Fixes issue #7.

Removed the neccessary to have blocks in the root level. It is still disallowed to have two or more blocks with the same name. Added tests for inheritance (extends/block-tags).

tags_block.go

@@ -44,10 +44,7 @@ func (node *tagBlockNode) Execute(ctx *ExecutionContext) (string, error) {
 }
 
 func tagBlockParser(doc *Parser, start *Token, arguments *Parser) (INodeTag, error) {
-	if doc.template.level > 1 {
-		return nil, arguments.Error("The 'block' tag can only defined on root level (especially no nesting).", start)
-	}
-
+	// TODO: Add {% endblock <blockname> %}-support since Django supports this for better readability
 	wrapper, err := doc.WrapUntilTag("endblock")
 	if err != nil {
 		return nil, err
@@ -74,7 +71,7 @@ func tagBlockParser(doc *Parser, start *Token, arguments *Parser) (INodeTag, err
 	if !has_block {
 		tpl.blocks[name_token.Val] = wrapper
 	} else {
-		return nil, arguments.Error("Block already defined", nil)
+		return nil, arguments.Error(fmt.Sprintf("Block named '%s' already defined", name_token.Val), nil)
 	}
 
 	return &tagBlockNode{name: name_token.Val}, nil

template_tests/extends.tpl

@@ -0,0 +1,3 @@
+{% extends "inheritance/base.tpl" %}
+
+{% block content %}Extends' content{% endblock %}

template_tests/extends.tpl.out

@@ -0,0 +1 @@
+Start#This is base's bodyExtends' content#End

template_tests/inheritance/base.tpl

@@ -0,0 +1,3 @@
+{% extends "inheritance2/skeleton.tpl" %}
+
+{% block body %}This is base's body{% block content %}Default content{% endblock %}{% endblock %}

template_tests/inheritance/inheritance2/skeleton.tpl

@@ -0,0 +1 @@
+Start#{% block body %}Default body{% endblock %}#End