zsh: fix aliases/functions such that they can refer to eachother

hosts/common/programs/zsh/default.nix

@@ -180,8 +180,29 @@ in
 
       HISTORY_IGNORE='(sane-shutdown *|sane-reboot *|rm *|nixos-rebuild.* switch|switch)'
 
-      # user-facing helpers.
-      # could be aliases, but then they wouldn't be able to call into eachother.
+      ### aliases
+      # aliases can be defined in any order, regardless of how they reference eachother.
+      # but they must be defined before any functions which use them.
+      #
+      # ls helpers (eza is a nicer `ls`)
+      # l: list directory, one entry per line
+      alias l="eza --time-style=long-iso --bytes --oneline"
+      # la: like `ls -a`
+      alias la="eza --time-style=long-iso --bytes --oneline --all"
+      # lal: like `ls -al`
+      alias lal="eza --time-style=long-iso --bytes --long --all"
+      # ll: like `ls -l`
+      alias ll="eza --time-style=long-iso --bytes --long"
+      # lla: like `ls -al`
+      alias lla="eza --time-style=long-iso --bytes --long --all"
+
+      alias ls="eza --time-style=long-iso --bytes"
+      # escape to use the original (coreutils) `ls`
+      alias _ls="env ls"
+
+      ### functions
+      # N.B. functions must be defined _after_ any aliases they reference;
+      # alias expansion appears to happen at definition time, not call time.
       function c() {
         # list a dir after entering it
         cd "$@"
@@ -196,35 +217,6 @@ in
         chmod u+w "$1"
       }
 
-      # ls helpers (eza is a nicer `ls`)
-      # l: list directory, one entry per line
-      function l() {
-        eza --time-style=long-iso --bytes --oneline "$@"
-      }
-      # la: like `ls -a`
-      function la() {
-        eza --time-style=long-iso --bytes --oneline --all "$@"
-      }
-      # lal: like `ls -al`
-      function lal() {
-        eza --time-style=long-iso --bytes --long --all "$@"
-      }
-      # ll: like `ls -l`
-      function ll() {
-        eza --time-style=long-iso --bytes --long "$@"
-      }
-      # lla: like `ls -al`
-      function lla() {
-        eza --time-style=long-iso --bytes --long --all "$@"
-      }
-      function ls() {
-        eza --time-style=long-iso --bytes "$@"
-      }
-      # escape to use the original (coreutils) `ls`
-      function _ls() {
-        env ls "$@"
-      }
-
       function nd() {
         # enter a directory, creating it if necessary
         mkdir -p "$1"