jq -> nix

doc/manual/generate-manpage.nix

@@ -0,0 +1,56 @@
+with builtins;
+with import ./utils.nix;
+
+let
+
+  showCommand =
+    { command, section, def }:
+    "${section} Name\n\n"
+    + "`${command}` - ${def.description}\n\n"
+    + "${section} Synopsis\n\n"
+    + showSynopsis { inherit command; args = def.args; }
+    + (if def ? doc
+       then "${section} Description\n\n" + def.doc + "\n\n"
+       else "")
+    + (let s = showFlags def.flags; in
+       if s != ""
+       then "${section} Flags\n\n${s}"
+       else "")
+    + (if def.examples or [] != []
+       then
+         "${section} Examples\n\n"
+         + concatStrings (map ({ description, command }: "${description}\n\n```console\n${command}\n```\n\n") def.examples)
+       else "")
+    + (if def.commands or [] != []
+       then concatStrings (
+         map (name:
+           "# Subcommand `${command} ${name}`\n\n"
+           + showCommand { command = command + " " + name; section = "##"; def = def.commands.${name}; })
+           (attrNames def.commands))
+       else "");
+
+  showFlags = flags:
+    concatStrings
+      (map (longName:
+        let flag = flags.${longName}; in
+        if flag.category or "" != "config"
+        then
+          "  - `--${longName}`"
+          + (if flag ? shortName then " / `${flag.shortName}`" else "")
+          + (if flag ? labels then " " + (concatStringsSep " " (map (s: "*${s}*") flag.labels)) else "")
+          + "  \n"
+          + "    " + flag.description + "\n\n"
+        else "")
+        (attrNames flags));
+
+  showSynopsis =
+    { command, args }:
+    "`${command}` [*flags*...] ${concatStringsSep " "
+      (map (arg: "*${arg.label}*" + (if arg ? arity then "" else "...")) args)}\n\n";
+
+in
+
+command:
+
+"Title: nix\n\n"
++ showCommand { command = "nix"; section = "#"; def = command; }