feat: add auto link

DocGen4/Output/DocString.lean

@@ -9,6 +9,8 @@ namespace Output
 
 open Xml Parser Lean Parsec
 
+instance : Inhabited Element := ⟨"", Std.RBMap.empty, #[]⟩
+
 def manyDocument : Parsec (Array Element) := many (prolog *> element <* many Misc) <* eof
 
 partial def elementToPlainText : Xml.Element → String
@@ -28,13 +30,43 @@ def textToIdAttribute (s : String) : String :=
   |>.toLower
   |>.replace " " "-"
 
-def extendRelativeLink (link : String) (root : String) : String := 
-  -- HACK: better way to detect absolute links
-  if link.startsWith "http" then
-    link
-  else root ++ link
+def possibleNameToLink (s : String) : HtmlM (Option String) := do
+  let res ← getResult
+  let name := s.splitOn "." |>.foldl (λ acc part => Name.mkStr acc part) Name.anonymous
+  if res.name2ModIdx.contains name then
+     declNameToLink name
+  else
+    match (← getCurrentName) with
+    | some currentName =>
+      match (res.moduleInfo.find! currentName).members.find? (·.getName.toString.endsWith s) with
+      | some info => 
+        declNameToLink info.getName
+      | _ => pure none
+    | _ => pure none
 
-partial def addAttributes : Element → HtmlM Element
+def extendRelativeLink (s : String)  : HtmlM String := do
+  -- for relative doc links
+  if s.startsWith "#" then
+    if let some link ← possibleNameToLink (s.drop 1) then
+      pure link
+    else
+      pure s
+  -- for absolute and relative urls
+  else if s.startsWith "http" then
+    pure s
+  else pure ((←getRoot) ++ s)
+
+def possibleNameToAnchor (s : String) : HtmlM Content := do
+  let link? ← possibleNameToLink s
+  match link? with
+  | some link => 
+    let res ← getResult
+    let attributes := Std.RBMap.empty.insert "href" link
+    pure $ Content.Element $ Element.Element "a" attributes #[Content.Character s]
+  | none => pure $ Content.Character s
+
+partial def modifyElement (element : Element) (linkCode : Bool := true) : HtmlM Element :=
+  match element with
   | el@(Element.Element name attrs contents) => do
     -- add id and class to <h_></h_>
     if name = "h1" ∨ name = "h2" ∨ name = "h3" ∨ name = "h4" ∨ name = "h5" ∨ name = "h6" then
@@ -48,21 +80,32 @@ partial def addAttributes : Element → HtmlM Element
         |>.insert "class" "markdown-heading"
       let newContents := (← 
         contents.mapM (λ c => match c with
-      | Content.Element e => (addAttributes e).map (Content.Element)
+        | Content.Element e => (modifyElement e).map (Content.Element)
         | _ => pure c))
+        |>.push (Content.Character " ")
         |>.push (Content.Element anchor)
       pure ⟨ name, newAttrs, newContents⟩ 
     -- extend relative href for <a></a>
     else if name = "a" then
       let root ← getRoot
-    let newAttrs := match attrs.find? "href" with
-    | some href => attrs.insert "href" (extendRelativeLink href root)
-    | none => attrs
+      let newAttrs ← match (attrs.find? "href").map (extendRelativeLink) with
+      | some href => href.map (attrs.insert "href")
+      | none => pure attrs
       pure ⟨ name, newAttrs, contents⟩
+    -- auto link for inline <code></code>
+    else if name = "code" then
+      let mut newContents := #[]
+      for c in contents do
+        match c with
+        | Content.Character s =>
+          newContents := newContents ++ (← s.splitOn.mapM possibleNameToAnchor)
+        | _ => newContents := newContents.push c
+      pure ⟨ name, attrs, newContents⟩
     -- recursively modify
     else
       let newContents ← contents.mapM λ c => match c with
-      | Content.Element e => (addAttributes e).map Content.Element
+        -- disable auto link for code blocks
+        | Content.Element e => (modifyElement e (name ≠ "pre")).map Content.Element
         | _ => pure c
       pure ⟨ name, attrs, newContents ⟩ 
 
@@ -71,7 +114,7 @@ def docStringToHtml (s : String) : HtmlM (Array Html) := do
   match manyDocument rendered.mkIterator with
   | Parsec.ParseResult.success _ res => 
     res.mapM λ x => do
-      pure (Html.text $ toString (← addAttributes x))
+      pure (Html.text $ toString (← modifyElement x))
   | _ => pure #[Html.text rendered]
 
 end Output