def Lean.Meta.Hint.tryThisDiffWidget : Widget.Module

A widget for rendering code action suggestions in error messages. Generally, this widget should not be used directly; instead, use MessageData.hint. Note that this widget is intended only for use within message data; it may not display line breaks properly if rendered as a panel widget.

The props to this widget are of the following form:

{
  "diff": [
    {"type": "unchanged", "text": "h"},
    {"type": "deletion", "text": "ello"},
    {"type": "insertion", "text": "i"}
  ]
}

Note: we cannot add the builtin_widget_module attribute here because that would require importing Lean.Widget.UserWidget, which in turn imports much of Lean.Elab -- the module where we want to be able to use this widget. Instead, we register the attribute post-hoc when we declare the regular "Try This" widget in Lean.Meta.Tactic.TryThis.

structure Lean.Meta.Hint.Suggestionextends Lean.Meta.Tactic.TryThis.Suggestion : Type

A code action suggestion associated with a hint in a message.

Refer to TryThis.Suggestion; this extends that structure with a span? field, allowing a single hint to suggest modifications at different locations. If span? is not specified, then the syntax reference provided to MessageData.hint will be used.

• suggestion : SuggestionText
• preInfo? : Option String
• postInfo? : Option String
• style? : Option SuggestionStyle
• messageData? : Option MessageData
• toCodeActionTitle? : Option (String → String)
• span? : Option Syntax

instance Lean.Meta.Hint.instCoeSuggestionTextSuggestion : Coe Tactic.TryThis.SuggestionText Suggestion

instance Lean.Meta.Hint.instToMessageDataSuggestion : ToMessageData Suggestion

def Lean.Meta.Hint.readableDiff (s s' : String) : Array (Diff.Action × String)

Produces a diff that splits either on characters, tokens, or not at all, depending on the edit distance between the arguments.

Guarantees that all actions in the output will be maximally grouped; that is, instead of returning #[(.insert, "a"), (.insert, "b")], it will return #[(.insert, "ab")].

def Lean.Meta.Hint.readableDiff.splitChars (s : String) : Array Char

def Lean.Meta.Hint.readableDiff.joinEdits {α : Type} (ds : Array (Diff.Action × α)) : Array (Diff.Action × Array α)

def Lean.Meta.Hint.mkSuggestionsMessage (suggestions : Array Suggestion) (ref : Syntax) (codeActionPrefix? : Option String) : CoreM MessageData

Creates message data corresponding to a HintSuggestions collection and adds the corresponding info leaf.

def Lean.MessageData.hint (hint : MessageData) (suggestions : Array Meta.Hint.Suggestion) (ref? : Option Syntax := none) (codeActionPrefix? : Option String := none) : CoreM MessageData

Creates a hint message with associated code action suggestions.

To provide a hint without an associated code action, use MessageData.hint'.

The arguments are as follows:

• hint: the main message of the hint, which precedes its code action suggestions.
• suggestions: the suggestions to display.
• ref?: if specified, the syntax location for the code action suggestions; otherwise, default to the syntax reference in the monadic state. Will be overridden by the span? field on any suggestions that specify it.
• codeActionPrefix?: if specified, text to display in place of "Try this: " in the code action label