Allow creation of nested directories (#254)

* allow nested directories to be created

* fix / be turned into //

* refactor error handling

* refactor path splitting and mkdir calls

If a path exists it will now return immediately.

* fix typo

* remove possible trailing empty string

* fix bugs with path check

data/core/commands/files.lua

@@ -1,12 +1,39 @@
 local core = require "core"
 local command = require "core.command"
 
+local function mkdirp(path)
+  local segments = {}
+  local pos = 1
+  while true do
+    local s, e = string.find(path, "[/\\]+", pos)
+    if not s then break end
+    table.insert(segments, string.sub(str, pos, s - 1))
+    pos = e + 1
+  end
+  table.insert(segments, string.sub(str, pos))
+  if segments[#segments] == '' then
+    table.remove(segments)
+  end
+
+  for i = 1, #segments do
+    local p = table.concat(segments, PATHSEP, 1, i)
+    local stat = system.get_file_info(p)
+    if stat and stat.type == "file" then
+      return nil, "path exists", p
+    end
+    local success, err = system.mkdir(p)
+    if not success then
+      return nil, err, p
+    end
+  end
+end
+
 command.add(nil, {
   ["files:create-directory"] = function()
     core.command_view:enter("New directory name", function(text)
-      local success, err = system.mkdir(text)
+      local success, err, path = mkdirp(text)
       if not success then
-        core.error("cannot create directory %q: %s", text, err)
+        core.error("cannot create directory %q: %s", path, err)
       end
     end)
   end,