diff --git a/DocGen4/Output/Base.lean b/DocGen4/Output/Base.lean
index 60923d2..4aef3b9 100644
--- a/DocGen4/Output/Base.lean
+++ b/DocGen4/Output/Base.lean
@@ -66,10 +66,10 @@ def declNameToLink (name : Name) : HtmlM String := do
   pure $ (←moduleNameToLink module) ++ "#" ++ name.toString
 
 def splitWhitespaces (s : String) : (String × String × String) := Id.run do
-  let front := "".pushn ' ' (s.find (!Char.isWhitespace ·))
+  let front := "".pushn ' ' $ s.offsetOfPos (s.find (!Char.isWhitespace ·))
   let mut s := s.trimLeft
   let back := "".pushn ' ' (s.length - s.offsetOfPos (s.find Char.isWhitespace))
-  s:= s.trimRight
+  s := s.trimRight
   (front, s, back)
 
 partial def infoFormatToHtml (i : CodeWithInfos) : HtmlM (Array Html) := do
diff --git a/DocGen4/Output/DocString.lean b/DocGen4/Output/DocString.lean
index 32fe1af..d729d38 100644
--- a/DocGen4/Output/DocString.lean
+++ b/DocGen4/Output/DocString.lean
@@ -17,7 +17,7 @@ namespace Output
     let c := s.get i
     if p c then
       let i := s.next i
-      splitAroundAux s p i i (c.toString::s.extract b (i-1)::r)
+      splitAroundAux s p i i (c.toString::s.extract b (i-⟨1⟩)::r)
     else
       splitAroundAux s p b (s.next i) r
 
diff --git a/DocGen4/ToHtmlFormat.lean b/DocGen4/ToHtmlFormat.lean
index 64e9b6a..c8f83d1 100644
--- a/DocGen4/ToHtmlFormat.lean
+++ b/DocGen4/ToHtmlFormat.lean
@@ -81,8 +81,8 @@ def jsxText : Parser :=
 @[combinatorFormatter DocGen4.Jsx.jsxText] def jsxText.formatter : Formatter := pure ()
 @[combinatorParenthesizer DocGen4.Jsx.jsxText] def jsxText.parenthesizer : Parenthesizer := pure ()
 
-syntax jsxAttrName := ident <|> strLit
-syntax jsxAttrVal := strLit <|> group("{" term "}")
+syntax jsxAttrName := ident <|> str
+syntax jsxAttrVal := str <|> group("{" term "}")
 syntax jsxSimpleAttr := jsxAttrName "=" jsxAttrVal
 syntax jsxAttrSpread := "[" term "]"
 syntax jsxAttr := jsxSimpleAttr <|> jsxAttrSpread
@@ -103,12 +103,12 @@ def translateAttrs (attrs : Array Syntax) : MacroM Syntax := do
     as ← match attr with
     | `(jsxAttr| $n:jsxAttrName=$v:jsxAttrVal) =>
       let n ← match n with
-        | `(jsxAttrName| $n:strLit) => pure n
+        | `(jsxAttrName| $n:str) => pure n
         | `(jsxAttrName| $n:ident) => pure $ quote (toString n.getId)
         | _ => Macro.throwUnsupported
       let v ← match v with
         | `(jsxAttrVal| {$v}) => pure v
-        | `(jsxAttrVal| $v:strLit) => pure v
+        | `(jsxAttrVal| $v:str) => pure v
         | _ => Macro.throwUnsupported
       `(($as).push ($n, ($v : String)))
     | `(jsxAttr| [$t]) => `($as ++ ($t : Array (String × String)))
diff --git a/lakefile.lean b/lakefile.lean
index d18d59c..d7d73b6 100644
--- a/lakefile.lean
+++ b/lakefile.lean
@@ -19,7 +19,7 @@ package «doc-gen4» {
     },
     {
       name := `lake
-      src := Source.git "https://github.com/leanprover/lake" "9378575b5575f49a185d50130743a190a9be2f82"
+      src := Source.git "https://github.com/leanprover/lake" "d961d8cfaa1c354c10f3fed55b32de85c205f4ab"
     }
   ]
 }
diff --git a/lean-toolchain b/lean-toolchain
index 8e380ba..4b053c2 100644
--- a/lean-toolchain
+++ b/lean-toolchain
@@ -1 +1 @@
-leanprover/lean4:nightly-2022-03-06
+leanprover/lean4:nightly-2022-04-04