hanfix.zsh

#!/usr/bin/env zsh
#
# hanfix.zsh — fix commands that were typed with the Korean (2-beolsik)
# keyboard layout switched on by mistake, e.g.:
#
#   $ ㅣㄴ -미ㅗ
#   -> ls -alh
#
# It works by reversing the standard 2-beolsik key mapping: every Hangul
# syllable is decomposed into its jamo (초성/중성/종성), and each jamo is
# mapped back to the Latin key that produces it. Anything that isn't
# Hangul (already-correct English, digits, symbols, spaces, filenames
# typed in Korean on purpose, etc.) is left completely untouched, so
# mixed input is handled fine.
#
# USAGE
#   As a one-off converter/runner:
#       ./hanfix.zsh 'ㅣㄴ -미ㅗ'
#
#   For automatic correction of "command not found" errors, source this
#   file from your .zshrc:
#       source /path/to/hanfix.zsh
#   After that, mistyped Hangul commands are retried automatically.

emulate -L zsh

# ---------------------------------------------------------------------
# 2-beolsik keymap tables
# ---------------------------------------------------------------------

# 19 initial consonants (초성), in Unicode decomposition order
typeset -ga _CHO=(r R s e E f a q Q t T d w W c z x v g)

# 21 vowels (중성), in Unicode decomposition order. Compound vowels
# (ㅘㅙㅚㅝㅞㅟㅢ) are just two keystrokes typed back to back.
typeset -ga _JUNG=(k o i O j p u P h hk ho hl y n nj np nl b m ml l)

# 28 final consonants (종성); index 1 = "no final consonant"
typeset -ga _JONG=(
  ""  r   R   rt  s   sw  sg  e   f   fr
  fa  fq  ft  fx  fv  fg  a   q   qt  t
  T   d   w   c   z   x   v   g
)

# Standalone compatibility jamo (U+3131-U+3163), for jamo that never got
# combined into a full syllable, e.g. a lone ㄴ or ㅣ.
typeset -ga _JAMO=(
  r R rt s sw sg e E f fr fa fq ft fx fv fg a q Q qt t T d w W c z x v g
  k o i O j p u P h hk ho hl y n nj np nl b m ml l
)

# ---------------------------------------------------------------------
# qwerty_from_hangul <string>
#   Prints <string> with every Hangul character replaced by the QWERTY
#   keystrokes that would have produced it on a 2-beolsik layout.
# ---------------------------------------------------------------------
qwerty_from_hangul() {
  emulate -L zsh
  local input="$1" out="" ch
  local -i cp cho jung jong idx

  for ch in "${(@s::)input}"; do
    cp=$(( #ch ))  # codepoint of this single character

    if (( cp >= 0xAC00 && cp <= 0xD7A3 )); then
      # Composed syllable (가-힣): decompose into 초성/중성/종성
      idx=$(( cp - 0xAC00 ))
      jong=$(( idx % 28 ))
      idx=$(( idx / 28 ))
      jung=$(( idx % 21 ))
      cho=$(( idx / 21 ))
      out+="${_CHO[cho+1]}${_JUNG[jung+1]}${_JONG[jong+1]}"
    elif (( cp >= 0x3131 && cp <= 0x3163 )); then
      # Standalone jamo, not (yet) part of a composed syllable
      out+="${_JAMO[cp-0x3131+1]}"
    else
      # Not Hangul at all -- leave mixed-in input exactly as typed
      out+="$ch"
    fi
  done

  print -r -- "$out"
}

# ---------------------------------------------------------------------
# Optional: auto-retry unknown commands after converting them.
# Add `source /path/to/hanfix.zsh` to your .zshrc to enable this.
# ---------------------------------------------------------------------
command_not_found_handler() {
  local original="$*" converted
  converted="$(qwerty_from_hangul "$original")"

  if [[ -n "$converted" && "$converted" != "$original" ]]; then
    print -u2 "zsh: command not found: $1 -- retrying as: $converted"
    eval "$converted"
    return $?
  fi

  print -u2 "zsh: command not found: $1"
  return 127
}

# ---------------------------------------------------------------------
# Direct execution mode: `./hanfix.zsh 'ㅣㄴ -미ㅗ'` converts and runs it.
# When this file is `source`d instead, this block is skipped and only
# the functions above (plus command_not_found_handler) get defined.
# ---------------------------------------------------------------------
if [[ "$ZSH_EVAL_CONTEXT" == "toplevel" ]]; then
  if (( $# == 0 )); then
    print -u2 "usage: $0 <mistyped command>"
    exit 1
  fi
  typeset converted
  converted="$(qwerty_from_hangul "$*")"
  print -r -- "-> $converted"
  eval "$converted"
  exit $?
fi