Adding option to sort case-insensitively

README.md

@@ -13,3 +13,7 @@ Set `"lexical"` to `g:fern#comparator` like
 ```vim
 let g:fern#comparator = "lexical"
 ```
+
+## Options
+
+- `let g:fern#comparator#lexical#case_sensitive`: Whether the listing should be case-sensitive or not (default: `1`)

autoload/fern/comparator/lexical.vim

@@ -1,3 +1,7 @@
+if !exists("g:fern#comparator#lexical#case_sensitive")
+  let g:fern#comparator#lexical#case_sensitive = 1
+endif
+
 function! fern#comparator#lexical#new() abort
   return {
         \ 'compare': funcref('s:compare'),
@@ -10,10 +14,16 @@ function! s:compare(n1, n2) abort
   let l1 = len(k1)
   let l2 = len(k2)
   for index in range(0, min([l1, l2]) - 1)
-    if k1[index] ==# k2[index]
+    let c1 = k1[index]
+    let c2 = k2[index]
+    if !g:fern#comparator#lexical#case_sensitive
+      let c1 = tolower(c1)
+      let c2 = tolower(c2)
+    endif
+    if c1 ==# c2
       continue
     endif
-    return k1[index] > k2[index] ? 1 : -1
+    return c1 > c2 ? 1 : -1
   endfor
   " Shorter first
   let r = s:comp(l1, l2)

doc/fern-comparator-lexical.txt

@@ -22,5 +22,19 @@ Set "lexical" to |g:fern#comparator| like:
 	let g:fern#comparator = "lexical"
 <
 
+
+=============================================================================
+OPTIONS					*fern-comparator-lexical-options*
+
+------------------------------------------------------------------------------
+g:fern#comparator#lexical#case_sensitive          *fern-comparator-lexical-options-case_sensitive*
+
+Set this to 0 to make sorting case-insensitive.
+>
+    let g:fern#comparator#lexical#case_sensitive = 0
+<
+Default: 1 (case-sensitive)
+
+
 =============================================================================
 vim:tw=78:fo=tcq2mM:ts=8:ft=help:norl