LazHelpIntf unit

Defines base classes used in the LCL help system.

lazhelpintf.pas contains types, classes, and routines used in the LCL help system. It defines various base classes that provide the interface for the help system. Many of the methods in these classes are defined as abstract virtual methods, and must be implemented in more specialized descendent classes.

Author: Mattias Gaertner

Classes and records

`THelpBasePathObject`	class	Stores the base file path for help databases.
`THelpBaseURLObject`	class	Stores the base URL for topics in help databases.
`THelpDatabase`	class	Provides support for integrating a collection of related help topics with a table of contents.
`THelpDatabases`	class	Implements support for accessing and maintaining registered help database classes in the help system.
`THelpDBIClass`	class
`THelpDBIMessage`	class
`THelpDBISourceDirectories`	class
`THelpDBISourceDirectory`	class
`THelpDBISourceFile`	class
`THelpDBItem`	class
`THelpNode`	class	.
`THelpNodeQuery`	class
`THelpNodeQueryList`	class
`THelpQueryItem`	class
`THelpQueryNode`	class
`THelpViewer`	class	Base class for help viewers used in the LCL help system.
`THelpViewers`	class	Used to access and maintain registered help viewers for the LCL help system.
`TPascalHelpContext`	record	Record type used to represent a Pascal help context and its descriptor.
`TPascalHelpContextList`	class	Implements a list for Pascal help contexts.

Procedures and functions

`AppendURLPathDelim`	function	Includes a trailing path delimiter in the file path for the specified URL.
`ChompURLParams`	function	Removes URL parameters from the specified URL.
`CombineURL`	function	Builds a URL using the specified scheme, path, and parameter values.
`CreateLCLHelpSystem`	procedure	Ensures the HelpDatabases and HelpViewers variables are initialized for use in the LCL help system.
`CreateListAndAdd`	procedure	Ensures that a TList has been created before adding the specified object instance.
`CreateNodeQueryListAndAdd`	procedure	Ensures the THelpNodeQueryList instance has been created prior to adding the specified help query item.
`ExtractURLDirectory`	function	Gets directories in the file path for the specified URL.
`ExtractURLPath`	function	Gets the path information from the specified URL.
`FilenameToURL`	function	Gets the URL with file path information for the specified file name.
`FilenameToURLPath`	function
`FindURLPathEnd`	function	Gets the position in the URL for the final character in the file path.
`FindURLPathStart`	function	Gets the position in the URL where the file path is located.
`FreeLCLHelpSystem`	procedure	Frees the HelpDatabases and HelpViewers used in the LCL help system.
`FreeUnusedLCLHelpSystem`	procedure	Frees unreferenced Help databases and viewers in the LCL help system.
`IsFileURL`	function	Determines if the specified URL uses the 'file:' URL scheme.
`SplitURL`	procedure	Separates a URL into its scheme, path, and parameter component values.
`TrimUrl`	function	Removes leading or trailing spaces in the file path for the specified URL.
`TrimURLPath`	function	Removes leading and trailing whitespace in the file path for the specified URL.
`URLFilenameIsAbsolute`	function	Indicates if the specified URL contains an absolute file path.
`URLPathToFilename`	function

Types

`THelpDatabaseClass`	type	Class reference for the THelpDatabase type.
`THelpNodeType`	enumeration	Enumerated type that identifies the method(s) available to locate a help topic.
`THelpViewerClass`	type	Class reference used to create instances of the help viewer.
`TOnHelpDBFindViewer`	procedure type
`TPascalHelpContextPtr`	type
`TPascalHelpContextType`	enumeration	Enumerated type with values representing Pascal help contexts.

Variables

`HelpDatabases`	variable	Contains the list of registered help databases used in the Lazarus IDE.
`HelpViewers`	variable	Contains the list of registered help viewers used in the Lazarus IDE.

Uses

An experiment, built from development snapshots. Not the official Free Pascal or Lazarus documentation.