Add autoclose plugin to handle autoclose for brackets, quotes etc...

The plugin adds an option `autoclose` to configure whether or not you
would like quotes, brackets etc... to be automatically closed. The
option is enabled by default.

Closes #176

cmd/micro/micro.go

@@ -248,6 +248,7 @@ func main() {
 	L.SetGlobal("BindKey", luar.New(L, BindKey))
 	L.SetGlobal("MakeCommand", luar.New(L, MakeCommand))
 	L.SetGlobal("CurView", luar.New(L, CurView))
+	L.SetGlobal("IsWordChar", luar.New(L, IsWordChar))
 
 	L.SetGlobal("JobStart", luar.New(L, JobStart))
 	L.SetGlobal("JobSend", luar.New(L, JobSend))

cmd/micro/plugin.go

@@ -14,6 +14,7 @@ var loadedPlugins []string
 var preInstalledPlugins = []string{
 	"go",
 	"linter",
+	"autoclose",
 }
 
 // Call calls the lua function 'function'

runtime/help/help.md

@@ -227,6 +227,10 @@ Default plugin options:
 
 	default value: `on`
 
+* `autoclose`: Automatically close `{}` `()` `[]` `""` `''`. Provided by the autoclose plugin
+
+    default value: `on`
+
 * `goimports`: Run goimports on save. Provided by the `go` plugin.
 
 	default value: `off`

runtime/plugins/autoclose/autoclose.lua

@@ -0,0 +1,78 @@
+getmetatable('').__index = function(str,i) return string.sub(str,i,i) end
+
+if GetOption("autoclose") == nil then
+    AddOption("autoclose", true)
+end
+
+local autoclosePairs = {"\"\"", "''", "()", "{}", "[]"}
+local autoNewlinePairs = {"()", "{}", "[]"}
+
+function onRune(r)
+    if not GetOption("autoclose") then
+        return
+    end
+
+    local v = CurView()
+    for i = 1, #autoclosePairs do
+        if r == autoclosePairs[i][2] then
+            local curLine = v.Buf:Line(v.Cursor.Y)
+
+            if curLine[v.Cursor.X+1] == autoclosePairs[i][2] then
+                v:Backspace()
+                v:CursorRight()
+                break
+            end
+
+            if v.Cursor.X > 1 and (IsWordChar(curLine[v.Cursor.X-1]) or curLine[v.Cursor.X-1] == autoclosePairs[i][1]) then
+                break
+            end
+        end
+        if r == autoclosePairs[i][1] then
+            local curLine = v.Buf:Line(v.Cursor.Y)
+
+            if v.Cursor.X == #curLine or not IsWordChar(curLine[v.Cursor.X+1]) then
+                -- the '-' here is to derefence the pointer to v.Cursor.Loc which is automatically made
+                -- when converting go structs to lua
+                -- It needs to be dereferenced because the function expects a non pointer struct
+                v.Buf:Insert(-v.Cursor.Loc, autoclosePairs[i][2])
+                break
+            end
+        end
+    end
+end
+
+function onInsertEnter()
+    if not GetOption("autoclose") then
+        return
+    end
+
+    local v = CurView()
+    local curLine = v.Buf:Line(v.Cursor.Y)
+    local lastLine = v.Buf:Line(v.Cursor.Y-1)
+    local curRune = lastLine[#lastLine]
+    local nextRune = curLine[1]
+
+    for i = 1, #autoNewlinePairs do
+        if curRune == autoNewlinePairs[i][1] then
+            if nextRune == autoNewlinePairs[i][2] then
+                v:InsertTab()
+                v.Buf:Insert(-v.Cursor.Loc, "\n")
+            end
+        end
+    end
+end
+
+function onBackspace()
+    if not GetOption("autoclose") then
+        return
+    end
+
+    local v = CurView()
+
+    for i = 1, #autoclosePairs do
+        local curLine = v.Buf:Line(v.Cursor.Y)
+        if curLine[v.Cursor.X+1] == autoclosePairs[i][2] then
+            v:Delete()
+        end
+    end
+end