Module: Tuile::Keys

Defined in:: lib/tuile/keys.rb

Overview

Constants for keys returned by Keys.getkey and helpers for reading them from stdin. The constants are the raw escape sequences emitted by the terminal; see en.wikipedia.org/wiki/ANSI_escape_code for the encoding.

Constant Summary collapse

DOWN_ARROW = Returns: (String)

"\e[B"

UP_ARROW = Returns: (String)

"\e[A"

DOWN_ARROWS = Returns: (Array<String>)

[DOWN_ARROW, "j"].freeze

UP_ARROWS = Returns: (Array<String>)

[UP_ARROW, "k"].freeze

LEFT_ARROW = Returns: (String)

"\e[D"

RIGHT_ARROW = Returns: (String)

"\e[C"

CTRL_LEFT_ARROW = Returns: (String)

"\e[1;5D"

CTRL_RIGHT_ARROW = Returns: (String)

"\e[1;5C"

ESC = Returns: (String)

"\e"

HOME = Returns: (String)

"\e[H"

END_ = Returns: (String)

"\e[F"

HOMES = Home-key sequences. xterm-style (‘HOME`) is the modern default, but the Linux console, rxvt, and tmux/screen in their default configuration emit the VT220-style `e[1~` instead. Components that handle Home should match against this array so users see consistent behavior regardless of which sequence their terminal emits. Returns: (Array<String>)

[HOME, "\e[1~"].freeze

ENDS_ = End-key sequences. See HOMES for why two are recognized. Returns: (Array<String>)

[END_, "\e[4~"].freeze

PAGE_UP = Returns: (String)

"\e[5~"

PAGE_DOWN = Returns: (String)

"\e[6~"

BACKSPACE = Returns: (String)

""

DELETE = Returns: (String)

"\e[3~"

CTRL_H = Returns: (String)

"\b"

BACKSPACES = Returns: (Array<String>)

[BACKSPACE, CTRL_H].freeze

CTRL_U = Returns: (String)

""

CTRL_D = Returns: (String)

""

ENTER = Returns: (String)

"
"

TAB = Returns: (String)

"\t"

SHIFT_TAB = The terminal sequence emitted by Shift+Tab in xterm-style terminals (CSI Z). Used by Screen for reverse focus traversal. Returns: (String)

"\e[Z"

Class Method Summary collapse

.getkey ⇒ String

Grabs a key from stdin and returns it.

Class Method Details

.getkey ⇒ `String`

Grabs a key from stdin and returns it. Blocks until the key is obtained. Reads a full ESC key sequence; see constants above for some values returned by this function.

Returns:

(String) —

key, such as DOWN_ARROW.

# File 'lib/tuile/keys.rb', line 69

def self.getkey
  char = $stdin.getch
  return char unless char == Keys::ESC

  # Escape sequence. Try to read more data.
  begin
    # Read 6 chars: mouse events are e.g. `\e[Mxyz`
    char += $stdin.read_nonblock(6)
  rescue IO::EAGAINWaitReadable
    # The "ESC" key pressed => only the \e char is emitted.
  end
  char
end