basic: rename and document queue related methods

Signed-off-by: Alejandro Mery <amery@jpi.io>

basic/token.go

@@ -32,21 +32,21 @@ func (dec *decoder) executeFinal() {
 func (dec *decoder) execute(typ parser.TokenType) {
 	switch typ {
 	case parser.TokenSectionEnd:
-		name1, ok1 := dec.getValue(1, parser.TokenSectionName)
+		name1, ok1 := dec.queueValue(1, parser.TokenSectionName)
 
 		if ok1 {
-			name2, ok2 := dec.getValue(2, parser.TokenSectionSubname)
+			name2, ok2 := dec.queueValue(2, parser.TokenSectionSubname)
 
 			dec.addSection(name1, name2, ok2)
 		}
 
-		dec.reset()
+		dec.queueReset()
 	case parser.TokenFieldValue:
-		key, _ := dec.getValue(0, parser.TokenFieldKey)
-		value, _ := dec.getValue(1, parser.TokenFieldValue)
+		key, _ := dec.queueValue(0, parser.TokenFieldKey)
+		value, _ := dec.queueValue(1, parser.TokenFieldValue)
 
 		dec.addField(key, value)
-		dec.reset()
+		dec.queueReset()
 	}
 }
 
@@ -82,7 +82,8 @@ func (dec *decoder) addField(key, value string) {
 	}
 }
 
-func (dec *decoder) getValue(idx int, typ parser.TokenType) (string, bool) {
+// queueValue extracts the value of element on the queue if the type matches.
+func (dec *decoder) queueValue(idx int, typ parser.TokenType) (string, bool) {
 	switch {
 	case idx < 0 || idx >= len(dec.queue):
 		// out of range
@@ -95,40 +96,48 @@ func (dec *decoder) getValue(idx int, typ parser.TokenType) (string, bool) {
 	}
 }
 
-func (dec *decoder) reset() {
+// queueReset removes all tokens from the queue
+func (dec *decoder) queueReset() {
 	dec.queue = dec.queue[:0]
 }
 
-func (dec *decoder) depth(depth int) bool {
+// queueDepth confirms the current depth of the queue
+func (dec *decoder) queueDepth(depth int) bool {
 	return len(dec.queue) == depth
 }
 
-func (dec *decoder) depthAfter(depth int, typ parser.TokenType) bool {
-	_, ok := dec.getValue(depth-1, typ)
-	if ok {
-		return len(dec.queue) == depth
+// queueDepthType confirms the current depth of the queue and the type of the last
+// element.
+func (dec *decoder) queueDepthType(depth int, typ parser.TokenType) bool {
+	if dec.queueDepth(depth) {
+		return dec.queueType(depth-1, typ)
 	}
 	return false
 }
 
+// queueType tells if the specified element on the queue is of the required type.
+func (dec *decoder) queueType(idx int, typ parser.TokenType) bool {
+	_, ok := dec.queueValue(idx, typ)
+	return ok
+}
+
 func (dec *decoder) typeOK(typ parser.TokenType) bool {
 	switch typ {
 	case parser.TokenSectionStart, parser.TokenFieldKey:
 		// first token only
-		return dec.depth(0)
+		return dec.queueDepth(0)
 	case parser.TokenSectionName:
 		// right after TokenSectionStart
-		return dec.depthAfter(1, parser.TokenSectionStart)
+		return dec.queueDepthType(1, parser.TokenSectionStart)
 	case parser.TokenSectionSubname:
 		// right after TokenSectionName
-		return dec.depthAfter(2, parser.TokenSectionName)
+		return dec.queueDepthType(2, parser.TokenSectionName)
 	case parser.TokenSectionEnd:
 		// only on a section with name
-		_, ok := dec.getValue(1, parser.TokenSectionName)
-		return ok
+		return dec.queueType(1, parser.TokenSectionName)
 	case parser.TokenFieldValue:
 		// right after a TokenFieldKey
-		return dec.depthAfter(1, parser.TokenFieldKey)
+		return dec.queueDepthType(1, parser.TokenFieldKey)
 	default:
 		// never
 		return false
@@ -149,6 +158,8 @@ func (dec *decoder) OnToken(pos lexer.Position, typ parser.TokenType, value stri
 		return nil
 	default:
 		// unacceptable
-		return newErrInvalidToken(t)
+		err := newErrInvalidToken(t)
+		dec.executeFinal()
+		return err
 	}
 }