feat(revamp): add zsh and neovim configs, add an install script and a dependencies list

config/zsh/.zprezto/modules/helper/init.zsh

@@ -0,0 +1,56 @@
+#
+# Defines helper functions.
+#
+# Authors:
+#   Sorin Ionescu <sorin.ionescu@gmail.com>
+#
+
+# Checks if a file can be autoloaded by trying to load it in a subshell.
+function is-autoloadable {
+  ( unfunction $1 ; autoload -U +X $1 ) &> /dev/null
+}
+
+# Checks if a name is a command, function, or alias.
+function is-callable {
+  (( $+commands[$1] || $+functions[$1] || $+aliases[$1] || $+builtins[$1] ))
+}
+
+# Checks a boolean variable for "true".
+# Case insensitive: "1", "y", "yes", "t", "true", "o", and "on".
+function is-true {
+  [[ -n "$1" && "$1" == (1|[Yy]([Ee][Ss]|)|[Tt]([Rr][Uu][Ee]|)|[Oo]([Nn]|)) ]]
+}
+
+# Prints the first non-empty string in the arguments array.
+function coalesce {
+  for arg in $argv; do
+    print "$arg"
+    return 0
+  done
+  return 1
+}
+
+# Checks if running on macOS Darwin.
+function is-darwin {
+  [[ "$OSTYPE" == darwin* ]]
+}
+
+# Checks if running on Linux.
+function is-linux {
+  [[ "$OSTYPE" == linux* ]]
+}
+
+# Checks if running on BSD.
+function is-bsd {
+  [[ "$OSTYPE" == *bsd* ]]
+}
+
+# Checks if running on Cygwin (Windows).
+function is-cygwin {
+  [[ "$OSTYPE" == cygwin* ]]
+}
+
+# Checks if running on termux (Android).
+function is-termux {
+  [[ "$OSTYPE" == linux-android ]]
+}