Squashed 'mut/vis/vis-editorconfig/' content from commit d2e5f6f

git-subtree-dir: mut/vis/vis-editorconfig
git-subtree-split: d2e5f6f911ce03d17985a2a5e554d81263807181

1 files changed, 208 insertions, 0 deletions

diff --git a/edconf.lua b/edconf.lua
new file mode 100644
index 0000000..7c92f4d
--- /dev/null
+++ b/edconf.lua
@@ -0,0 +1,208 @@
+require "vis"
+local ec = require "editorconfig"
+local M = {}
+
+-- Simple wrapper
+local function vis_set(option, value)
+  if type(value) == "boolean" then
+    if value then
+      value = "yes"
+    else
+      value = "no"
+    end
+  end
+
+  vis:command("set " .. option .. " " .. value)
+end
+
+local 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
+
+local 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
+M.hooks_enabled = false
+vis:option_register("edconfhooks", "bool", function(value)
+  M.hooks_enabled = value
+end, "Enable optional pre-save-hooks for certain editorconfig settings")
+
+local function insert_final_newline(file)
+  -- Technically speaking, this is a pre-save-hook as well and could
+  -- therefore respect edconf_hooks_enabled. Since this function runs
+  -- blazingly fast and scales with a complexity of O(1), however,
+  -- there is no need to disable it.
+  if file.size > 0 and file:content(file.size-1, 1) ~= '\n' then
+    file:insert(file.size, '\n')
+  end
+end
+
+local function strip_final_newline(file)
+  -- In theory, this would have a complexity of O(n) as well and could
+  -- thus be made optional via edconf_hooks_enabled. On the other hand,
+  -- this is probably a very rare edge case, so stripping all trailing
+  -- newline characters is probably safe enough.
+  while file:content(file.size-1, 1) == '\n' do
+    file:delete(file.size-1, 1)
+  end
+end
+
+local function trim_trailing_whitespace(file)
+  if not M.hooks_enabled then return end
+  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
+
+local function enforce_crlf_eol(file)
+  if not M.hooks_enabled then return end
+  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
+
+local function enforce_lf_eol(file)
+  if not M.hooks_enabled then return end
+  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
+
+M.max_line_length = 80     -- This is ugly, but we do want to use
+                           -- single function that we can register
+                           -- or unregister as needed
+local function max_line_length(file)
+  if not M.hooks_enabled then return end
+  local overlong_lines = {}
+  for i=1, #file.lines do
+    if string.len(file.lines[i]) > M.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, M.max_line_length,
+      table.concat(overlong_lines, ",")
+    ))
+  end
+end
+
+local OPTIONS = {
+  indent_style = function (value)
+    vis_set("expandtab", (value == "space"))
+  end,
+
+  indent_size = function (value)
+    if value ~= "tab" then -- tab_width is a synonym anyway
+      vis_set("tabwidth", value)
+    end
+  end,
+
+  tab_width = function (value)
+    vis_set("tabwidth", value)
+  end,
+
+  spelling_language = function (value, file)
+    file.spelling_language = value
+  end,
+
+  insert_final_newline = function (value)
+    -- According to the editorconfig specification, insert_final_newline
+    -- false is supposed to mean stripping the final newline, if present.
+    -- See https://editorconfig-specification.readthedocs.io/#supported-pairs
+    --
+    -- Quote: insert_final_newline Set to true ensure file ends with a
+    -- newline when saving and false to ensure it doesn’t.
+    --
+    set_pre_save(insert_final_newline, tostring(value == "true"))
+    set_pre_save(strip_final_newline, tostring(value == "false"))
+  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
+      M.max_line_length = tonumber(value)
+    end
+    set_pre_save(max_line_length, tostring(value ~= "off"))
+  end,
+
+  -- Not supported by vis
+  --   charset
+  -- Partial support
+  --   end_of_line
+  --   max_line_length
+}
+
+-- Compatible with editorconfig-core-lua v0.3.0
+local function ec_iter(p)
+  local i = 0
+  local props, keys = ec.parse(p)
+  local n = #keys
+  return function ()
+    i = i + 1
+    if i <= n then
+      return keys[i], props[keys[i]]
+    end
+  end
+end
+
+local function ec_set_values(win)
+  if not win or not win.file or not win.file.path then return end
+  for name, value in ec_iter(win.file.path) do
+    if OPTIONS[name] then
+      OPTIONS[name](value, win.file)
+    end
+  end
+end
+
+
+vis:command_register("econfig_parse", function()
+  ec_set_values(vis.win)
+end, "(Re)parse an editorconfig file")
+
+vis.events.subscribe(vis.events.WIN_OPEN, function (win)
+  ec_set_values(win)
+end)
+
+vis.events.subscribe(vis.events.FILE_SAVE_POST, function()
+  ec_set_values(vis.win)
+end)
+
+return M