class TermBuf::LineBuffer

• TermBuf::LineBuffer
• Reference
• Object

Overview

Editable text and a cursor, in grapheme clusters.

A cluster is what a cursor moves over and what occupies a cell, so it is what this counts in. Every index here is a cluster index, from zero to #size, and the cursor sits between clusters rather than on one. Nothing in here knows about terminals, drawing, or keys; Editor binds keys to it and Field draws it.

Widths come from a Unicode::WidthPolicy, which has to be the one the terminal was measured with or the column this reports is not the column the cursor lands in.

Defined in:

Constant Summary

DEFAULT_WORD = ->(cluster : String) do char = cluster[0]? if char else return false end char.alphanumeric? || (char == '_') end

Alphanumerics and the underscore, which is what readline means by a word.

NEWLINE = "\n"

Constructors

• .new(text : String = "", policy : Unicode::WidthPolicy = Unicode::WidthPolicy::DEFAULT)

Instance Method Summary

• #[](index : Int32) : String | Nil

  The cluster at index, or nil past either end.

• #anchor : Int32 | Nil

  Where a selection started, or nil when nothing is selected.

• #clear : Nil

  Empties it.

• #collapse : Nil

  Drops the selection, leaving the cursor where it is.

• #column : Int32

  Cells between the start of the cursor's line and the cursor.

• #cursor : Int32

  Where the next cluster goes, between zero and #size.

• #delete(range : Range(Int32, Int32)) : String

  Removes range and puts the cursor where it started.

• #delete_backward : Nil

  Removes the cluster before the cursor, or the selection if there is one.

• #delete_forward : Nil

  Removes the cluster after the cursor, or the selection if there is one.

• #delete_selection : Bool

  Removes what is selected.

• #empty? : Bool

  Whether there is nothing to edit.

• #insert(text : String) : Nil

  Inserts text at the cursor, replacing the selection if there is one.

• #insert(char : Char) : Nil

  Inserts text at the cursor, replacing the selection if there is one.

• #kill_to_end : Nil

  Removes from the cursor to the end of the line, keeping it for #yank.

• #kill_to_start : Nil

  Removes from the start of the line to the cursor, keeping it for #yank.

• #kill_word_backward : Nil

  Removes the word before the cursor, keeping it for #yank.

• #kill_word_forward : Nil

  Removes the word after the cursor, keeping it for #yank.

• #killed : String

  What the last kill took, which #yank puts back.

• #line_end : Int32

  End of the line the cursor is on, before the break.

• #line_index : Int32

  Which line the cursor is on, counting from zero.

• #line_start : Int32

  Start of the line the cursor is on.

• #lines : Array(String)

  The text split on its line breaks.

• #move_end : Nil

  To the end of the line the cursor is on.

• #move_home : Nil

  To the start of the line the cursor is on.

• #move_left : Nil

  One cluster left.

• #move_right : Nil

  One cluster right.

• #move_to(index : Int32) : Nil

  Moves the cursor to index, clamped, and drops any selection.

• #move_word_left : Nil

  Back over one word, and the space before it.

• #move_word_right : Nil

  Forward to the end of the next word.

• #policy : Unicode::WidthPolicy

  How clusters are measured, which has to be the policy the terminal was measured with or the column reported here is not the one the cursor lands in.

• #replace(text : String) : Nil

  Throws away everything and starts again with text, cursor at the end.

• #select_all : Nil

  Selects everything, leaving the cursor at the end.

• #select_to(index : Int32) : Nil

  Moves the cursor to index keeping the anchor where it is, which is what a shift-modified motion does.

• #selected? : Bool

  Whether anything is selected.

• #selected_text : String

  What is selected, or an empty string when nothing is.

• #selection : Range(Int32, Int32) | Nil

  The selected clusters, or nil when nothing is selected.

• #size : Int32

  Clusters, not characters and not bytes.

• #slice(range : Range(Int32, Int32)) : String

  The text of a range of clusters.

• #text : String

  Everything, as one string.

• #to_s(io : IO) : Nil

  Appends a short String representation of this object which includes its class name and its object address.

• #transpose : Nil

  Swaps the two clusters around the cursor, which is what Ctrl+T does.

• #width : Int32

  Cells the whole text takes, ignoring line breaks.

• #width_at(index : Int32) : Int32

  Cells the cluster at index takes.

• #width_between(from : Int32, to : Int32) : Int32

  Cells between two cluster indices.

• #word : Proc(String, Bool)

  What counts as part of a word, for the motions and deletions that move by one.

• #word=(word : Proc(String, Bool))

  What counts as part of a word, for the motions and deletions that move by one.

• #word_left : Int32

  Where the cursor would land moving one word left: back over anything that is not a word, then back over the word.

• #word_right : Int32

  Where the cursor would land moving one word left: back over anything that is not a word, then back over the word.

• #yank : Nil

  Puts back what the last kill took.

Constructor Detail

Instance Method Detail

class Person
  def initialize(@name : String, @age : Int32)
  end
end

Person.new("John", 32).to_s # => #<Person:0x10a199f20>