Carp/core/Tuples.carp

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(defmodule Dynamic
(private deftuple-type-)
(hidden deftuple-type-)
(defndynamic deftuple-type- [name props]
(list 'deftype (cons name props)
(collect-into (flatten (map (fn [x] (list x x)) props)) array)))
(private deftuple-lt-)
(hidden deftuple-lt-)
(defndynamic deftuple-lt- [name props]
(if (empty? props)
'false
(let [fst (Symbol.prefix name (car props))]
(if (= (length props) 1)
(list '< (list fst 't1) (list fst 't2))
(list 'if (list '= (list fst 't1) (list fst 't2))
(deftuple-lt- name (cdr props))
(list '< (list fst 't1) (list fst 't2)))))))
; this is basically just a giant template
(private deftuple-module-)
(hidden deftuple-module-)
(defndynamic deftuple-module- [name props]
(let [sname (Symbol.str name)
module-name (Symbol.concat [name 'Ref])]
(list 'do
(list 'defmodule module-name
(list 'defn '= ['t1 't2]
(cons 'and*
(map (fn [p]
(list '=
(list (Symbol.prefix name p) 't1)
(list (Symbol.prefix name p) 't2)))
props)))
(list 'implements '= (Symbol.prefix module-name '=))
(list 'defn '< ['t1 't2] (deftuple-lt- name props))
(list 'implements '< (Symbol.prefix module-name '<))
(list 'defn '> ['t1 't2] (list (Symbol.prefix module-name '<) 't2 't1))
(list 'implements '> (Symbol.prefix module-name '>)))
(list 'defmodule name
(list 'doc 'init-from-refs
(String.concat ["initializes a `" sname "` from member references."]))
(let [prop-vars (map (fn [x] (Symbol.concat [x '-val])) props)]
(list 'defn 'init-from-refs (collect-into prop-vars array)
(cons 'init (map (fn [x] (list 'copy x)) prop-vars))))
(list 'defn '= ['t1 't2]
(cons 'and*
(map (fn [p] (list '= (list p '(ref t1)) (list p '(ref t2)))) props)))
(list 'implements '= (Symbol.prefix name '=))
(list 'defn '< ['t1 't2]
(list (Symbol.prefix module-name '<) '(ref t1) '(ref t2)))
(list 'implements '< (Symbol.prefix name '<))
(list 'defn '> ['t1 't2]
(list (Symbol.prefix module-name '>) '(ref t1) '(ref t2)))
(list 'implements '> (Symbol.prefix name '>))
(list 'doc 'reverse
(String.concat ["reverses a `" sname "` by reversing its member positions."]))
(list 'defn 'reverse ['t]
(cons 'init (map (fn [x] (list 'copy (list x 't))) (reverse props))))
(list 'defn 'zero [] (cons 'init (map (fn [_] '(zero)) props))))
(list 'implements 'zero (Symbol.prefix name 'zero))
;(list 'doc 'zero
; (String.concat [
; "initializes a `" sname
; "` by calling `zero` for all its members. `zero` must be defined for all member types."]))
)))
(doc deftuple "defines a tuple type.
For example:
```
; is the definition of Pair in the stdlib
(deftuple Pair a b)
```")
(defmacro deftuple [name :rest props]
(do
(eval (deftuple-type- name props))
(eval (deftuple-module- name props))
))
)
(doc Pair "is a 2-tuple, i.e. a datatype with two members.")
(deftuple Pair a b)
(doc Triple "is a 3-tuple, i.e. a datatype with three members.")
(deftuple Triple a b c)
(doc Quadruple "is a 4-tuple, i.e. a datatype with three members.")
(deftuple Quadruple a b c d)