dotfiles/zsh/palette.zsh
2019-04-22 13:06:38 +03:00

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#!/usr/bin/env zsh
# This file contains a ZLE widget called 'palette' that lets you select a
# command snippet and fill in its placeholders. It uses "TLDR pages" as the
# snippet database, so the widget will download them on the first invocation.
# Or, you can also create a symlink to a local cache of a "TLDR pages" client,
# e.g. for tealdeer (which is what I use):
#
# ln -sv ~/.cache/tealdeer/tldr-master/pages $ZSH_CACHE_DIR/tldr-pages
#
# Usage:
# 1. press Alt+Shift+P (or Esc+Shift+P)
# 2. select snippet in the fuzzy finder (fzf)
# 3. Press Alt+Shift+P again, this time it'll take you to the first placeholder
# 4. Enter some text
# 5. Repeat steps 3 and 4 until there're no placeholders left
#
# Requirements/Dependencies:
# 1. AWK (any implementation will probably work) for parsing "TLDR pages"
# 2. the FZF fuzzy finder
# 3. Tar (any implementation will probably work) and Curl for downloading
# "TLDR pages"
PALETTE_TLDR_PAGES_DIR="$ZSH_CACHE_DIR/tldr-pages"
# strings which are used to mark placeholders (please don't modify)
PALETTE_PLACEHOLDER_START="{{"
PALETTE_PLACEHOLDER_END="}}"
# a string which is used to separate snippet from its description in the
# fuzzy-finder
PALETTE_SNIPPET_COMMENT=" ## "
# Main function of the widget
_palette_widget() {
# download "TLDR pages" if we don't have them
if [[ ! -d "$PALETTE_TLDR_PAGES_DIR" ]]; then
echo
_palette_download_tldr_pages
echo
fi
# try to fill in a placeholder if there're any, otherwise pick a snippet
if ! _palette_fill_in_placeholder; then
local selected
if selected="$(_palette_parse_tldr_pages | fzf --ansi --cycle --height 50% --reverse)"
then
# paste selected snippet without its description
zle -U "${selected%%$PALETTE_SNIPPET_COMMENT*}"
fi
fi
# immediately redraw
zle redisplay
}
# This function deletes the first placeholder from the buffer and places the
# cursor at the beginning of that placeholder. If there're no placeholders in
# the buffer, it exits with exit code 1.
_palette_fill_in_placeholder() {
# NOTE!!! indexes in ZSH arrays start at one!
local start_index="${BUFFER[(i)$PALETTE_PLACEHOLDER_START]}"
(( start_index == 0 || start_index > ${#BUFFER} )) && return 1
local end_index="${BUFFER[(i)$PALETTE_PLACEHOLDER_END]}"
# the CURSOR variable is zero-based while ZSH arrays are one-based
(( CURSOR = start_index - 1 ))
BUFFER="${BUFFER[1,start_index-1]}${BUFFER[end_index+2,${#BUFFER}]}"
}
# This function parses "TLDR pages" for snippets using AWK. Fortunately, all
# "TLDR pages" files are use the same Markdown-like syntax so they're very easy
# to parse.
_palette_parse_tldr_pages() {
# I chose to use AWK here because it was designed specifically for text
# processing and includes all basic utilities that I need here.
awk '
# when we find a "description" line...
match($0, /^- (.+):$/, match_groups) {
# ...get actual description from it...
description = match_groups[1]
# ...then skip any lines that are not actual commands, while saving RegEx
# match groups...
while (!match($0, /^`(.+)`$/, match_groups)) getline
# ...after that we can get the command...
command = match_groups[1]
# ...and finally, we print command and description, separated by
# PALETTE_SNIPPET_COMMENT, and with some colors!
printf "%s\x1b[90m'"$PALETTE_SNIPPET_COMMENT"'%s\x1b[0m\n", command, description
}
' "$PALETTE_TLDR_PAGES_DIR"/**/*.md
}
# This function downloads the "TLDR pages"
_palette_download_tldr_pages() {
mkdir -pv "$PALETTE_TLDR_PAGES_DIR"
echo "Downloading tldr pages..."
if curl -Lf https://github.com/tldr-pages/tldr/archive/master.tar.gz |
tar -C "$PALETTE_TLDR_PAGES_DIR" --gzip --strip-components 2 --extract tldr-master/pages
then
echo "Done!"
fi
}
# finally, bind the widget to Alt+Shift+P (or Esc+Shift+P)
zle -N _palette_widget
bindkey "^[P" _palette_widget