Eli does not separate the specification of tokens from the specification of the language structure, so there is no specification here of Input or InputElements. The definition of InputElement given here simply collects all of the regular expressions defining those elements:
White space is defined in the next section.
Separators and operators do not have individual lexical descriptions in an Eli specification. They appear as literal terminals in the grammar, and their lexical descriptions are extracted from the grammar by Eli.