book

Practical Programming in Tcl and Tk, Fourth Edition

by Ken Jones, Brent Welch

June 2003

Intermediate to advanced

960 pages

20h 55m

English

Pearson

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Copyright
Dedication
List of Examples
List of Tables
Preface
Why Tcl?Tcl and Tk VersionsExtending Tcl and TkTcl on the World Wide WebFtp ArchivesNewsgroupsWho Should Read This BookHow to Read This BookOn-line ExamplesTypographic ConventionsHot TipsBook OrganizationWhat's New in the Fourth EditionOther Tcl BooksFirst Edition ThanksSecond Edition ThanksThird Edition ThanksFourth Edition ThanksContact the Author
I. Tcl Basics
1. Tcl Fundamentals
Tcl CommandsHello, World!VariablesCommand SubstitutionMath ExpressionsBackslash SubstitutionGrouping with Braces and Double QuotesSquare Brackets Do Not GroupGrouping before SubstitutionGrouping Math Expressions with BracesMore Substitution ExamplesProceduresA Factorial ExampleMore about VariablesFunny Variable NamesThe unset CommandUsing info to Find Out about VariablesMore about Math ExpressionsCommentsSubstitution and Grouping SummaryFine PointsReferenceBackslash SequencesArithmetic OperatorsBuilt-in Math FunctionsCore Tcl Commands
2. Getting Started
The source CommandUNIX Tcl ScriptsWindows Start MenuMacintosh OS 8/9 and ResEditMacintosh OS XThe console CommandCommand-Line ArgumentsCommand-Line Options to WishPredefined Variables
3. The Guestbook CGI Application
A Quick Introduction to HTMLCGI for Dynamic PagesThe guestbook.cgi ScriptUsing a Script Library FileBeginning the HTML PageSample Output of the CGI ScriptUsing a Tcl Array for the DatabaseDefining Forms and Processing Form DataThe newguest.html FormThe ncgi and cgi.tcl PackagesThe newguest.cgi ScriptUsing Tcl Scripts to Store DataHandling Errors in CGI ScriptsNext Steps
4. String Processing in Tcl
The string CommandString IndicesStrings and ExpressionsString MatchingCharacter ClassesMapping StringsThe append CommandThe format CommandThe scan CommandThe binary CommandFormat TemplatesExamplesBinary Data and File I/ORelated Chapters
5. Tcl Lists
Tcl ListsConstructing ListsThe list commandThe lappend CommandThe lset CommandThe concat CommandGetting List Elements: llength, lindex, and lrangeModifying Lists: linsert and lreplaceSearching Lists: lsearchSorting Lists: lsortThe split CommandThe join CommandRelated Chapters

6. Control Structure Commands
If Then ElseSwitchComments in switch CommandsWhileForeachMultiple Loop VariablesMultiple Value ListsForBreak and ContinueCatchCatching More Than ErrorsErrorReturn
7. Procedures and Scope
The proc CommandChanging Command Names with renameScopeThe global CommandCall by Name Using upvarVariable Aliases with upvarAssociating State with DataNamespaces and upvarCommands That Take Variable Names
8. Tcl Arrays
Array SyntaxComplex IndicesArray VariablesThe array CommandConverting Between Arrays and ListsPassing Arrays by NameBuilding Data Structures with ArraysSimple RecordsA StackA List of ArraysA Simple In-Memory DatabaseAlternatives to Using Arrays
9. Working with Files and Programs
Running Programs with execThe auto_noexec VariableLimitations of exec on WindowsAppleScript on MacintoshThe file CommandCross-Platform File NamingBuilding up Pathnames: file joinChopping Pathnames: split, dirname, tailManipulating Files and DirectoriesCopying FilesCreating DirectoriesSymbolic and Hard LinksDeleting FilesRenaming Files and DirectoriesFile AttributesInput/Output Command SummaryOpening Files for I/OOpening a Process PipelineExpectReading and WritingThe puts and gets CommandsThe read CommandPlatform-Specific End of Line CharactersRandom Access I/OClosing I/O ChannelsThe Current Directory — cd and pwdMatching File Names with globExpanding Tilde in File NamesThe exit and pid CommandsEnvironment VariablesThe registry Command
II. Advanced Tcl
10. Quoting Issues and Eval
Constructing Code with the list CommandThe eval CommandCommands That Concatenate Their ArgumentsCommands That Use CallbacksCommand Prefix CallbacksConstructing Procedures DynamicallyExploiting the concat inside evalUsing eval in a Wrapper Procedure.Correct Quoting with evalThe uplevel CommandThe subst CommandString Processing with subst
11. Regular Expressions
When to Use Regular ExpressionsAvoiding a Common ProblemRegular Expression SyntaxMatching CharactersCharacter SetsQuantifiersAlternationAnchoring a MatchBackslash QuotingMatching PrecedenceCapturing SubpatternsAdvanced Regular ExpressionsCompatibility with Patterns in Tcl 8.0Backslash Escape SequencesCharacter ClassesNongreedy QuantifiersBound QuantifiersBack ReferencesLook-aheadCharacter CodesCollating ElementsEquivalence ClassesNewline Sensitive MatchingEmbedded OptionsExpanded SyntaxSyntax SummaryThe regexp CommandA Pattern to Match URLsBugs When Mixing Greedy and Non-Greedy QuantifiersSample Regular ExpressionsThe regsub CommandTransforming Data to Program with regsubURL DecodingCGI Argument ParsingDecoding HTML EntitiesA Simple HTML ParserStripping HTML CommentsOther Commands That Use Regular Expressions
12. Script Libraries and Packages
Locating Packages: The auto_path VariableUsing PackagesLoading Packages AutomaticallyPackages Implemented in C CodeSummary of Package LoadingThe package CommandLibraries Based on the tclIndex FileThe unknown CommandHow Auto Loading WorksDisabling the Library Facility: auto_noloadInteractive ConveniencesAuto ExecuteHistoryAbbreviationsTcl Shell Library EnvironmentLocating the Tcl Script Librarytcl_findLibraryCoding StyleA Module Prefix for Procedure NamesA Global Array for State VariablesThe Official Tcl Style Guide
13. Reflection and Debugging
The clock CommandThe info CommandVariablesProceduresThe Call StackCommand EvaluationScripts and the LibraryVersion NumbersExecution EnvironmentCross-Platform SupportTracing Variables and CommandsCommand TracingRead-Only VariablesCreating an Array with TracesInteractive Command HistoryHistory SyntaxA Comparison to C Shell History SyntaxDebuggingTcl Dev KitDebugger with CoverageCheckerCompilerTclAppTcl Service ManagerInspectorOther ToolsThe tkcon ConsoleCritclThe bgerror CommandThe tkerror CommandPerformance TuningTime stamps in a LogThe Tcl Compiler
14. Namespaces
Using NamespacesNamespace VariablesQualified NamesCommand LookupNested NamespacesImporting and Exporting ProceduresCallbacks and NamespacesIntrospectionThe namespace CommandConverting Existing Packages to use Namespaces[incr Tcl] Object Systemxotcl Object SystemNotesNames for Widgets, Images, and InterpretersThe variable command at the global scopeAuto Loading and auto_importNamespaces and uplevelNaming QuirksMiscellaneous
15. Internationalization
Character Sets and EncodingsThe System EncodingFile Encodings and fconfigureScripts in Different EncodingsUnicode and UTF-8The Binary EncodingConversions Between EncodingsThe encoding CommandMessage CatalogsSpecifying a LocaleManaging Message Catalog FilesMessage Catalogs and NamespacesThe msgcat package
16. Event-Driven Programming
The Tcl Event LoopThe after CommandThe fileevent CommandThe vwait CommandThe fconfigure CommandNonblocking I/OThe fblocked CommandBufferingEnd of Line TranslationsEnd of File CharacterSerial DevicesCharacter Set EncodingsConfiguring Read-Write Channels
17. Socket Programming
Networking Extensions for TclScottyStandard Tcl LibraryHTTPClient SocketsClient Socket OptionsServer SocketsServer Socket OptionsThe Echo ServiceFetching a URL with HTTPProxy ServersThe HEAD RequestThe GET and POST RequestsThe fcopy CommandThe http Packagehttp::confighttp::geturlhttp::formatQueryhttp::register and http::unregisterhttp::resethttp::cleanupBasic Authentication
18. TclHttpd Web Server
Integrating TclHttpd with Your ApplicationTclHttpd ArchitectureAdding Code to TclHttpdCustom Main ProgramsDomain HandlersConnection State and Query DataThe html and ncgi PackagesReturning ResultsApplication Direct URLsUsing Query DataReturning Other Content TypesDocument TypesHTML + Tcl TemplatesWhere to Put Your Tcl CodeTemplates for Site StructureUsing Variables for Important Site InformationForm HandlersApplication Direct HandlersTemplate Form HandlersSelf-Posting FormsThe html PackageProgramming ReferenceStandard Application Direct URLsStatusDebuggingSending EmailThe TclHttpd DistributionQuick StartInside the DistributionServer ConfigurationCommand Line ArgumentsServer Name and PortUser and Group IDWebmaster EmailDocument RootOther Document SettingsDocument TemplatesLog FilesCGI Directories
19. Multiple Interpreters and Safe-Tcl
The interp CommandCreating InterpretersThe Interpreter HierarchyThe Interpreter Name as a CommandUse list with interp evalSafe InterpretersCommand AliasesAlias IntrospectionHidden CommandsSubstitutionsI/O from Safe InterpretersThe Safe BaseSecurity PoliciesLimited Socket AccessLimited Temporary FilesSafe after Command
20. Safe-Tk and the Browser Plugin
Tk in Child InterpretersEmbedding Tk WindowsSafe-Tk RestrictionsThe Browser PluginThe embed_args and plugin VariablesExample PluginsSetting Up the pluginSecurity Policies and Browser PluginThe Browser PackageConfiguring Security PoliciesThe config/plugin.cfg FilePolicy Configuration FilesSecurity Policy FeaturesCreating New Security Policies
21. Multi-Threaded Tcl Scripts
What are Threads?Thread Support in TclObtaining a Thread-Enabled Tcl InterpreterUsing Extensions in Multi-Threaded ScriptsGetting Started with the Thread ExtensionCreating ThreadsCreating Joinable ThreadsSending Messages to ThreadsSynchronous Message SendingAsynchronous Message SendingPreserving and Releasing ThreadsError HandlingShared ResourcesManaging I/O ChannelsAccessing Files from Multiple ThreadsTransferring Channels between ThreadsShared VariablesMutexes and Condition VariablesMutexesCondition VariablesThread PoolsThe Thread Package CommandsThe thread NamespaceThe tsv NamespaceThe tpool Namespace
22. Tclkit and Starkits
Getting Started with TclkitInside a StarkitDeploying Applications as StarkitsVirtual File SystemsAccessing a Zip File Through a VFSUsing sdx to Bundle ApplicationsCreating a Simple StarkitExamining a StarkitStandard Package OrganizationCreating a StarpackExploring the Virtual File System in a StarkitCreating tclhttpd.kitCreating a Shared StarkitMetakitMetakit Data ModelExamining a Metakit DatabaseCreating a Metakit ViewStoring Application Data in a StarkitWikit and the Tcler's WikiMore IdeasDocument BundlesSelf-Updating ApplicationsSimple Installers
III. Tk Basics
23. Tk Fundamentals
Hello, World! in TkNaming Tk WidgetsConfiguring Tk WidgetsTk Widget Attributes and the Resource DatabaseThe Tk Manual PagesSummary of the Tk CommandsWidget CommandsWidget Manipulation CommandsSupport ProceduresOther Widget SetsBLTTix[incr Tk] and [incr Widgets]BWidgetsTkTable
24. Tk by Example
ExecLogWindow TitleA Frame for ButtonsCommand ButtonsA Label and an EntryKey Bindings and FocusA Resizable Text and ScrollbarThe Run ProcedureThe Log ProcedureThe Stop ProcedureCross-Platform IssuesThe Example BrowserMore about Resizing WindowsManaging Global StateSearching through FilesCascaded MenusA Read-Only Text WidgetA Tcl ShellText Marks, Tags, and BindingsMultiple InterpretersNative Look and Feel
25. The Pack Geometry Manager
Packing toward a SideShrinking Frames and pack propagateHorizontal and Vertical StackingThe Cavity ModelPacking Space and Display SpaceThe -fill OptionInternal Padding with -ipadx and -ipadyExternal Padding with -padx and -padyResizing and -expandAnchoringPacking OrderIntrospectionPack the Scrollbar FirstChoosing the Parent for PackingUnpacking a WidgetPacker SummaryThe pack CommandWindow Stacking Order
26. The Grid Geometry Manager
A Basic GridThe -sticky SettingExternal Padding with -padx and -padyInternal Padding with -ipadx and -ipadyMultiple Widgets in a CellSpanning Rows and ColumnsRow and Column ConstraintsRow and Column PaddingMinimum SizeManaging Resize BehaviorUniform ColumnsThe grid Command
27. The Place Geometry Manager
place BasicsThe Pane ManagerParsing Arguments and Maintaining StateSticky Geometry SettingsEvent BindingsManaging the LayoutThe place Command
28. The Panedwindow Widget
Using the PanedwindowManipulating the Pane ContentsProgramming Panedwindow WidgetsPanedwindow Attributes
29. Binding Commands to Events
The bind CommandThe bindtags CommandFocus and Key EventsUsing break and continue in BindingsDefining New Binding TagsEvent SyntaxKeyboard EventsMouse EventsOther EventsBindings on Top-level WindowsModifiersEvent SequencesVirtual EventsGenerating EventsEvent SummaryEvent Command SyntaxEvent Keywords
IV. Tk Widgets
30. Buttons and Menus
Button Commands and Scope IssuesButtons Associated with Tcl VariablesButton AttributesButton OperationsMenus and MenubuttonsA Menu BarSystem MenusPop-Up MenusOption MenusMulticolumn Palette MenusMenu Bindings and EventsKeyboard TraversalMenu Virtual EventsManipulating Menus and Menu EntriesMenu AttributesA Menu by Name PackageMenu Accelerators
31. The Resource Database
An Introduction to ResourcesResource PatternsLoading Option Database FilesAdding Individual Database EntriesAccessing the DatabaseUser-Defined ButtonsUser-Defined MenusApplication and User ResourcesExpanding Variables
32. Simple Tk Widgets
Frames, Labelframes, and Toplevel WindowsAttributes for Frames, Labelframes, and ToplevelsUsing Labelframe WidgetsEmbedding Other ApplicationsToplevel Window StylesThe Label WidgetLabel Width and Wrap LengthLabel AttributesThe Message WidgetMessage AttributesArranging Labels and MessagesThe Scale WidgetScale BindingsScale AttributesProgramming ScalesThe bell Command
33. Scrollbars
Using ScrollbarsThe Scrollbar ProtocolThe Scrollbar set OperationThe xview and yview OperationsThe Scrollbar WidgetScrollbar BindingsScrollbar AttributesProgramming Scrollbars
34. The Entry and Spinbox Widgets
Using Entry WidgetsValidating Entry ContentsTips for Using Entry WidgetsUsing Spinbox WidgetsEntry and Spinbox BindingsEntry and Spinbox AttributesProgramming Entry and Spinbox Widgets
35. The Listbox Widget
Using ListboxesManipulating Listbox ContentsProgramming ListboxesThe Listbox WidgetListbox Bindings and EventsBrowse Select ModeSingle Select ModeExtended Select ModeMultiple Select ModeScroll BindingsListbox Virtual EventsListbox AttributesGeometry Gridding
36. The Text Widget
Text IndicesInserting and Deleting TextIndex ArithmeticComparing IndicesText MarksMark GravityText TagsTag AttributesMixing Attributes from Different TagsLine Spacing and JustificationTab StopsThe SelectionTag BindingsSearching TextEmbedded WidgetsEmbedded ImagesLooking inside the Text WidgetLooking at TagsLooking at MarksDumping the ContentsThe Undo MechanismText Bindings and EventsText BindingsText Virtual EventsText OperationsText Attributes
37. The Canvas Widget
Canvas CoordinatesHello, World!Canvas TagsThe Min Max Scale ExampleCanvas ObjectsCanvas Widget and Canvas Object State OptionsDashed LinesArc ItemsBitmap ItemsImage ItemsLine ItemsOval ItemsPolygon ItemsRectangle ItemsText ItemsWindow ItemsCanvas OperationsGenerating PostscriptCanvas AttributesHintsScreen Coordinates vs. Canvas CoordinatesLarge Coordinate SpacesScaling and RotationResourcesObjects with Many PointsSelecting Canvas Items
V. Tk Details
38. Selections and the Clipboard>
The Selection ModelThe selection CommandThe clipboard CommandSelection HandlersA Canvas Selection Handler
39. Focus, Grabs, and Dialogs
Standard DialogsMessage BoxFile and Directory DialogsColor DialogCustom DialogsInput FocusThe focus CommandKeyboard Focus TraversalGrabbing the FocusThe tkwait CommandDestroying WidgetsThe focus, grab, tkwait sequencePrompter DialogKeyboard Shortcuts and FocusAnimation with the update Command
40. Tk Widget Attributes
Configuring AttributesSizeBorders and ReliefThe Focus HighlightPadding and AnchorsPutting It All Together
41. Color, Images, and Cursors
ColorsColor PalettesColor ValuesColormaps and VisualsBitmaps and ImagesThe image CommandBitmap ImagesThe bitmap AttributePhoto ImagesThe Text Insert CursorThe Mouse Cursor
42. Fonts and Text Attributes
Naming a FontNamed FontsSystem FontsUnicode FontsX Font NamesFont Failures before Tk 8.0Font MetricsThe font CommandText AttributesLayoutSelection AttributesGridding, Resizing, and GeometryA Font Selection Application
43. Send
The send CommandSend and X AuthorityThe Sender ScriptCommunicating ProcessesRemote eval through Sockets
44. Window Managers and Window Information
The wm CommandToplevel Size, Placement, and DecorationIconsApplication Session StateMiscellaneous Window Manager OperationsThe winfo CommandSending Commands between ApplicationsWidget Family RelationshipsWidget SizeWidget LocationVirtual Root WindowAtoms and IDsColormaps and VisualsThe tk Command
45. Managing User Preferences
App-Defaults FilesDefining PreferencesThe Preferences User InterfaceManaging the Preferences FileTracing Changes to Preference VariablesImproving the Package
46. A User Interface to Bindings
A Pair of Listboxes Working TogetherThe Editing InterfaceSaving and Loading Bindings
VI. C Programming
47. C Programming and Tcl
Basic ConceptsGetting StartedC Command Procedures and Data ObjectsSWIGTcl InitializationCalling Out to Tcl ScriptsUsing the Tcl C LibraryCreating a Loadable PackageThe load CommandThe Package Initialization ProcedureUsing Tcl_PkgProvideA C Command ProcedureThe String Command InterfaceResult Codes from Command ProceduresManaging the String ResultThe Tcl_Obj Command InterfaceManaging Tcl_Obj Reference CountsModifying Tcl_Obj ValuesPitfalls of Shared Tcl_Obj ValuesThe blob Command ExampleCreating and Destroying Hash TablesTcl_Alloc, ckalloc, and mallocParsing Arguments and Tcl_GetIndexFromObjCreating and Removing Elements from a Hash TableBuilding a ListKeeping References to Tcl_Obj ValuesUsing Tcl_Preserve and Tcl_Release to Guard DataCONST in the Tcl 8.4 APIsStrings and InternationalizationThe DString InterfaceCharacter Set ConversionsTcl_Main and Tcl_AppInitTk_MainThe Event LoopInvoking Scripts from CVariations on Tcl_EvalBypassing Tcl_Eval
48. Compiling Tcl and Extensions
Standard Directory StructureThe Source DistributionThe Installation Directory StructureBuilding Tcl from SourceConfigure and AutoconfStandard Configure FlagsInstallationUsing Stub LibrariesUsing autoconfThe tcl.m4 FileMakefile TemplatesThe Sample Extensionconfigure.inMakefile.inStandard Header FilesUsing the Sample Extension
49. Writing a Tk Widget in C
Initializing the ExtensionThe Widget Data StructureThe Widget Class CommandThe Widget Instance CommandConfiguring and Reconfiguring AttributesSpecifying Widget AttributesDisplaying the ClockThe Window Event ProcedureFinal Cleanup
50. C Library Overview
An Overview of the Tcl C LibraryApplication InitializationCreating and Deleting InterpretersCreating and Deleting CommandsDynamic Loading and PackagesManaging the Result StringMemory AllocationListsCommand ParsingCommand PipelinesTracing the Actions of the Tcl InterpreterEvaluating Tcl CommandsReporting Script ErrorsManipulating Tcl VariablesEvaluating ExpressionsConverting NumbersTcl ObjectsPrimitive Object TypesString Object TypesByteArrays for Binary DataDynamic StringsCharacter Set EncodingsAssocData for per Interpreter Data StructuresHash TablesOption ProcessingRegular Expressions and String MatchingEvent Loop ImplementationFile HandlersTimer EventsIdle CallbacksInput/OutputI/O Channel DriversManipulating File NamesExamining the File SystemVirtual File System ImplementationsThread SupportWorking with SignalsExit HandlersMacintoshPanicMiscellaneousAn Overview of the Tk C LibraryMain Programs and Command-Line ArgumentsCreating WindowsApplication Name for SendConfiguring WindowsCommand OptionsWindow CoordinatesWindow Stacking OrderWindow InformationConfiguring Widget AttributesThe Selection and ClipboardEvent Loop InterfaceHandling Window EventsEvent BindingsKeyboard GrabHandling Graphic Protocol ErrorsUsing the Resource DatabaseManaging BitmapsCreating New Image TypesUsing an Image in a WidgetPhoto Image TypesCanvas Object SupportGeometry ManagementString Identifiers (UIDS)Colors, Colormaps, and Visuals3D BordersMouse CursorsFonts and Text DisplayGraphics ContextsAllocate a PixmapScreen MeasurementsRelief StyleText Anchor PositionsLine Cap StylesLine Join StylesDashed LinesText Justification StylesAtomsX Resource ID ManagementWindows Application Handles
VII. Changes
51. Tcl 7.4/Tk 4.0
wishObsolete FeaturesThe cget OperationInput Focus HighlightBindingsScrollbar Interfacepack infoFocusThe send CommandInternal Button PaddingRadiobutton ValueEntry WidgetMenusListboxesNo geometry AttributeText WidgetColor AttributesColor Allocation and tk colormodelCanvas scrollincrementThe SelectionThe bell Command
52. Tcl 7.5/Tk 4.1
Cross-Platform ScriptsFile Name ManipulationNewline TranslationsThe tcl_platform VariableThe console CommandThe clock CommandThe load CommandThe package CommandMultiple foreach loop variablesEvent Loop Moves from Tk to TclNetwork Socketsinfo hostnameThe fconfigure CommandMultiple Interpreters and Safe-TclThe grid Geometry ManagerThe Text WidgetThe Entry Widget
53. Tcl 7.6/Tk 4.2
More file OperationsVirtual EventsStandard DialogsNew grid Geometry ManagerMacintosh unsupported1 Command
54. Tcl/Tk 8.0
The Tcl CompilerCompile-Time ErrorsBinary String SupportNamespacesSafe-TclNew lsorttcl_precision VariableYear 2000 ConventionHttp PackageSerial Line I/OPlatform-Independent FontsThe tk scaling CommandApplication EmbeddingNative Menus and MenubarsCDE Border WidthNative Buttons and ScrollbarsImages in Text WidgetsNo Errors from destroygrid rowconfigureThe Patch Releasesfconfigure -errortcl_platform(debug)tcl_findLibraryauto_mkindex_oldWindows Keysyms for Start and Menu KeysThe MouseWheel EventTransparent Fill on Canvas Textsafe::loadTk
55. Tcl/Tk 8.1
Unicode and Internationalizationfconfigure -encodingThe encoding CommandThe msgcat PackageUTF-8 and Unicode C APIThread SafetyThe testthread CommandAdvanced Regular ExpressionsNew String CommandsThe DDE ExtensionMiscellaneousSerial Line I/Otcl_platform(user)
56. Tcl/Tk 8.2
The Trf PatchFaster String OperationsEmpty Array NamesBrowser Plugin CompatibilityFiner Control of Windows Serial Port MonitoringRegular Expression Expanded Syntax Option
57. Tcl/Tk 8.3
New File Manipulation Commands and OptionsNew glob OptionsRegular Expression Command EnhancementsDirect Return of scan MatchesRemoving Duplicate List Elements with lsortDeleting Elements from an ArrayEnhanced clock FeaturesSupport for Delayed Package Loading in pkg_mkIndexThe Img PatchThe Dash PatchCanvas ImprovementsHidden TextPointer WarpingEntry Widget ValidationOther New Tk FeaturesListbox EnhancementsNew Directory Chooser DialogWindow Manager Interactions with Toplevel WindowsSupport Added for Windows System CursorsMousewheel Support for Listbox and Text Widgets on UnixNew Quadruple Event ModifierX Input Methods (XIM)The Patch ReleasesDetection of Entry Validation TypeMacintosh File Selection Dialog EnhancementState Attributes for Label WidgetsSupport for Windows IconsNew Reference Pages
58. Tcl/Tk 8.4
64-Bit Support64-Bit Arithmetic64-Bit Value Conversions64-Bit Filesystem SupportNative Word Size DetectionAdditional Filesystem Features and CommandsVirtual FilesystemsNew file Subcommands and glob OptionsNew and Enhanced List CommandsArray Searching and StatisticsEnhanced Support for Serial CommunicationsNew String Comparison OperatorsCommand TracingAdditional Introspection CommandsOther Tcl ChangesUnsetting Nonexistent VariablesDirect Return of Substituted String with regsubIncreased Time Resolution on WindowsBug Fixed in fcopy to Respect Channel EncodingsNew Tk WidgetsText Widget Undo Mechanism and Other EnhancementsNew pack and grid FeaturesAsymmetric PaddingUniform Rows and Columns in gridDisplaying Both Text and an Image in a WidgetNew Button Relief AttributesControlling the State of Entries and ListboxesMore Window Manager InteractionOther Tk ChangesMouse Button Repeat ControlBetter Support for Image TransparencySelecting Multiple Files with tk_getOpenFileFixed-Width Button Support on Windows SystemsEasier Access to Clipboard ContentsDetermining if an Image is UsedNew Events and Substitutions for Window ManagersCaret Management for Improved XIM/IME SupportNew bell Option to Prevent Resetting Screen SaversGenerating Postscript for Embedded Widgets
59. About The CD-ROM
Technical Support

Content preview from Practical Programming in Tcl and Tk, Fourth Edition

Chapter 35. The Listbox Widget

The listbox provides a scrollable list of text lines. The listbox supports selections of one or more lines.

Listbox widgets display a set of text lines in a scrollable display. The basic text unit is a line. There are operations to insert, select, and delete lines, but there are no operations to modify the characters in a line. As such, the listbox is suitable for displaying a set of choices, such as in a file selection dialog. By default a user can select one item from a listbox, but you can select multiple items by setting the selection mode attribute.

Using Listboxes

Manipulating Listbox Contents

The lines in a listbox are indexed from zero. The keyword index end addresses the last line. Other indices are described ...

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