Add syntax highlighting option

src/help.go

@@ -44,6 +44,9 @@ colorscheme: loads the colorscheme stored in ~/.micro/colorschemes/'option'.micr
 
 tabsize: sets the tab size to 'option'
 	default value: '4'
+
+syntax: turns syntax on or off
+	default value: 'on'
 `
 
 // DisplayHelp displays the help txt

src/settings.go

@@ -13,13 +13,14 @@ import (
 var settings Settings
 
 // All the possible settings
-var possibleSettings = []string{"colorscheme", "tabsize", "autoindent"}
+var possibleSettings = []string{"colorscheme", "tabsize", "autoindent", "syntax"}
 
 // The Settings struct contains the settings for micro
 type Settings struct {
 	Colorscheme string `json:"colorscheme"`
 	TabSize     int    `json:"tabsize"`
 	AutoIndent  bool   `json:"autoindent"`
+	Syntax      bool   `json:"syntax"`
 }
 
 // InitSettings initializes the options map and sets all options to their default values
@@ -61,6 +62,7 @@ func DefaultSettings() Settings {
 		Colorscheme: "default",
 		TabSize:     4,
 		AutoIndent:  true,
+		Syntax:      true,
 	}
 }
 
@@ -88,6 +90,17 @@ func SetOption(view *View, args []string) {
 				settings.Colorscheme = value
 				LoadSyntaxFiles()
 				view.buf.UpdateRules()
+			} else if option == "syntax" {
+				if value == "on" {
+					settings.Syntax = true
+				} else if value == "off" {
+					settings.Syntax = false
+				} else {
+					messenger.Error("Invalid value for " + option)
+					return
+				}
+				LoadSyntaxFiles()
+				view.buf.UpdateRules()
 			}
 			err := WriteSettings(filename)
 			if err != nil {

src/view.go

@@ -548,7 +548,9 @@ func (v *View) HandleEvent(event tcell.Event) {
 	if relocate {
 		v.Relocate()
 	}
+	if settings.Syntax {
 		v.matches = Match(v)
+	}
 }
 
 // DisplayView renders the view to the screen
@@ -608,12 +610,19 @@ func (v *View) DisplayView() {
 
 		// Write the line
 		tabchars := 0
-		for colN, ch := range line {
+		runes := []rune(line)
+		for colN := v.leftCol; colN < v.leftCol+v.width; colN++ {
+			if colN >= len(runes) {
+				break
+			}
+			ch := runes[colN]
 			var lineStyle tcell.Style
 			// Does the current character need to be syntax highlighted?
 
 			// if lineN >= v.updateLines[0] && lineN < v.updateLines[1] {
+			if settings.Syntax {
 				highlightStyle = v.matches[lineN][colN]
+			}
 			// } else if lineN < len(v.lastMatches) && colN < len(v.lastMatches[lineN]) {
 			// highlightStyle = v.lastMatches[lineN][colN]
 			// } else {