text_change.md
In rswipl: Embed 'SWI'-'Prolog'

class text_change {#class-text_change}

Record of a single edit to a text_buffer: the range that was replaced and the text that replaced it. text_change objects are the payload of the text_buffer<-changes chain and let editor, fragment and view follow the buffer's edit history.

Positions are 0-based and use UTF-16 code units to match the LSP/DOM conventions other parts of xpce talk to.

@see class text_buffer @see class fragment @see class editor

text_change<-start_line: int 0-based line where the change starts.
text_change<-start_position: int 0-based position on <-start_line, counted in UTF-16 units.
text_change<-end_line: int 0-based line where the change ends.
text_change<-end_position: int 0-based position on <-end_line, counted in UTF-16 units.
text_change<-length: int Length of the replaced region, in UTF-16 units.
text_change<-replacement: string* Text used to replace the region (@nil for a pure deletion).

text_change->initialise: start_line=int, start_position=int, end_line=[int], end_position=[int], length=[int], replacement=[string*] Build a change record from its range and replacement text. end_line/end_position default to start; length defaults to 0.

text_change<-size: -> int Approximate size of this change in bytes (its memory footprint). Used by text_buffer when bounding the size of the undo/redo history.