Added plugins/markers.lua

Resolves #27

2 files changed, 104 insertions, 0 deletions

diff --git a/README.md b/README.md
index f5f095f..141864d 100644
--- a/README.md
+++ b/README.md
@@ -43,6 +43,7 @@ Plugin | Description
 [`lineguide`](plugins/lineguide.lua?raw=1) | Displays a line-guide at the line limit offset *([screenshot](https://user-images.githubusercontent.com/3920290/81476159-2cf70000-9208-11ea-928b-9dae3884c477.png))*
 [`linter`](https://github.com/drmargarido/linters)* | Linters for multiple languages
 [`macmodkeys`](plugins/macmodkeys.lua?raw=1) | Remaps mac modkeys `command/option` to `ctrl/alt`
+[`markers`](plugins/markers.lua?raw=1) | Add markers to docs and jump between them quickly *([screenshot](https://user-images.githubusercontent.com/3920290/82252149-5faaa200-9946-11ea-9199-bea2efb7ee23.png))*
 [`openfilelocation`](plugins/openfilelocation.lua?raw=1) | Opens the parent directory of the current file in the file manager
 [`openselected`](plugins/openselected.lua?raw=1) | Opens the selected filename or url
 [`selectionhighlight`](plugins/selectionhighlight.lua?raw=1) | Highlights regions of code that match the current selection *([screenshot](https://user-images.githubusercontent.com/3920290/80710883-5f597c80-8ae7-11ea-97f0-76dfacc08439.png))*
diff --git a/plugins/markers.lua b/plugins/markers.lua
new file mode 100644
index 0000000..6e397d7
--- /dev/null
+++ b/plugins/markers.lua
@@ -0,0 +1,103 @@
+-- Markers plugin for lite text editor

+-- original implementation by Petri Häkkinen

+

+local core = require "core"

+local command = require "core.command"

+local keymap = require "core.keymap"

+local style = require "core.style"

+local DocView = require "core.docview"

+local Doc = require "core.doc"

+

+local cache = {}  -- this table contains subtables for each document, each subtable is a set of line numbers

+setmetatable(cache, {

+  __mode = "k",

+  __index = function(t, k)

+    t[k] = {}

+    return t[k]

+  end,

+})

+

+

+local function shift_lines(doc, at, diff)

+  if diff == 0 then return end

+  local t = {}

+  for line in pairs(cache[doc]) do

+    line = line >= at and line + diff or line

+    t[line] = true

+  end

+  cache[doc] = t

+end

+

+

+local raw_insert = Doc.raw_insert

+

+function Doc:raw_insert(line, col, text, ...)

+  raw_insert(self, line, col, text, ...)

+  local line_count = 0

+  for _ in text:gmatch("\n") do

+    line_count = line_count + 1

+  end

+  shift_lines(self, line, line_count)

+end

+

+

+local raw_remove = Doc.raw_remove

+

+function Doc:raw_remove(line1, col1, line2, col2, ...)

+  raw_remove(self, line1, col1, line2, col2, ...)

+  shift_lines(self, line2, line1 - line2)

+end

+

+

+local draw_line_gutter = DocView.draw_line_gutter

+

+function DocView:draw_line_gutter(idx, x, y)

+  if cache[self.doc] and cache[self.doc][idx] then

+    local h = self:get_line_height()

+    renderer.draw_rect(x, y, style.padding.x * 0.4, h, style.selection)

+  end

+  draw_line_gutter(self, idx, x, y)

+end

+

+

+command.add("core.docview", {

+  ["markers:toggle-marker"] = function()

+    local doc = core.active_view.doc

+    local line = doc:get_selection()

+    local markers = cache[doc]

+

+    if markers[line] then

+      markers[line] = nil

+    else

+      markers[line] = true

+    end

+  end,

+

+  ["markers:go-to-next-marker"] = function()

+    local doc = core.active_view.doc

+    local line = doc:get_selection()

+    local markers = cache[doc]

+

+    local first_marker = math.huge

+    local next_marker = math.huge

+    for l, _ in pairs(markers) do

+      if l > line and l < next_marker then

+        next_marker = l

+      end

+      first_marker = math.min(first_marker, l)

+    end

+    if next_marker == math.huge then

+      next_marker = first_marker

+    end

+    if next_marker ~= math.huge then

+      doc:set_selection(next_marker, 1)

+      core.active_view:scroll_to_line(next_marker, true)

+    end

+  end,

+})

+

+

+keymap.add {

+  ["ctrl+f2"] = "markers:toggle-marker",

+  ["f2"] = "markers:go-to-next-marker",

+}