KDE API Reference

Contents

KTextEditor::CodeCompletionModel Class

class KTextEditor::CodeCompletionModel

An item model for providing code completion, and meta information for enhanced presentation. More...

Header: #include <KTextEditor/CodeCompletionModel>
CMake: find_package(KF6 REQUIRED COMPONENTS TextEditor)
target_link_libraries(mytarget PRIVATE KF6::TextEditor)
Inherits: QAbstractItemModel

Public Types

enum Columns { Prefix, Icon, Scope, Name, Arguments, Postfix }
flags CompletionProperties
enum CompletionProperty { NoProperty, FirstProperty, Public, Protected, Private, …, LastProperty }
enum ExtraItemDataRoles { CompletionRole, ScopeIndex, MatchQuality, SetMatchContext, HighlightingMethod, …, LastExtraItemDataRole }
enum HighlightMethod { NoHighlighting, InternalHighlighting, CustomHighlighting }
flags HighlightMethods
enum InvocationType { AutomaticInvocation, UserInvocation, ManualInvocation }

Public Functions

CodeCompletionModel(QObject *parent)
virtual void completionInvoked(KTextEditor::View *view, const KTextEditor::Range &range, KTextEditor::CodeCompletionModel::InvocationType invocationType)
virtual void executeCompletionItem(KTextEditor::View *view, const KTextEditor::Range &word, const QModelIndex &index) const
bool hasGroups() const

Reimplemented Public Functions

virtual int columnCount(const QModelIndex &parent = QModelIndex()) const override
virtual QModelIndex index(int row, int column, const QModelIndex &parent = QModelIndex()) const override
virtual QMap<int, QVariant> itemData(const QModelIndex &index) const override
virtual QModelIndex parent(const QModelIndex &index) const override
virtual int rowCount(const QModelIndex &parent = QModelIndex()) const override

Signals

(since 4.3) void waitForReset()

Detailed Description

Introduction

The CodeCompletionModel is the actual workhorse to provide code completions in a KTextEditor::View. It is meant to be used in conjunction with the View. The CodeCompletionModel is not meant to be used as is. Rather you need to implement a subclass of CodeCompletionModel to actually generate completions appropriate for your type of Document.

Implementing a CodeCompletionModel

The CodeCompletionModel is a QAbstractItemModel, and can be subclassed in the same way. It provides default implementations of several members, however, so in most cases (if your completions are essentially a non-hierarchical, flat list of matches) you will only need to overload few virtual functions.

Implementing a CodeCompletionModel for a flat list

For the simple case of a flat list of completions, you will need to:

  • Implement completionInvoked() to actually generate/update the list of completion matches
  • implement itemData() (or QAbstractItemModel::data()) to return the information that should be displayed for each match.
  • use setRowCount() to reflect the number of matches.

Columns and roles

TODO document the meaning and usage of the columns and roles used by the

Completion Interface

Using the new CodeCompletionModel

To start using your KTextEditor::View Completion Interface.

ControllerInterface to get more control

To have more control over code completion implement CodeCompletionModelControllerInterface in your CodeCompletionModel.

See also KTextEditor::CodeCompletionModelControllerInterface.

Member Type Documentation

enum CodeCompletionModel::Columns

ConstantValueDescription
KTextEditor::CodeCompletionModel::Prefix0 
KTextEditor::CodeCompletionModel::Icon1Icon representing the type of completion. We have a separate icon field so that names remain aligned where only some completions have icons, and so that they can be rearranged by the user.
KTextEditor::CodeCompletionModel::Scope2 
KTextEditor::CodeCompletionModel::Name3 
KTextEditor::CodeCompletionModel::Arguments4 
KTextEditor::CodeCompletionModel::Postfix5 

enum CodeCompletionModel::CompletionProperty
flags CodeCompletionModel::CompletionProperties

ConstantValue
KTextEditor::CodeCompletionModel::NoProperty0x0
KTextEditor::CodeCompletionModel::FirstProperty0x1
KTextEditor::CodeCompletionModel::Public0x1
KTextEditor::CodeCompletionModel::Protected0x2
KTextEditor::CodeCompletionModel::Private0x4
KTextEditor::CodeCompletionModel::Static0x8
KTextEditor::CodeCompletionModel::Const0x10
KTextEditor::CodeCompletionModel::Namespace0x20
KTextEditor::CodeCompletionModel::Class0x40
KTextEditor::CodeCompletionModel::Struct0x80
KTextEditor::CodeCompletionModel::Union0x100
KTextEditor::CodeCompletionModel::Function0x200
KTextEditor::CodeCompletionModel::Variable0x400
KTextEditor::CodeCompletionModel::Enum0x800
KTextEditor::CodeCompletionModel::Template0x1000
KTextEditor::CodeCompletionModel::TypeAlias0x2000
KTextEditor::CodeCompletionModel::Virtual0x4000
KTextEditor::CodeCompletionModel::Override0x8000
KTextEditor::CodeCompletionModel::Inline0x10000
KTextEditor::CodeCompletionModel::Friend0x20000
KTextEditor::CodeCompletionModel::Signal0x40000
KTextEditor::CodeCompletionModel::Slot0x80000
KTextEditor::CodeCompletionModel::LocalScope0x100000
KTextEditor::CodeCompletionModel::NamespaceScope0x200000
KTextEditor::CodeCompletionModel::GlobalScope0x400000
KTextEditor::CodeCompletionModel::LastPropertyGlobalScope

The CompletionProperties type is a typedef for QFlags<CompletionProperty>. It stores an OR combination of CompletionProperty values.

enum CodeCompletionModel::ExtraItemDataRoles

Meta information is passed through extra {Qt::ItemDataRole}s. This information should be returned when requested on the Name column.

ConstantValueDescription
KTextEditor::CodeCompletionModel::CompletionRoleQt::UserRoleThe model should return a set of CompletionProperties.
KTextEditor::CodeCompletionModel::ScopeIndex257The model should return an index to the scope -1 represents no scope. TODO how to sort scope?
KTextEditor::CodeCompletionModel::MatchQuality258If requested, your model should try to determine whether the completion in question is a suitable match for the context (ie. is accessible, exported, + returns the data type required). The returned data should ideally be matched against the argument-hint context set earlier by SetMatchContext. Return an integer value that should be positive if the completion is suitable, and zero if the completion is not suitable. The value should be between 0 an 10, where 10 means perfect match. Return QVariant::Invalid if you are unable to determine this.
KTextEditor::CodeCompletionModel::SetMatchContext259Is requested before MatchQuality(..) is requested. The item on which this is requested is an argument-hint item When this role is requested, the item should be noted, and whenever MatchQuality is requested, it should be computed by matching the item given with MatchQuality into the context chosen by SetMatchContext. Feel free to ignore this, but ideally you should return QVariant::Invalid to make clear that your model does not support this.
KTextEditor::CodeCompletionModel::HighlightingMethod260Define which highlighting method will be used:
  • QVariant::Invalid - allows the editor to choose (usually internal highlighting)
  • QVariant::Integer - highlight as specified by HighlightMethods.
KTextEditor::CodeCompletionModel::CustomHighlight261Allows an item to provide custom highlighting.
Return a QList<QVariant> in the following format (repeat this triplet as many times as required, however each column must be >= the previous, and startColumn != endColumn):
  • int startColumn (where 0 = start of the completion entry)
  • int endColumn (note: not length)
  • QTextFormat attribute (note: attribute may be a KTextEditor::Attribute, as it is a child class) If the attribute is invalid, and the item is an argument-hint, the text will be drawn with a background-color depending on match-quality, or yellow. You can use that to mark the actual arguments that are matched in an argument-hint.
KTextEditor::CodeCompletionModel::InheritanceDepth262Returns the inheritance depth of the completion. For example, a completion which comes from the base class would have depth 0, one from a parent class would have depth 1, one from that class' parent 2, etc. you can use this to symbolize the general distance of a completion-item from a user. It will be used for sorting.
KTextEditor::CodeCompletionModel::IsExpandable263This allows items in the completion-list to be expandable. If a model returns an QVariant bool value that evaluates to true, the completion-widget will draw a handle to expand the item, and will also make that action accessible through keyboard.
KTextEditor::CodeCompletionModel::ExpandingWidget264After a model returned true for a row on IsExpandable, the row may be expanded by the user. When this happens, ExpandingWidget is requested. The model may return two types of values:
  • QWidget*: If the model returns a QVariant of type QWidget*, the code-completion takes over the given widget and embeds it into the completion-list under the completion-item. The widget will be automatically deleted at some point. The completion-widget will use the height of the widget as a hint for its preferred size, but it will resize the widget at will.
  • QString: If the mode returns a QVariant of type QString, it will create a small html-widget showing the given html-code, and embed it into the completion-list under the completion-item.

    Warning: This will not work correctly:

     QWidget* widget;
return QVariant(widget);

    Use the following instead.:

    QVariant v;
v.setValue<QWidget*>(widget);
return v;
KTextEditor::CodeCompletionModel::ItemSelected265Whenever an item is selected, this will be requested from the underlying model. It may be used as a simple notification that the item was selected. Above that, the model may return a QString, which then should then contain html-code. A html-widget will then be displayed as a one- or two-liner under the currently selected item(it will be partially expanded)
KTextEditor::CodeCompletionModel::ArgumentHintDepth266Is this completion-item an argument-hint? The model should return an integral positive number if the item is an argument-hint, and QVariant() or 0 if it is not one. The returned depth-integer is important for sorting and matching.
Example: "otherFunction(function1(function2("
all functions named function2 should have ArgumentHintDepth 1, all functions found for function1 should have ArgumentHintDepth 2, and all functions named otherFunction should have ArgumentHintDepth 3
Later, a completed item may then be matched with the first argument of function2, the return-type of function2 with the first argument-type of function1, and the return-type of function1 with the argument-type of otherFunction.
If the model returns a positive value on this role for a row, the content will be treated specially:
  • It will be shown in a separate argument-hint list
  • It will be sorted by Argument-hint depth
  • Match-qualities will be illustrated by differently highlighting the matched argument if possible The argument-hint list strings will be built from all source-model, with a little special behavior:
    • Prefix - should be all text of the function-signature up to left of the matched argument of the function
    • Name - should be the type and name of the function's matched argument. This part will be highlighted differently depending on the match-quality
    • Suffix - should be all the text of the function-signature behind the matched argument
      Example: You are matching a function with signature "void test(int param1, int param2)", and you are matching the first argument.
      The model should then return:
      Prefix "void test(" Name: "int param1" Suffix: ", int param2)"
      If you don't use the highlighting, matching, etc. you can also return the columns in the usual way.
KTextEditor::CodeCompletionModel::BestMatchesCount267This will be requested for each item to ask whether it should be included in computing a best-matches list. If you return a valid positive integer n here, the n best matches will be listed at top of the completion-list separately.
This is expensive because all items of the whole completion-list will be tested for their matching-quality, with each of the level 1 argument-hints.
For that reason the end-user should be able to disable this feature.
KTextEditor::CodeCompletionModel::AccessibilityNext268The following three enumeration-values are only used on expanded completion-list items that contain an expanding-widget.
You can use them to allow the user to interact with the widget by keyboard.
AccessibilityNext will be requested on an item if it is expanded, contains an expanding-widget, and the user triggers a special navigation short-cut to go to navigate to the next position within the expanding-widget(if applicable).
Return QVariant(true) if the input was used.
KTextEditor::CodeCompletionModel::AccessibilityPrevious269AccessibilityPrevious will be requested on an item if it is expanded, contains an expanding-widget, and the user triggers a special navigation short-cut to go to navigate to the previous position within the expanding-widget(if applicable).
Return QVariant(true) if the input was used.
KTextEditor::CodeCompletionModel::AccessibilityAccept270AccessibilityAccept will be requested on an item if it is expanded, contains an expanding-widget, and the user triggers a special shortcut to trigger the action associated with the position within the expanding-widget the user has navigated to using AccessibilityNext and AccessibilityPrevious.
This should return QVariant(true) if an action was triggered, else QVariant(false) or QVariant().
KTextEditor::CodeCompletionModel::GroupRole271Using this Role, it is possible to greatly optimize the time needed to process very long completion-lists.
In the completion-list, the items are usually ordered by some properties like argument-hint depth, inheritance-depth and attributes. Kate usually has to query the completion-models for these values for each item in the completion-list in order to extract the argument-hints and correctly sort the completion-list. However, with a very long completion-list, only a very small fraction of the items is actually visible.
By using a tree structure you can give the items in a grouped order to kate, so it does not need to look at each item and query data in order to initially show the completion-list.
This is how it works:
  • You create a tree-structure for your items
  • Every inner node of the tree defines one attribute value that all sub-nodes have in common.
    • When the inner node is queried for GroupRole, it should return the "ExtraItemDataRoles" that all sub-nodes have in common
    • When the inner node is then queried for that exact role, it should return that value.
    • No other queries will be done to inner nodes.
  • Every leaf node stands for an actual item in the completion list.
  • The recommended grouping order is: Argument-hint depth, inheritance depth, attributes. This role can also be used to define completely custom groups, bypassing the editors builtin grouping:
    • Return Qt::DisplayRole when GroupRole is requested
    • Return the label text of the group when Qt::DisplayRole
    • Optional: Return an integer sorting-value when InheritanceDepth is requested. This number will be used to determine the order of the groups. The order of the builtin groups is: 1=Best Matches, 100=Local Scope, 200=Public, 300=Protected, 400=Private, 500=Namespace, 600=Global
      You can pick any arbitrary number to position your group relative to these builtin groups.
KTextEditor::CodeCompletionModel::UnimportantItemRole272Return a nonzero value here to enforce sorting the item at the end of the list.
KTextEditor::CodeCompletionModel::LastExtraItemDataRole273 

See also ArgumentHintDepth and ExpandingWidget.

enum CodeCompletionModel::HighlightMethod
flags CodeCompletionModel::HighlightMethods

ConstantValue
KTextEditor::CodeCompletionModel::NoHighlighting0x0
KTextEditor::CodeCompletionModel::InternalHighlighting0x1
KTextEditor::CodeCompletionModel::CustomHighlighting0x2

The HighlightMethods type is a typedef for QFlags<HighlightMethod>. It stores an OR combination of HighlightMethod values.

enum CodeCompletionModel::InvocationType

ConstantValue
KTextEditor::CodeCompletionModel::AutomaticInvocation0
KTextEditor::CodeCompletionModel::UserInvocation1
KTextEditor::CodeCompletionModel::ManualInvocation2

Member Function Documentation

[explicit] CodeCompletionModel::CodeCompletionModel(QObject *parent)

[override virtual] int CodeCompletionModel::columnCount(const QModelIndex &parent = QModelIndex()) const

Reimplements: QAbstractItemModel::columnCount(const QModelIndex &parent) const.

Reimplemented from QAbstractItemModel::columnCount(). The default implementation returns ColumnCount for all indices.

[virtual] void CodeCompletionModel::completionInvoked(KTextEditor::View *view, const KTextEditor::Range &range, KTextEditor::CodeCompletionModel::InvocationType invocationType)

This function is responsible to generating / updating the list of current completions. The default implementation does nothing.

When implementing this function, remember to call setRowCount() (or implement rowCount()), and to generate the appropriate change notifications (for instance by calling QAbstractItemModel::reset()).

view is the view to generate completions for

range is the range of text to generate completions for

invocationType describes how the code completion was triggered

[virtual] void CodeCompletionModel::executeCompletionItem(KTextEditor::View *view, const KTextEditor::Range &word, const QModelIndex &index) const

This function is responsible for inserting a selected completion into the view. The default implementation replaces the text that the completions were based on with the Qt::DisplayRole of the Name column of the given match.

view is the view to insert the completion into

word is the Range that the completions are based on (what the user entered so far)

index identifies the completion match to insert

bool CodeCompletionModel::hasGroups() const

This function returns true if the model needs grouping, otherwise false. The default is false if not changed via setHasGroups().

[override virtual] QModelIndex CodeCompletionModel::index(int row, int column, const QModelIndex &parent = QModelIndex()) const

Reimplements: QAbstractItemModel::index(int row, int column, const QModelIndex &parent) const.

Reimplemented from QAbstractItemModel::index(). The default implementation returns a standard QModelIndex as long as the row and column are valid.

[override virtual] QMap<int, QVariant> CodeCompletionModel::itemData(const QModelIndex &index) const

Reimplements: QAbstractItemModel::itemData(const QModelIndex &index) const.

Reimplemented from QAbstractItemModel::itemData(). The default implementation returns a map with the QAbstractItemModel::data() for all roles that are used by the CodeCompletionInterface. You will need to reimplement either this function or QAbstractItemModel::data() in your CodeCompletionModel.

[override virtual] QModelIndex CodeCompletionModel::parent(const QModelIndex &index) const

Reimplements: QAbstractItemModel::parent(const QModelIndex &index) const.

Reimplemented from QAbstractItemModel::parent(). The default implementation returns an invalid QModelIndex for all items. This is appropriate for non-hierarchical / flat lists of completions.

[override virtual] int CodeCompletionModel::rowCount(const QModelIndex &parent = QModelIndex()) const

Reimplements: QAbstractItemModel::rowCount(const QModelIndex &parent) const.

Reimplemented from QAbstractItemModel::rowCount(). The default implementation returns the value set by setRowCount() for invalid (toplevel) indices, and 0 for all other indices. This is appropriate for non-hierarchical / flat lists of completions

[signal, since 4.3] void CodeCompletionModel::waitForReset()

Emit this if the code-completion for this model was invoked, some time is needed in order to get the data, and the model is reset once the data is available.

This only has an effect if emitted from within completionInvoked(..).

This prevents the code-completion list from showing until this model is reset, so there is no annoying flashing in the user-interface resulting from other models supplying their data earlier.

Note: The implementation may choose to show the completion-list anyway after some timeout

Warning: If you emit this, you _must_ also reset the model at some point, else the code-completion will be completely broken to the user. Consider that there may always be additional completion-models apart from yours.

This function was introduced in 4.3.