Improve api

README.md

@@ -124,7 +124,7 @@ var defs []*highlight.Def
 ...
 
 def := highlight.DetectFiletype(defs, filename, firstLine)
-fmt.Println("Filetype is", def.ft)
+fmt.Println("Filetype is", def.FileType)
 ```
 
 For a full example, see the [`syncat`](./examples) example which acts like cat but will syntax highlight the output (if highlight recognizes the filetype).

examples/syncat.go

@@ -39,7 +39,7 @@ func main() {
 
 	h := highlight.NewHighlighter(def)
 
-	matches := h.Highlight(string(fileSrc))
+	matches := h.HighlightString(string(fileSrc))
 
 	lines := strings.Split(string(fileSrc), "\n")
 	for lineN, l := range lines {

ftdetect.go

@@ -12,5 +12,8 @@ func DetectFiletype(defs []*Def, filename string, firstLine []byte) *Def {
 		}
 	}
 
-	return nil
+	emptyDef := new(Def)
+	emptyDef.FileType = "Unknown"
+	emptyDef.rules = new(Rules)
+	return emptyDef
 }

highlighter.go

@@ -21,7 +21,7 @@ func combineLineMatch(src, dst LineMatch) LineMatch {
 type State *Region
 
 type LineStates interface {
-	Lines() [][]byte
+	LineData() [][]byte
 	State(lineN int) State
 	SetState(lineN int, s State)
 }
@@ -173,7 +173,7 @@ func (h *Highlighter) highlightEmptyRegion(start int, canMatchEnd bool, lineNum
 	return highlights
 }
 
-func (h *Highlighter) Highlight(input string) []LineMatch {
+func (h *Highlighter) HighlightString(input string) []LineMatch {
 	lines := strings.Split(input, "\n")
 	var lineMatches []LineMatch
 
@@ -190,10 +190,35 @@ func (h *Highlighter) Highlight(input string) []LineMatch {
 	return lineMatches
 }
 
-func (h *Highlighter) ReHighlight(input LineStates, startline int) []LineMatch {
-	lines := input.Lines()
+func (h *Highlighter) Highlight(input LineStates, startline int) []LineMatch {
+	lines := input.LineData()
 	var lineMatches []LineMatch
 
+	for i := startline; i < len(lines); i++ {
+		line := []byte(lines[i])
+
+		if i == 0 || h.lastRegion == nil {
+			lineMatches = append(lineMatches, h.highlightEmptyRegion(0, true, i, line))
+		} else {
+			lineMatches = append(lineMatches, h.highlightRegion(0, true, i, line, h.lastRegion))
+		}
+
+		curState := h.lastRegion
+
+		input.SetState(i, curState)
+	}
+
+	return lineMatches
+}
+
+func (h *Highlighter) ReHighlight(input LineStates, startline int) []LineMatch {
+	lines := input.LineData()
+	var lineMatches []LineMatch
+
+	h.lastRegion = nil
+	if startline > 0 {
+		h.lastRegion = input.State(startline - 1)
+	}
 	for i := startline; i < len(lines); i++ {
 		line := []byte(lines[i])
 

parser.go

@@ -12,7 +12,7 @@ import (
 // on filename or header (the first line of the file)
 // Then it has the rules which define how to highlight the file
 type Def struct {
-	ft       string
+	FileType string
 	ftdetect []*regexp.Regexp
 	rules    *Rules
 }
@@ -68,7 +68,7 @@ func ParseDef(input []byte) (s *Def, err error) {
 		if k == "filetype" {
 			filetype := v.(string)
 
-			s.ft = filetype
+			s.FileType = filetype
 		} else if k == "detect" {
 			ftdetect := v.(map[interface{}]interface{})
 			if len(ftdetect) >= 1 {