add bash ceru tool

2026-01-07 21:40:40 +10:00 · 2026-01-07 21:40:40 +10:00 · b366820ddf
commit b366820ddf
parent aef76779ed
4 changed files with 283 additions and 0 deletions
--- a/ceru/libceru.sh
+++ b/ceru/libceru.sh
@ -0,0 +1,105 @@
+#!/usr/bin/env bash
+
+# libceru relies on the script that sources
+# it to set the following environment variables:
+#     CMD_NAME USAGE
+set -u 
+
+# ======== INTERNAL STATE ========
+SUBCMDS="$PWD/subcmds" # XXX: TODO: don't hardcode as relative
+CMD_ABS="$SUBCMDS" # (initial value) CMD_ABS stores the current cmd's absolute path
+CMD_MAJ="$THIS"    # (initial value) CMD_MAJ stores the current cmd's parent's name
+CMD_MIN=""         # (initial value) CMD_MIN stores the current cmd's name
+# ======== INTERNAL STATE ========
+
+# ANSI Coloring
+BLACK='\033[30m'
+RED='\033[31m'
+GREEN='\033[32m'
+YELLOW='\033[33m'
+BLUE='\033[34m'
+MAGENTA='\033[35m'
+CYAN='\033[36m'
+WHITE='\033[37m'
+DEFCOL='\033[39m' # default colour
+
+# ANSI Styling
+RESET='\033[0m'
+BOLD='\033[1m'
+DIM='\033[2m'
+ITALIC='\033[3m'
+UNDERLINE='\033[4m'
+BLINKSLOW='\033[5m'
+BLINKFAST='\033[6m'
+REVERSE='\033[7m'
+INVISIBLE='\033[8m'
+
+# Error Messages
+function perr            { echo -e "${BOLD}${RED}error:${RESET} $@\nTry ${BOLD}${GREEN}'--help'${RESET} for more information." >&2; }
+function perr-usage      { echo -e "$USAGE" >&2; }
+function perr-badflag    { perr "unrecognised flag ${BOLD}${MAGENTA}'$1'${RESET}"; }
+function perr-noflagval  { perr "flag ${BOLD}${MAGENTA}'$1'${RESET} requires ${BOLD}${MAGENTA}${2}${RESET} argument(s), but only ${BOLD}${MAGENTA}${3}${RESET} were given"; }
+function perr-badarg     { perr "unrecognised arg ${BOLD}${MAGENTA}'$1'${RESET}"; }
+function perr-noarg      { perr "required argument ${BOLD}${MAGENTA}'$1'${RESET} is missing"; }
+# Failures
+function throw           { echo -e "${@:2}" >&2; if [[ "$1" -ge 0 ]]; then exit "$1"; fi; }
+function throw-usage     { throw "$1" "$(perr-usage 2>&1)"; }
+function throw-badflag   { throw "$1" "$(perr-badflag "${@:2}" 2>&1)"; }
+function throw-noflagval { throw "$1" "$(perr-noflagval "${@:2}" 2>&1)"; }
+function throw-badarg    { throw "$1" "$(perr-badarg "${@:2}" 2>&1)"; }
+function throw-noarg     { throw "$1" "$(perr-noarg "${@:2}" 2>&1)"; }
+# Parsing/Validation
+function required { [[ -n "$1" ]] || throw-noarg 1 "${@:2}"; }
+
+# Other
+function confirm-action {
+  local CHAR
+  while :; do
+    echo -e "$1"
+    read -n1 CHAR
+    case $CHAR in
+      [yY])
+        return 0 ;;
+      [nN])
+        return 1 ;;
+    esac
+  done
+}
+function confirm { confirm-action ":: Proceed? [Y/n]  "; }
+
+function confirm-file-overwrite {
+  echo -e "${BOLD}${UNDERLINE}${BLINKFAST}${RED}WARNING!${RESET} ${YELLOW}The following files will be overwritten:${RESET}"
+  local ARG=""
+  for ARG in "$@"; do
+    echo -e "${BOLD}	• ${GREEN}${ARG}${RESET}"
+  done 
+	confirm
+}
+
+# ====== Core ======
+function run-subcmd {
+  # if CMD_MIN is empty, then CMD_MAJ is the root cmd (ie ceru)
+  # and hence CMD_MAJ shouldn't yet be overridden
+  if [[ ! "$CMD_MIN" = "" ]]; then
+    CMD_MAJ="$CMD_MIN" # swapsies!
+  fi
+  # we shift here so $@ is passed correctly when we `source "$TARGET"`
+  CMD_MIN="$1"; shift
+
+  # ensure the current command can take subcommands
+  if [[ -f "$CMD_ABS" ]]; then
+    # XXX: INTERNAL ERROR
+    throw 2 "Subcommand \"$CMD_MIN\" cannot exist, as $CMD_MAJ has no subcommands!"
+  fi
+
+  CMD_ABS="$CMD_ABS/$CMD_MIN"
+
+  # attempt to find the script corresponding to CMD_ABS
+  TARGET="$CMD_ABS"
+  if [[ -d "$CMD_ABS" ]]; then
+    TARGET="$TARGET/default.sh"
+  elif [[ ! -f "$CMD_ABS" ]]; then
+      throw 1 "Command \"$CMD_MAJ\" does not provide subcommand \"$CMD_MIN\"!"
+  fi
+  source "$TARGET"
+}