Use bytes for highlight groups

cmd/micro/highlight/parser.go

@@ -7,6 +7,18 @@ import (
 	"gopkg.in/yaml.v2"
 )
 
+var groups map[string]uint8
+var numGroups uint8
+
+func GetGroup(n uint8) string {
+	for k, v := range groups {
+		if v == n {
+			return k
+		}
+	}
+	return ""
+}
+
 // A Def is a full syntax definition for a language
 // It has a filetype, information about how to detect the filetype based
 // on filename or header (the first line of the file)
@@ -21,7 +33,7 @@ type Def struct {
 // It has a group that the rule belongs to, as well as
 // the regular expression to match the pattern
 type Pattern struct {
-	group string
+	group uint8
 	regex *regexp.Regexp
 }
 
@@ -39,13 +51,17 @@ type Rules struct {
 // region and also rules from the above region do not match inside this region
 // Note that a region may contain more regions
 type Region struct {
-	group  string
+	group  uint8
 	parent *Region
 	start  *regexp.Regexp
 	end    *regexp.Regexp
 	rules  *Rules
 }
 
+func init() {
+	groups = make(map[string]uint8)
+}
+
 // ParseDef parses an input syntax file into a highlight Def
 func ParseDef(input []byte) (s *Def, err error) {
 	// This is just so if we have an error, we can exit cleanly and return the parse error to the user
@@ -155,7 +171,13 @@ func parseRules(input []interface{}, curRegion *Region) (*Rules, error) {
 						return nil, err
 					}
 
-					rules.patterns = append(rules.patterns, &Pattern{group.(string), r})
+					groupStr := group.(string)
+					if _, ok := groups[groupStr]; !ok {
+						numGroups++
+						groups[groupStr] = numGroups
+					}
+					groupNum := groups[groupStr]
+					rules.patterns = append(rules.patterns, &Pattern{groupNum, r})
 				}
 			case map[interface{}]interface{}:
 				// Region
@@ -177,7 +199,12 @@ func parseRegion(group string, regionInfo map[interface{}]interface{}, prevRegio
 	var err error
 
 	region := new(Region)
-	region.group = group
+	if _, ok := groups[group]; !ok {
+		numGroups++
+		groups[group] = numGroups
+	}
+	groupNum := groups[group]
+	region.group = groupNum
 	region.parent = prevRegion
 
 	region.start, err = regexp.Compile(regionInfo["start"].(string))