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What is catamorphism? Why is this SRFI stalled? Amirouche (02 Dec 2021 11:19 UTC)
Re: What is catamorphism? Why is this SRFI stalled? Marc Nieper-Wißkirchen (02 Dec 2021 11:33 UTC)
Re: What is catamorphism? Why is this SRFI stalled? Panicz Maciej Godek (02 Dec 2021 13:08 UTC)

What is catamorphism? Why is this SRFI stalled? Amirouche 02 Dec 2021 11:19 UTC

A) What is a catamorphism?

B) What is required to move this SRFI forward?

I like the specification. Tho, there is something unclear. The specified (recommended?)
pattern matching language is the one found inside the section:

  Quasi-quotation is the preferred way of expressing patterns

Where the following grammar appears:

  pat ::= identifier                      anything, and binds identifier
        | _                               anything
        | ()                              the empty list
        | #t                              #t
        | #f                              #f
        | string                          a string
        | number                          a number
        | character                       a character
        | 'sexp                           an s-expression
        | 'symbol                         a symbol (special case of s-expr)
        | `qp                             a quasi-pattern

  quasi-patterns:                 matches:

  qp  ::= ()                              the empty list
        | #t                              #t
        | #f                              #f
        | string                          a string
        | number                          a number
        | character                       a character
        | identifier                      a symbol
        | (qp_1 ... qp_n)                 list of n elements
        | (qp_1 ... qp_n . qp_{n+1})      list of n or more
                                          of remainder must match qp_n+1
        | ,pat                            a pattern

I think there is mistake with the pat production rule
for the empty list. An empty list is '(). Do I miss something?