forked from Mirrors/bubbletea
279 lines
6.8 KiB
Go
279 lines
6.8 KiB
Go
package tea
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import (
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"errors"
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"fmt"
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"io"
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"unicode/utf8"
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)
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// KeyMsg contains information about a keypress.
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type KeyMsg Key
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// String returns a friendly name for a key.
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func (k *KeyMsg) String() (str string) {
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if k.Alt {
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str += "alt+"
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}
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if k.Type == KeyRune {
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str += string(k.Rune)
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return str
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} else if s, ok := keyNames[int(k.Type)]; ok {
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str += s
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return str
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}
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return ""
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}
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// IsRune returns weather or not the key is a rune.
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func (k *KeyMsg) IsRune() bool {
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return k.Type == KeyRune
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}
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// Key contains information about a keypress.
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type Key struct {
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Type KeyType
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Rune rune
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Alt bool
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}
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// KeyType indicates the key pressed.
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type KeyType int
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// Control keys. I know we could do this with an iota, but the values are very
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// specific, so we set the values explicitly to avoid any confusion.
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//
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// See also:
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// https://en.wikipedia.org/wiki/C0_and_C1_control_codes
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const (
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keyNUL = 0 // null, \0
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keySOH = 1 // start of heading
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keySTX = 2 // start of text
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keyETX = 3 // break, ctrl+c
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keyEOT = 4 // end of transmission
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keyENQ = 5 // enquiry
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keyACK = 6 // acknowledge
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keyBEL = 7 // bell, \a
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keyBS = 8 // backspace
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keyHT = 9 // horizontal tabulation, \t
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keyLF = 10 // line feed, \n
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keyVT = 11 // vertical tabulation \v
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keyFF = 12 // form feed \f
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keyCR = 13 // carriage return, \r
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keySO = 14 // shift out
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keySI = 15 // shift in
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keyDLE = 16 // data link escape
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keyDC1 = 17 // device control one
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keyDC2 = 18 // device control two
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keyDC3 = 19 // device control three
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keyDC4 = 20 // device control four
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keyNAK = 21 // negative acknowledge
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keySYN = 22 // synchronous idle
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keyETB = 23 // end of transmission block
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keyCAN = 24 // cancel
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keyEM = 25 // end of medium
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keySUB = 26 // substitution
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keyESC = 27 // escape, \e
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keyFS = 28 // file separator
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keyGS = 29 // group separator
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keyRS = 30 // record separator
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keyUS = 31 // unit separator
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keySP = 32 // space
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keyDEL = 127 // delete. on most systems this is mapped to backspace, I hear
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)
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// Aliases
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const (
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KeyNull = keyNUL
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KeyBreak = keyETX
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KeyEnter = keyCR
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KeyBackspace = keyBS
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KeyTab = keyHT
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KeySpace = keySP
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KeyEsc = keyESC
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KeyEscape = keyESC
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KeyDelete = keyDEL
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KeyCtrlAt = keyNUL // ctrl+@
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KeyCtrlA = keySOH
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KeyCtrlB = keySTX
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KeyCtrlC = keyETX
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KeyCtrlD = keyEOT
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KeyCtrlE = keyENQ
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KeyCtrlF = keyACK
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KeyCtrlG = keyBEL
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KeyCtrlH = keyBS
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KeyCtrlI = keyHT
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KeyCtrlJ = keyLF
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KeyCtrlK = keyVT
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KeyCtrlL = keyFF
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KeyCtrlM = keyCR
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KeyCtrlN = keySO
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KeyCtrlO = keySI
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KeyCtrlP = keyDLE
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KeyCtrlQ = keyDC1
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KeyCtrlR = keyDC2
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KeyCtrlS = keyDC3
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KeyCtrlT = keyDC4
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KeyCtrlU = keyNAK
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KeyCtrlV = keyETB
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KeyCtrlW = keyETB
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KeyCtrlX = keyCAN
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KeyCtrlY = keyEM
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KeyCtrlZ = keySUB
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KeyCtrlOpenBracket = keyESC // ctrl+[
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KeyCtrlBackslash = keyFS // ctrl+\
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KeyCtrlCloseBracket = keyGS // ctrl+]
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KeyCtrlCaret = keyRS // ctrl+^
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KeyCtrlUnderscore = keyUS // ctrl+_
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KeyCtrlQuestionMark = keyDEL // ctrl+?
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)
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// Other keys we track
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const (
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KeyRune = -(iota + 1)
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KeyUp
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KeyDown
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KeyRight
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KeyLeft
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KeyShiftTab
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KeyHome
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KeyEnd
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KeyPgUp
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KeyPgDown
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)
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// Mapping for control keys to friendly consts
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var keyNames = map[int]string{
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keyNUL: "ctrl+@", // also ctrl+`
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keySOH: "ctrl+a",
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keySTX: "ctrl+b",
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keyETX: "ctrl+c",
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keyEOT: "ctrl+d",
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keyENQ: "ctrl+e",
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keyACK: "ctrl+f",
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keyBEL: "ctrl+g",
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keyBS: "backspace", // also ctrl+h
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keyHT: "tab", // also ctrl+i
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keyLF: "ctrl+j",
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keyVT: "ctrl+k",
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keyFF: "ctrl+l",
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keyCR: "enter",
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keySO: "ctrl+n",
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keySI: "ctrl+o",
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keyDLE: "ctrl+p",
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keyDC1: "ctrl+q",
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keyDC2: "ctrl+r",
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keyDC3: "ctrl+s",
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keyDC4: "ctrl+t",
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keyNAK: "ctrl+u",
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keySYN: "ctrl+v",
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keyETB: "ctrl+w",
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keyCAN: "ctrl+x",
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keyEM: "ctrl+y",
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keySUB: "ctrl+z",
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keyESC: "esc",
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keyFS: "ctrl+\\",
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keyGS: "ctrl+]",
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keyRS: "ctrl+^",
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keyUS: "ctrl+_",
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keySP: "space",
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keyDEL: "delete",
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KeyRune: "rune",
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KeyUp: "up",
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KeyDown: "down",
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KeyRight: "right",
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KeyLeft: "left",
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KeyShiftTab: "shift+tab",
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KeyHome: "home",
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KeyEnd: "end",
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KeyPgUp: "pgup",
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KeyPgDown: "pgdown",
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}
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// Mapping for sequences to consts
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// TODO: should we just move this into the hex table?
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var sequences = map[string]KeyType{
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"\x1b[A": KeyUp,
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"\x1b[B": KeyDown,
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"\x1b[C": KeyRight,
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"\x1b[D": KeyLeft,
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}
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// Mapping for hex codes to consts. Unclear why these won't register as
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// sequences.
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var hexes = map[string]Key{
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"1b5b5a": {Type: KeyShiftTab},
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"1b0d": {Type: KeyEnter, Alt: true},
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"1b7f": {Type: KeyDelete, Alt: true},
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"1b5b48": {Type: KeyHome},
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"1b5b377e": {Type: KeyHome}, // urxvt
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"1b5b313b3348": {Type: KeyHome, Alt: true},
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"1b1b5b377e": {Type: KeyHome, Alt: true}, // ursvt
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"1b5b46": {Type: KeyEnd},
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"1b5b387e": {Type: KeyEnd}, // urxvt
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"1b5b313b3346": {Type: KeyEnd, Alt: true},
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"1b1b5b387e": {Type: KeyEnd, Alt: true}, // urxvt
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"1b5b357e": {Type: KeyPgUp},
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"1b5b353b337e": {Type: KeyPgUp, Alt: true},
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"1b1b5b357e": {Type: KeyPgUp, Alt: true}, // urxvt
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"1b5b367e": {Type: KeyPgDown},
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"1b5b363b337e": {Type: KeyPgDown, Alt: true},
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"1b1b5b367e": {Type: KeyPgDown, Alt: true}, // urxvt
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"1b5b313b3341": {Type: KeyUp, Alt: true},
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"1b5b313b3342": {Type: KeyDown, Alt: true},
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"1b5b313b3343": {Type: KeyRight, Alt: true},
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"1b5b313b3344": {Type: KeyLeft, Alt: true},
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}
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// ReadKey reads keypress input from a TTY and returns a string representation
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// of a key.
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func ReadKey(r io.Reader) (Key, error) {
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var buf [256]byte
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// Read and block
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numBytes, err := r.Read(buf[:])
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if err != nil {
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return Key{}, err
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}
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hex := fmt.Sprintf("%x", buf[:numBytes])
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// Some of these need special handling
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if k, ok := hexes[hex]; ok {
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return k, nil
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}
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// Get unicode value
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char, _ := utf8.DecodeRune(buf[:])
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if char == utf8.RuneError {
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return Key{}, errors.New("could not decode rune")
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}
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// Is it a control character?
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if numBytes == 1 && char <= keyUS || char == keyDEL {
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return Key{Type: KeyType(char)}, nil
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}
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// Is it a special sequence, like an arrow key?
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if k, ok := sequences[string(buf[:numBytes])]; ok {
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return Key{Type: k}, nil
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}
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// Is the alt key pressed? The buffer will be prefixed with an escape
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// sequence if so
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if numBytes > 1 && buf[0] == 0x1b {
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// Now remove the initial escape sequence and re-process to get the
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// character.
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c, _ := utf8.DecodeRune(buf[1:])
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if c == utf8.RuneError {
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return Key{}, errors.New("could not decode rune after removing initial escape")
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}
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return Key{Alt: true, Type: KeyRune, Rune: c}, nil
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}
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// Just a regular, ol' rune
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return Key{Type: KeyRune, Rune: char}, nil
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}
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