
Basic Concepts
Auto-correctors are classes implementing IAutoCorrector with an AutoCorrect method that performs some modification of text over the specified range.
AutoCorrectorBase Class
An abstract AutoCorrectorBase class is available that implements IAutoCorrector, providing a great starting point for an auto-corrector. This class watches for document text changes and caret moves. If a document text change spans multiple lines, auto-correct is immediately called for the affected lines. If a document text change occurs on a single line, a flag is set. When the caret moves to a new line, auto-correct is called for the previously modified line.
All the an inheritor class needs to implement is an override for the AutoCorrect method to perform the actual auto-correct logic.
AutoCaseCorrector Class
The AutoCaseCorrector class inherits AutoCorrectorBase and implements auto-correct behavior to cycle over the tokens in the specified range.
The GetCaseCorrectText method is passed the current ITextSnapshot and the IToken to examine. It returns a string value if there is some auto-correction of text that should be made. It can return null to indicate no auto-correct change is necessary.
The method is virtual and its default implementation looks to see if the token is an IMergableToken. If so, it checks to see if the token didn't match its source lexical pattern in a case sensitive way. In that scenario, it returns the IMergableToken.AutoCaseCorrectText value.
Thus the AutoCaseCorrector can be registered on any language that uses a dynamic lexer and it will work out of the box to provide case correction functionality. Note that the lexer must have some lexical patterns' case sensitivities marked as auto-correct.
For more advanced programmatic lexers, as long as they are mergable, this class can still provide a good base for an auto-case corrector. Simply override the GetCaseCorrectText method and implement logic to determine if the token was a case sensitive match. If it wasn't, return the auto-case corrected text to use.
Registering with a Language
Any object that implements IAutoCorrector can be associated with a syntax language by registering it as an IAutoCorrector service on the language.
This code creates an AutoCaseCorrector object and registers it with the syntax language that is already declared in the language variable:
AutoCaseCorrector corrector = new AutoCaseCorrector();
language.RegisterAutoCorrector(corrector);
Note
The SyntaxLanguageExtensions.RegisterAutoCorrector method in the code snippet above is a helper extension method that gets added to ISyntaxLanguage objects when the ActiproSoftware.Text namespace is imported. See the Service Locator Architecture topic for details on registering and retrieving various service object instances, both via extension methods and generically, as there are some additional requirements for using the extension methods.
Disabling Auto-Correct
Auto-correct can be disabled within a SyntaxEditor instance by setting the SyntaxEditor.IsAutoCorrectEnabled property to false.