Implement additional settings as pre-save-hooks

1 files changed, 100 insertions, 3 deletions

diff --git a/edconf.lua b/edconf.lua
index e3fb921..9b5a546 100644
--- a/edconf.lua
+++ b/edconf.lua
@@ -14,6 +14,75 @@ function vis_set(option, value)
   vis:command("set " .. option .. " " .. value)
 end
 
+function set_pre_save(f, value)
+  if value == "true" then
+    vis.events.subscribe(vis.events.FILE_SAVE_PRE, f)
+  else
+    vis.events.unsubscribe(vis.events.FILE_SAVE_PRE, f)
+  end
+end
+
+function set_file_open(f, value)
+  if value == "true" then
+    vis.events.subscribe(vis.events.FILE_OPEN, f)
+  else
+    vis.events.unsubscribe(vis.events.FILE_OPEN, f)
+  end
+end
+
+-- Custom functionality
+function insert_final_newline(file, path)
+  if file:content(file.size-1, file.size) ~= '\n' then
+    file:insert(file.size, '\n')
+  end
+end
+
+function trim_trailing_whitespace(file, path)
+  for i=1, #file.lines do
+    if string.match(file.lines[i], '[ \t]$') then
+      file.lines[i] = string.gsub(file.lines[i], '[ \t]*$', '')
+    end
+  end
+end
+
+function enforce_crlf_eol(file, path)
+  for i=1, #file.lines do
+    if not string.match(file.lines[i], '\r$') then
+      file.lines[i] = string.gsub(file.lines[i], '$', '\r')
+    end
+  end
+end
+
+function enforce_lf_eol(file, path)
+  for i=1, #file.lines do
+    if string.match(file.lines[i], '\r$') then
+      file.lines[i] = string.gsub(file.lines[i], '\r$', '')
+    end
+  end
+end
+
+global_max_line_length = 80     -- This is ugly, but we do want to use
+                                -- single function that we can register
+                                -- or unregister as needed
+function max_line_length(file, path)
+  local overlong_lines = {}
+  for i=1, #file.lines do
+    if string.len(file.lines[i]) > global_max_line_length then
+      table.insert(overlong_lines, i)
+    end
+  end
+  if #overlong_lines > 0 then
+    local lines_are = (function(x)
+        if x>1 then return "lines are" else return "line is" end
+    end)(#overlong_lines)
+    vis:info(string.format(
+      "%d %s longer than %d characters: %s",
+      #overlong_lines, lines_are, global_max_line_length,
+      table.concat(overlong_lines, ",")
+    ))
+  end
+end
+
 OPTIONS = {
   indent_style = function (value)
     vis_set("expandtab", (value == "space"))
@@ -29,11 +98,39 @@ OPTIONS = {
     vis_set("tabwidth", value)
   end,
 
+  insert_final_newline = function (value)
+    set_pre_save(insert_final_newline, value)
+  end,
+
+  trim_trailing_whitespace = function (value)
+    set_pre_save(trim_trailing_whitespace, value)
+  end,
+
+  -- End of line is only partially implemented. While vis does not
+  -- support customized newlines, it does work well enough with crlf
+  -- newlines. Therefore, setting end_of_line=crlf will just ensure
+  -- that there is a cr at the end of each line. Setting end_of_line=lf
+  -- will strip any cr characters at the end of lines. This hopefully
+  -- eases the pain of working with crlf files a little.
+  end_of_line = function (value)
+    set_pre_save(enforce_crlf_eol, tostring(value == "crlf"))
+    set_pre_save(enforce_lf_eol, tostring(value == "lf"))
+  end,
+
+  -- There is probably no straightforward way to enforce a maximum line
+  -- length across different programming languages. If a maximum line
+  -- length is set, we can at least issue a warning, however.
+  max_line_length = function(value)
+    if value ~= "off" then
+      global_max_line_length = tonumber(value)
+    end
+    set_pre_save(max_line_length, tostring(value ~= "off"))
+  end,
+
   -- Not supported by vis
-  --   end_of_line
   --   charset
-  --   trim_trailing_whitespace
-  --   insert_final_newline
+  -- Partial support
+  --   end_of_line
   --   max_line_length
 }