The draft 034 grammar productions do not allow for a separate prefix/suffix for a simple type as distinguished from the element having that type. Draft 034 does allow for an element of complex type to have a separate prefix and suffix for the element itself and another one for the sequence or choice inside it. I've come to believe this is a mistake and I suggest a fix below. Right now the grammar is: Element = SimpleElement | ComplexElement SimpleElement = Prefix SimpleContent Suffix SimpleContent = StringText // terminal. No more prefixes/suffixes ComplexElement = Prefix ComplexContent Suffix ComplexContent = Sequence | Choice Sequence = Prefix SequenceContent Suffix Choice = Prefix ChoiceContent Suffix So, if I do: <complexType dfdl:initiator="[" dfdl:terminator="]"> ... <element name="y"> <complexType> <sequence dfdl:separator="," > <element name="x" type="int"/> <element name="z" type="int"/> </sequence> </complexType> </element> ... </complexType> I have two prefix opportunities. I can flatten the productions above to: ComplexElement = Prefix Prefix SequenceContent Suffix Suffix An instance of this type would look like [[[5],[6]]]. That is, for complex types, there are separate prefix and suffix regions for the element, and for the model-group which makes up its content. The first [ initiates element y. The second [ initiates the sequence The third [ initiates element x. This same behavior is not true for simple types: <complexType dfdl:initiator="[" dfdl:terminator="]"> ... <element name="y" > <simpleType> <restriction base="int"/> </simpleType> </element> ... </complexType> This can only mean [5]. The grammar, as formulated in draft 034, does not allow for more than one prefix or suffix. The [ is the initiator of element y. I believe we should fix this as follows. New grammar: Element = SimpleElement | ComplexElement SimpleElement = Prefix SimpleContent Suffix SimpleContent = StringText ComplexElement = ComplexContent // Note: no more surrounding prefix suffix. ComplexContent = Sequence | Choice Sequence = Prefix SequenceContent Suffix Choice = Prefix ChoiceContent Suffix The above grammar arranges for an element of complex type and its model group to both taken together specify a single prefix and suffix. Revisiting our example (just repeating it here): <complexType dfdl:initiator="[" dfdl:terminator="]"> ... <element name="y"> <complexType> <sequence dfdl:separator="," > <element name="x" type="int"/> <element name="z" type="int"/> </sequence> </complexType> </element> ... </complexType> An instance now would look like [[5],[6]] The first [ is the initiator of element y, which is the same as the initiator of the sequence that is its type. The second [ is the initiator of element x. (which is the same as the initiator of the int that is its type) I believe this is more sensible, as it makes the behavior of simple and complex types more similar. It begs the question of how one combines conflicting properties on an element with the properties on the type, and even the model group inside the type in the complex case. Because all these properties are describing the same syntax fields in the grammar. That's a separate topic in a subsequent email.