some additions to the plugin API

Those changes were originally used for the snippet plugin which
may not be part of the core.

cmd/micro/eventhandler.go

@@ -1,9 +1,11 @@
 package main
 
 import (
+	"strings"
 	"time"
 
 	dmp "github.com/sergi/go-diff/diffmatchpatch"
+	"github.com/yuin/gopher-lua"
 )
 
 const (
@@ -114,6 +116,17 @@ func (eh *EventHandler) Execute(t *TextEvent) {
 		eh.RedoStack = new(Stack)
 	}
 	eh.UndoStack.Push(t)
+
+	for _, pl := range loadedPlugins {
+		ret, err := Call(pl+".onBeforeTextEvent", t)
+		if err != nil && !strings.HasPrefix(err.Error(), "function does not exist") {
+			TermMessage(err)
+		}
+		if val, ok := ret.(lua.LBool); ok && val == lua.LFalse {
+			return
+		}
+	}
+
 	ExecuteTextEvent(t, eh.buf)
 }
 

cmd/micro/micro.go

@@ -5,6 +5,7 @@ import (
 	"fmt"
 	"io/ioutil"
 	"os"
+	"path/filepath"
 	"runtime"
 	"strings"
 
@@ -310,6 +311,14 @@ func main() {
 	L.SetGlobal("GetLeadingWhitespace", luar.New(L, GetLeadingWhitespace))
 	L.SetGlobal("MakeCompletion", luar.New(L, MakeCompletion))
 	L.SetGlobal("NewBuffer", luar.New(L, NewBuffer))
+	L.SetGlobal("RuneStr", luar.New(L, func(r rune) string {
+		return string(r)
+	}))
+	L.SetGlobal("Loc", luar.New(L, func(x, y int) Loc {
+		return Loc{x, y}
+	}))
+	L.SetGlobal("JoinPaths", luar.New(L, filepath.Join))
+	L.SetGlobal("configDir", luar.New(L, configDir))
 
 	// Used for asynchronous jobs
 	L.SetGlobal("JobStart", luar.New(L, JobStart))

cmd/micro/rtfiles.go

@@ -145,11 +145,11 @@ func PluginListRuntimeFiles(fileType string) []string {
 
 // PluginAddRuntimeFile adds a file to the runtime files for a plugin
 func PluginAddRuntimeFile(plugin, filetype, path string) {
-	fullpath := configDir + "/plugins/" + plugin + "/" + path
+	fullpath := filepath.Join(configDir, "plugins", plugin, path)
 	if _, err := os.Stat(fullpath); err == nil {
 		AddRuntimeFile(filetype, realFile(fullpath))
 	} else {
-		fullpath = "runtime/plugins/" + plugin + "/" + path
+		fullpath = path.Join("runtime", "plugins", plugin, path)
 		AddRuntimeFile(filetype, assetFile(fullpath))
 	}
 }

runtime/help/plugins.md

@@ -43,12 +43,20 @@ for functions are given using Go's type system):
 * `OS`: variable which gives the OS micro is currently running on (this is the same
 as Go's GOOS variable, so `darwin`, `windows`, `linux`, `freebsd`...)
 
+* `configDir`: contains the path to the micro configuration files
+
 * `tabs`: a list of all the tabs currently in use
 
 * `curTab`: the index of the current tabs in the tabs list
 
 * `messenger`: lets you send messages to the user or create prompts
 
+* `RuneStr(r rune) string`: returns a string containing the given rune
+
+* `Loc(x, y int) Loc`: returns a new `Loc` struct
+
+* `JoinPaths(dir... string) string` combines multiple directories to a full path
+
 * `GetOption(name string)`: returns the value of the requested option
 
 * `AddOption(name string, value interface{})`: sets the given option with the given