Define functions, KBDs for lf

Defines functions for creating, deleting, renaming files.
Defines functions for encrypting/decrypting files.
Defines functions for archiving/unarchiving files.
Adds TODOs for wishlist items.
Adds `help` function to view `lf` documentation.

TODO: write generic explanation of desire to share KBDs between Emacs, Vim,
other programs that I can link to in documentation to avoid repeating myself.

configs/shared/misc/.config/lf/lfrc

@@ -1 +1,151 @@
-map D delete
+# It might be possible to attempt to share KBDs between `lf` and `dired`.
+# Currently shared KBDs with `dired`:
+#   - D: delete file
+#   - R: rename file
+#   - +: create directory
+#   - c: create file
+#
+# The following command prefixes are used by lf (taken from the docs):
+#
+#    :  read (default)  builtin/custom command
+#    $  shell           shell command
+#    %  shell-pipe      shell command running with the ui
+#    !  shell-wait      shell command waiting for key press
+#    &  shell-async     shell command running asynchronously
+#    /  search          search file in current directory
+#    ?  search-back     search file in the reverse order
+
+# TODO: move most of these commands to function.zsh and call those functions
+# herein. Especially the `archive` and `extract` functions.
+#
+# TODO: consider integrations with `xdg-open` and configuring filetypes to
+# behave in expected "dwim" ways.
+#
+# TODO: learn more about the terms "archive", "compress", "decompress",
+# "expand", "extract", etc. See if a larger abstraction can be created on top
+# without sacrificing too much nuance. This might be the case of "serialize",
+# "deserialize", "pickle", "unpickle", "marshal", "unmarshal", "encode",
+# "decode" -- in which case, a broader abstraction would be nice to decrease the
+# surface area of the vocabulary.
+#
+# TODO: find a way to visualize all of the bound or unbound KBDs.
+#
+# TODO: support polymorphic way encrypt/decrypt a file or directory.
+#
+# TODO: support "toggle" for encryption/decryption that detects which function
+# to run based on the extension.
+#
+# TODO: support "toggle" for archive/unarchive that detects which function to
+# run based on the extension.
+
+# Arguably the most import function herein
+cmd help $lf -doc | less
+
+# delete a file, dir
+map D delete
+
+cmd rename %{{
+    # Renames files, dirs.
+    set -f
+    if [ -e "$1" ]; then
+      printf 'file exists'
+    else
+      mv "$f" "$1"
+    fi
+}}
+map R push :rename<space>
+
+cmd mkdir %{{
+    mkdir -p "$1"
+}}
+map + push :mkdir<space>
+
+cmd touch %{{
+    # Create a file
+    touch "$1"
+}}
+map c push :touch<space>
+
+cmd encrypt_file %{{
+  # Encrypts the file and deletes the cleartext version.
+  # Run `decrypt_file` to return the file to its cleartext version.
+  printf "recipient: "
+  read recipient
+  gpg --encrypt --recipient "$recipient" "$f" && rm "$f"
+}}
+
+cmd decrypt_file %{{
+  # Decrypts a file that was encrypted with `encrypt_file`.
+  # Assumes encrypted files have the .gpg extension and decrypted files omit the
+  # .gpg extension.
+  # Deletes the original .gpg file when finished.
+
+  # check if file exists without .gpg extension
+  if [ -e "${f%.gpg}" ]; then
+    printf "${f%.gpg} exists. Consider deleting or renaming it. Aborting..."
+  else
+    gpg --decrypt "$f" >"${f%.gpg}" 2>/dev/null && rm "$f"
+  fi
+}}
+
+cmd archive %{{
+    # Generic function for archiving directories.
+    # TODO: support selections of multiple files.
+    set -f
+    printf "Which type of archive would you like to create? (tar,tar.gz,zip) "
+    read answer
+    case $answer in
+         tar.gz) tar -czf "$f.tar.gz" "$(basename $f)"; rm -rf "$f";;
+         tar)    tar -cf "$f.tar" "$(basename $f)"; rm -rf "$f";;
+         zip)    zip -r "$f.zip" "$(basename $f)"; rm -rf "$f";;
+         *)      printf "\"$1\" is not a support archive. Aborting..."
+    esac
+}}
+
+cmd unarchive %{{
+    # Generic function for extracting archived directories.
+    # Assumes directories were archived with the `archive`.
+    set -f
+    case $f in
+         *.tar.gz) tar -xzvf $f; rm "$f";;
+         *.tar)    tar -xvf  $f; rm "$f";;
+         *.zip)    unzip "$f"; rm "$f";;
+         # TODO: grab extension from $f and display it in `printf` call.
+         *)        printf "Unsupported archive type. Aborting..."
+    esac
+}}
+
+cmd tar %{{
+    # tars a directory
+    set -f
+    printf "gzip? (y,n) "
+    read answer
+    case $answer in
+         y) tar -czf "$f.tar.gz" "$(basename $f)"; rm -rf "$f";;
+         n) tar -cf  "$f.tar"    "$(basename $f)"; rm -rf "$f";;
+         *) printf "\"$answer\" is not a supported answer. Aborting...";;
+    esac
+}}
+
+cmd untar %{{
+    # untars a directory tar'd with `tar`.
+    set -f
+    case $f in
+         *.tar.gz) tar -xzvf $f; rm "$f";;
+         *.tar)    tar -xvf  $f; rm "$f";;
+    esac
+}}
+
+cmd zip %{{
+    # zip a directory
+    set -f
+    zip -r "$f.zip" "$(basename $f)"
+    rm -rf "$f"
+}}
+
+cmd unzip %{{
+    # unzip a directory
+    set -f
+    unzip "$f"
+    rm "$f"
+}}