prompt for nix-shell and init.zsh hook for pretzo

init.zsh

@@ -0,0 +1,3 @@
+
+# Source module files.
+source "${0:h}/nix.plugin.zsh" || return 1

nix.plugin.zsh

@@ -1,5 +1,24 @@
 # Nix Install
-# alias ni='nix-env -iA'
+alias ni='nix-env -iA'
 
 # Nix Search
-# alias ns='nix-env -qaP'
+alias ns='nix-env -qaP'
+
+function prompt_nix_shell_precmd {
+  if [[ ${IN_NIX_SHELL} -eq 1 ]] then
+    if [[ -n ${IN_WHICH_NIX_SHELL} ]] then
+      NIX_SHELL_NAME=": ${IN_WHICH_NIX_SHELL}"
+    fi
+    NIX_PROMPT="%F{8}[%F{3}nix-shell${NIX_SHELL_NAME}%F{8}]%f"
+    if [[ $PROMPT != *"$NIX_PROMPT"* ]] then
+      PROMPT="$NIX_PROMPT $PROMPT"
+    fi
+  fi
+}
+
+function prompt_nix_shell_setup {
+  autoload -Uz add-zsh-hook
+  add-zsh-hook precmd prompt_nix_shell_precmd
+}
+
+prompt_nix_shell_setup "$@"