fix partial, systemctl manpage

lib/manpage.ml

@@ -698,6 +698,115 @@ let parse_mdoc_lines lines =
   in
   { entries = List.rev entries; subcommands = []; positionals; description = "" }
 
+(* --- COMMANDS section subcommand extraction --- *)
+
+(* Extract subcommands from COMMANDS/COMMAND sections.
+   These use .PP + bold name + .RS/.RE blocks, e.g.:
+     .PP
+     \fBstart\fR \fIUNIT\fR...
+     .RS 4
+     Start (activate) one or more units.
+     .RE  *)
+let extract_commands_section lines =
+  let classified = List.map classify_line lines in
+  let rec collect_until_next_sh lines acc =
+    match lines with
+    | [] -> List.rev acc
+    | Macro ("SH", _) :: _ -> List.rev acc
+    | line :: rest -> collect_until_next_sh rest (line :: acc)
+  in
+  let is_commands_section name =
+    let s = String.uppercase_ascii (String.trim name) in
+    s = "COMMANDS" || s = "COMMAND"
+  in
+  let rec find_commands acc = function
+    | [] -> List.rev acc
+    | Macro ("SH", args) :: rest when is_commands_section args ->
+      find_commands (collect_until_next_sh rest [] :: acc) rest
+    | _ :: rest -> find_commands acc rest
+  in
+  let sections = find_commands [] classified in
+  List.concat sections
+
+(* Extract subcommand name from a bold groff text like
+   "\fBlist\-units\fR [\fIPATTERN\fR...]" → "list-units" *)
+let extract_bold_command_name text =
+  let s = String.trim text in
+  (* Look for \fB...\fR at the start *)
+  if String.length s >= 4
+     && s.[0] = '\\' && s.[1] = 'f' && s.[2] = 'B' then
+    let start = 3 in
+    let end_marker = "\\fR" in
+    match String.split_on_char '\\' (String.sub s start (String.length s - start)) with
+    | name_part :: _ ->
+      let name = strip_groff_escapes ("\\fB" ^ name_part ^ end_marker) |> String.trim in
+      (* Must look like a subcommand: lowercase, hyphens, no leading dash *)
+      if String.length name >= 2
+         && name.[0] <> '-'
+         && String.for_all (fun c ->
+              (c >= 'a' && c <= 'z') || (c >= '0' && c <= '9') || c = '-' || c = '_'
+            ) name
+      then Some name
+      else None
+    | [] -> None
+  else
+    (* Try already-stripped text *)
+    let stripped = strip_groff_escapes s in
+    let first_word = match String.split_on_char ' ' stripped with
+      | w :: _ -> w | [] -> "" in
+    if String.length first_word >= 2
+       && first_word.[0] <> '-'
+       && String.for_all (fun c ->
+            (c >= 'a' && c <= 'z') || (c >= '0' && c <= '9') || c = '-' || c = '_'
+          ) first_word
+    then Some first_word
+    else None
+
+let extract_subcommands_from_commands lines =
+  let rec walk lines acc =
+    match lines with
+    | [] -> List.rev acc
+    | Macro ("PP", _) :: rest ->
+      begin match rest with
+        | Text tag :: rest2 ->
+          (* Check if this is a subcommand (bold name, not a flag) *)
+          begin match extract_bold_command_name tag with
+            | Some name ->
+              (* Collect description from .RS/.RE block *)
+              let rec collect_desc lines desc_acc =
+                match lines with
+                | Macro ("RS", _) :: rest3 ->
+                  collect_in_rs rest3 desc_acc
+                | Text s :: rest3 ->
+                  collect_desc rest3 (s :: desc_acc)
+                | _ -> (String.concat " " (List.rev desc_acc), lines)
+              and collect_in_rs lines desc_acc =
+                match lines with
+                | Macro ("RE", _) :: rest3 ->
+                  (String.concat " " (List.rev desc_acc), rest3)
+                | Text s :: rest3 ->
+                  collect_in_rs rest3 (s :: desc_acc)
+                | Macro ("PP", _) :: _ | Macro ("SH", _) :: _ | Macro ("SS", _) :: _ ->
+                  (String.concat " " (List.rev desc_acc), lines)
+                | _ :: rest3 -> collect_in_rs rest3 desc_acc
+                | [] -> (String.concat " " (List.rev desc_acc), [])
+              in
+              let (desc, rest3) = collect_desc rest2 [] in
+              let desc = String.trim desc in
+              (* Take first sentence as description *)
+              let short_desc = match String.split_on_char '.' desc with
+                | first :: _ when String.length first > 0 -> String.trim first
+                | _ -> desc in
+              let sc : subcommand = { name; desc = short_desc } in
+              walk rest3 (sc :: acc)
+            | None -> walk rest2 acc
+          end
+        | _ -> walk rest acc
+      end
+    | _ :: rest -> walk rest acc
+  in
+  walk lines []
+
 (* --- Top-level API --- *)
 
 let parse_manpage_lines lines =
@@ -707,7 +816,9 @@ let parse_manpage_lines lines =
     let options_section = extract_options_section lines in
     let entries = extract_entries options_section in
     let positionals = extract_synopsis_positionals_lines lines in
-    { entries; subcommands = []; positionals; description = "" }
+    let commands_section = extract_commands_section lines in
+    let subcommands = extract_subcommands_from_commands commands_section in
+    { entries; subcommands; positionals; description = "" }
   end
 
 let parse_manpage_string contents =