Add rainbowparen plugin

2 files changed, 59 insertions, 0 deletions

diff --git a/README.md b/README.md
index 502e1ed..0836c06 100644
--- a/README.md
+++ b/README.md
@@ -73,6 +73,7 @@ Plugin | Description
 [`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
 [`projectmanager`](plugins/projectmanager.lua?raw=1) | Save projects and load/reload them quickly
+[`rainbowparen`](plugins/rainbowparen.lua?raw=1) | Show nesting of parentheses with rainbow colours
 [`scale`](plugins/scale.lua?raw=1) | Provides support for dynamically adjusting the scale of the code font / UI (`ctrl+-`, `ctrl+=`)
 [`scalestatus`](plugins/scalestatus.lua?raw=1) | Displays current scale (zoom) in status view (depends on scale plugin)
 [`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/rainbowparen.lua b/plugins/rainbowparen.lua
new file mode 100644
index 0000000..b2689f0
--- /dev/null
+++ b/plugins/rainbowparen.lua
@@ -0,0 +1,58 @@
+local tokenizer = require "core.tokenizer"
+local style = require "core.style"
+local common = require "core.common"
+
+local tokenize = tokenizer.tokenize
+local closers = {
+  ["("] = ")",
+  ["["] = "]",
+  ["{"] = "}"
+}
+local function parenstyle(parenstack)
+  return "paren" .. ((#parenstack % 5) + 1)
+end
+function tokenizer.tokenize(syntax, text, state)
+  state = state or {}
+  local res, istate = tokenize(syntax, text, state.istate)
+  local parenstack = state.parenstack or ""
+  local newres = {}
+  -- split parens out
+  -- the stock tokenizer can't do this because it merges identical adjacent tokens
+  for i, type, text in tokenizer.each_token(res) do
+    if type == "normal" or type == "symbol" then
+      for normtext1, paren, normtext2 in text:gmatch("([^%(%[{}%]%)]*)([%(%[{}%]%)]?)([^%(%[{}%]%)]*)") do
+        if #normtext1 > 0 then
+          table.insert(newres, type)
+          table.insert(newres, normtext1)
+        end
+        if #paren > 0 then
+          if paren == parenstack:sub(-1) then -- expected closer
+            parenstack = parenstack:sub(1, -2)
+            table.insert(newres, parenstyle(parenstack))
+          elseif closers[paren] then -- opener
+            table.insert(newres, parenstyle(parenstack))
+            parenstack = parenstack .. closers[paren]
+          else -- unexpected closer
+            table.insert(newres, "paren_unbalanced")
+          end
+          table.insert(newres, paren)
+        end
+        if #normtext2 > 0 then
+          table.insert(newres, type)
+          table.insert(newres, normtext2)
+        end
+      end
+    else
+      table.insert(newres, type)
+      table.insert(newres, text)
+    end
+  end
+  return newres, { parenstack = parenstack, istate = istate }
+end
+
+style.syntax.paren_unbalanced = style.syntax.paren_unbalanced or { common.color "#DC0408" }
+style.syntax.paren1  =  style.syntax.paren1 or { common.color "#FC6F71"}
+style.syntax.paren2  =  style.syntax.paren2 or { common.color "#fcb053"}
+style.syntax.paren3  =  style.syntax.paren3 or { common.color "#fcd476"}
+style.syntax.paren4  =  style.syntax.paren4 or { common.color "#52dab2"}
+style.syntax.paren5  =  style.syntax.paren5 or { common.color "#5a98cf"}