4.3.5 Documenting Signatures
syntax
(defsignature id (super-id ...) pre-flow ...)
Defines a signature id that extends the super-id
signatures. Any elements defined in decoded
pre-flows—
The decoded pre-flows inset under the signature declaration in the typeset output, so no new sections, etc. can be started.
syntax
(defsignature/splice id (super-id ...) pre-flow ...)
Like defsignature, but the decoded pre-flows
are not typeset under the signature declaration, and new sections,
etc. can be started in the pre-flows.
procedure
(signature-desc pre-flow ...) → any/c
pre-flow : pre-flow? 
Produces an opaque value that defsignature recognizes to
outdent in the typeset form. This is useful for text describing the
signature as a whole to appear right after the signature declaration.
syntax
(sigelem sig-id id)
Typesets the identifier id with a hyperlink to its definition
as a member of the signature named by sig-id.