fennel: extract some common functions into a shareable module

pkgs/anoia/README

@@ -0,0 +1,14 @@
+
+In Terry Pratchett's Discworld novels, Anoi is a minor goddess of Things That Stick In Drawers
+
+> Often, but not uniquely, a ladle, but sometimes a metal spatula or,
+> rarely, a mechanical egg-whisk that nobody in the house admits to
+> ever buying. The desperate mad rattling and cries of ‘How can it
+> close on the damn thing but not open with it? Who bought this? Do we
+> ever use it?’ is as praise unto Anoia. She also eats corkscrews.
+
+This is a library of miscellaneous Fennel code used in Liminix that is
+shared between various scripts but doesn't really fit together. It is
+not a public stable interface - while any Liminix code is welcome to
+use it, it's suject to reshuffle, rearrangement, refactor or rejection
+without notice.

pkgs/anoia/default.nix

@@ -0,0 +1,19 @@
+{
+  fennel
+, stdenv
+, lua
+}:
+let pname =  "anoia";
+in stdenv.mkDerivation {
+  inherit pname;
+  version = "0.1";
+  src = ./.;
+  nativeBuildInputs = [ fennel ];
+  buildPhase = ''
+    fennel --compile init.fnl > init.lua
+  '';
+  installPhase = ''
+    mkdir -p "$out/share/lua/${lua.luaversion}/${pname}"
+    cp *.lua "$out/share/lua/${lua.luaversion}/${pname}"
+  '';
+}

pkgs/anoia/init.fnl

@@ -0,0 +1,16 @@
+(fn merge [table1 table2]
+  (collect [k v (pairs table2) &into table1]
+    k v))
+
+(fn split [sep string]
+  (icollect [v (string.gmatch string (.. "([^" sep "]+)"))]
+    v))
+
+(fn file-exists? [name]
+  (match (io.open name :r)
+    f (do (f:close) true)
+    _ false))
+
+(fn system [s] (assert (os.execute s)))
+
+{ : merge : split : file-exists? : system }