Implement comment tag

README.md

@@ -14,7 +14,7 @@
   - [x] Arrays
   - [ ] Whitespace Control
 - [ ] Tags
-  - [ ] Comment
+  - [x] Comment
   - [ ] Control Flow
     - [x] if/else/elsif
     - [x] unless

chunks/parser.go

@@ -12,21 +12,28 @@ func Parse(chunks []Chunk) (ASTNode, error) {
 		ap *[]ASTNode
 	}
 	var (
-		root  = &ASTSeq{}
-		ap    = &root.Children // pointer to current node accumulation slice
-		ccd   *controlTagDefinition
-		ccn   *ASTControlTag
-		stack []frame // stack of control structures
+		root      = &ASTSeq{}
+		ap        = &root.Children // pointer to current node accumulation slice
+		ccd       *controlTagDefinition
+		ccn       *ASTControlTag
+		stack     []frame // stack of control structures
+		inComment = false
 	)
 	for _, c := range chunks {
-		switch c.Type {
-		case ObjChunkType:
+		switch {
+		case inComment:
+			if c.Type == TagChunkType && c.Tag == "endcomment" {
+				inComment = false
+			}
+		case c.Type == ObjChunkType:
 			*ap = append(*ap, &ASTObject{Chunk: c})
-		case TextChunkType:
+		case c.Type == TextChunkType:
 			*ap = append(*ap, &ASTText{Chunk: c})
-		case TagChunkType:
+		case c.Type == TagChunkType:
 			if cd, ok := findControlTagDefinition(c.Tag); ok {
 				switch {
+				case c.Tag == "comment":
+					inComment = true
 				case cd.requiresParent() && !cd.compatibleParent(ccd):
 					suffix := ""
 					if ccd != nil {

tags/tags_test.go

@@ -16,6 +16,9 @@ var parseErrorTests = []struct{ in, expected string }{
 }
 
 var tagTests = []struct{ in, expected string }{
+	// TODO test whether this requires matching interior tags
+	{"{%comment%}{{a}}{%unknown%}{%endcomment%}", ""},
+
 	{"{%if true%}true{%endif%}", "true"},
 	{"{%if false%}false{%endif%}", ""},
 	{"{%if 0%}true{%endif%}", "true"},