Add PCRE to support regular expressions

Use regular expressions instead of Lua patterns for find and replace editor commands.

Syntax files can now use regex or Lua patterns as before keeping backward compatibility for plugins.

data/core/doc/search.lua

@@ -15,12 +15,8 @@ local function init_args(doc, line, col, text, opt)
   opt = opt or default_opt
   line, col = doc:sanitize_position(line, col)
 
-  if opt.no_case then
-    if opt.pattern then
-      text = text:gsub("%%?.", pattern_lower)
-    else
-      text = text:lower()
-    end
+  if opt.no_case and not opt.regex then
+    text = text:lower()
   end
 
   return doc, line, col, text, opt
@@ -30,20 +26,32 @@ end
 function search.find(doc, line, col, text, opt)
   doc, line, col, text, opt = init_args(doc, line, col, text, opt)
 
+  local re
+  if opt.regex then
+    re = regex.compile(text, opt.no_case and "i" or "")
+  end
   for line = line, #doc.lines do
     local line_text = doc.lines[line]
-    if opt.no_case then
-      line_text = line_text:lower()
+    if opt.regex then
+      local s, e = re:cmatch(line_text, col)
+      if s then
+        return line, s, line, e
+      end
+      col = 1
+    else
+      if opt.no_case then
+        line_text = line_text:lower()
+      end
+      local s, e = line_text:find(text, col, true)
+      if s then
+        return line, s, line, e + 1
+      end
+      col = 1
     end
-    local s, e = line_text:find(text, col, not opt.pattern)
-    if s then
-      return line, s, line, e + 1
-    end
-    col = 1
   end
 
   if opt.wrap then
-    opt = { no_case = opt.no_case, pattern = opt.pattern }
+    opt = { no_case = opt.no_case, regex = opt.regex }
     return search.find(doc, 1, 1, text, opt)
   end
 end