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|
(.module: {#.doc "Codecs for values in the JSON format."}
[lux #*
[control
[monad (#+ do Monad)]
[equivalence (#+ Equivalence)]
codec
["p" parser]]
[data
["." bit]
maybe
["e" error]
["." sum]
["." product]
[number ("frac/." Codec<Text,Frac>) ("nat/." Codec<Text,Nat>)
["." i64]]
["." text ("text/." Equivalence<Text>)
["l" lexer]
format]
[format
["//" json (#+ JSON)]]
[collection
["." list ("list/." Fold<List> Monad<List>)]
["." row (#+ Row row) ("row/." Monad<Row>)]
["d" dictionary]]]
[time
## ["i" instant]
## ["du" duration]
["da" date]]
[macro (#+ with-gensyms)
["s" syntax (#+ syntax:)]
["." code]
["." poly (#+ poly:)]]
["." type
["." unit]]])
(def: tag
(-> Nat Frac)
(|>> .int int-to-frac))
(def: (rec-encode non-rec)
(All [a] (-> (-> (-> a JSON)
(-> a JSON))
(-> a JSON)))
(function (_ input)
(non-rec (rec-encode non-rec) input)))
(def: low-mask Nat (|> 1 (i64.left-shift 32) dec))
(def: high-mask Nat (|> low-mask (i64.left-shift 32)))
(structure: _ (Codec JSON Nat)
(def: (encode input)
(let [high (|> input (i64.and high-mask) (i64.logical-right-shift 32))
low (i64.and low-mask input)]
(#//.Array (row (|> high .int int-to-frac #//.Number)
(|> low .int int-to-frac #//.Number)))))
(def: (decode input)
(<| (//.run input)
//.array
(do p.Monad<Parser>
[high //.number
low //.number])
(wrap (n/+ (|> high frac-to-int .nat (i64.left-shift 32))
(|> low frac-to-int .nat))))))
(structure: _ (Codec JSON Int)
(def: encode (|>> .nat (:: Codec<JSON,Nat> encode)))
(def: decode
(|>> (:: Codec<JSON,Nat> decode) (:: e.Functor<Error> map .int))))
(def: (nullable writer)
{#.doc "Builds a JSON generator for potentially inexistent values."}
(All [a] (-> (-> a JSON) (-> (Maybe a) JSON)))
(function (_ elem)
(case elem
#.None #//.Null
(#.Some value) (writer value))))
(structure: Codec<JSON,Qty>
(All [unit] (Codec JSON (unit.Qty unit)))
(def: encode
(|>> unit.out (:: Codec<JSON,Int> encode)))
(def: decode
(|>> (:: Codec<JSON,Int> decode) (:: e.Functor<Error> map unit.in))))
(poly: Codec<JSON,?>//encode
(with-expansions
[<basic> (do-template [<matcher> <encoder>]
[(do @
[#let [g!_ (code.local-identifier "_______")]
_ <matcher>]
(wrap (` (: (~ (@JSON//encode inputT))
<encoder>))))]
[(poly.exactly Any) (function ((~ g!_) (~ (code.identifier ["" "0"]))) #//.Null)]
[(poly.sub Bit) (|>> #//.Boolean)]
[(poly.sub Nat) (:: (~! ..Codec<JSON,Nat>) (~' encode))]
[(poly.sub Int) (:: (~! ..Codec<JSON,Int>) (~' encode))]
[(poly.sub Frac) (|>> #//.Number)]
[(poly.sub Text) (|>> #//.String)])
<time> (do-template [<type> <codec>]
[(do @
[_ (poly.exactly <type>)]
(wrap (` (: (~ (@JSON//encode inputT))
(|>> (:: <codec> (~' encode)) #//.String)))))]
## [du.Duration du.Codec<Text,Duration>]
## [i.Instant i.Codec<Text,Instant>]
[da.Date da.Codec<Text,Date>]
[da.Day da.Codec<Text,Day>]
[da.Month da.Codec<Text,Month>])]
(do @
[*env* poly.env
#let [@JSON//encode (: (-> Type Code)
(function (_ type)
(` (-> (~ (poly.to-code *env* type)) //.JSON))))]
inputT poly.peek]
($_ p.either
<basic>
<time>
(do @
[unitT (poly.apply (p.after (poly.exactly unit.Qty)
poly.any))]
(wrap (` (: (~ (@JSON//encode inputT))
(:: (~! Codec<JSON,Qty>) (~' encode))))))
(do @
[#let [g!_ (code.local-identifier "_______")
g!key (code.local-identifier "_______key")
g!val (code.local-identifier "_______val")]
[_ _ =val=] (poly.apply ($_ p.and
(poly.exactly d.Dictionary)
(poly.exactly .Text)
Codec<JSON,?>//encode))]
(wrap (` (: (~ (@JSON//encode inputT))
(|>> d.entries
((~! list/map) (function ((~ g!_) [(~ g!key) (~ g!val)])
[(~ g!key) ((~ =val=) (~ g!val))]))
(d.from-list text.Hash<Text>)
#//.Object)))))
(do @
[[_ =sub=] (poly.apply ($_ p.and
(poly.exactly .Maybe)
Codec<JSON,?>//encode))]
(wrap (` (: (~ (@JSON//encode inputT))
((~! ..nullable) (~ =sub=))))))
(do @
[[_ =sub=] (poly.apply ($_ p.and
(poly.exactly .List)
Codec<JSON,?>//encode))]
(wrap (` (: (~ (@JSON//encode inputT))
(|>> ((~! list/map) (~ =sub=)) row.from-list #//.Array)))))
(do @
[#let [g!_ (code.local-identifier "_______")
g!input (code.local-identifier "_______input")]
members (poly.variant (p.many Codec<JSON,?>//encode))]
(wrap (` (: (~ (@JSON//encode inputT))
(function ((~ g!_) (~ g!input))
(case (~ g!input)
(~+ (list/join (list/map (function (_ [tag g!encode])
(list (` ((~ (code.nat tag)) (~ g!input)))
(` (//.json [(~ (code.frac (..tag tag)))
((~ g!encode) (~ g!input))]))))
(list.enumerate members))))))))))
(do @
[g!encoders (poly.tuple (p.many Codec<JSON,?>//encode))
#let [g!_ (code.local-identifier "_______")
g!members (|> (list.size g!encoders)
list.indices
(list/map (|>> nat/encode code.local-identifier)))]]
(wrap (` (: (~ (@JSON//encode inputT))
(function ((~ g!_) [(~+ g!members)])
(//.json [(~+ (list/map (function (_ [g!member g!encode])
(` ((~ g!encode) (~ g!member))))
(list.zip2 g!members g!encoders)))]))))))
## Type recursion
(do @
[[selfC non-recC] (poly.recursive Codec<JSON,?>//encode)
#let [g! (code.local-identifier "____________")]]
(wrap (` (: (~ (@JSON//encode inputT))
((~! ..rec-encode) (.function ((~ g!) (~ selfC))
(~ non-recC)))))))
poly.recursive-self
## Type applications
(do @
[partsC (poly.apply (p.many Codec<JSON,?>//encode))]
(wrap (` ((~+ partsC)))))
## Polymorphism
(do @
[[funcC varsC bodyC] (poly.polymorphic Codec<JSON,?>//encode)]
(wrap (` (: (All [(~+ varsC)]
(-> (~+ (list/map (function (_ varC) (` (-> (~ varC) //.JSON)))
varsC))
(-> ((~ (poly.to-code *env* inputT)) (~+ varsC))
//.JSON)))
(function ((~ funcC) (~+ varsC))
(~ bodyC))))))
poly.parameter
poly.recursive-call
## If all else fails...
(p.fail (format "Cannot create JSON encoder for: " (type.to-text inputT)))
))))
(poly: Codec<JSON,?>//decode
(with-expansions
[<basic> (do-template [<matcher> <decoder>]
[(do @
[_ <matcher>]
(wrap (` (: (~ (@JSON//decode inputT))
<decoder>))))]
[(poly.exactly Any) //.null]
[(poly.sub Bit) //.boolean]
[(poly.sub Nat) (p.codec (~! ..Codec<JSON,Nat>) //.any)]
[(poly.sub Int) (p.codec (~! ..Codec<JSON,Int>) //.any)]
[(poly.sub Frac) //.number]
[(poly.sub Text) //.string])
<time> (do-template [<type> <codec>]
[(do @
[_ (poly.exactly <type>)]
(wrap (` (: (~ (@JSON//decode inputT))
(p.codec <codec> //.string)))))]
## [du.Duration du.Codec<Text,Duration>]
## [i.Instant i.Codec<Text,Instant>]
[da.Date da.Codec<Text,Date>]
[da.Day da.Codec<Text,Day>]
[da.Month da.Codec<Text,Month>])]
(do @
[*env* poly.env
#let [@JSON//decode (: (-> Type Code)
(function (_ type)
(` (//.Reader (~ (poly.to-code *env* type))))))]
inputT poly.peek]
($_ p.either
<basic>
<time>
(do @
[unitT (poly.apply (p.after (poly.exactly unit.Qty)
poly.any))]
(wrap (` (: (~ (@JSON//decode inputT))
(p.codec (~! Codec<JSON,Qty>) //.any)))))
(do @
[[_ _ valC] (poly.apply ($_ p.and
(poly.exactly d.Dictionary)
(poly.exactly .Text)
Codec<JSON,?>//decode))]
(wrap (` (: (~ (@JSON//decode inputT))
(//.object (~ valC))))))
(do @
[[_ subC] (poly.apply (p.and (poly.exactly .Maybe)
Codec<JSON,?>//decode))]
(wrap (` (: (~ (@JSON//decode inputT))
(//.nullable (~ subC))))))
(do @
[[_ subC] (poly.apply (p.and (poly.exactly .List)
Codec<JSON,?>//decode))]
(wrap (` (: (~ (@JSON//decode inputT))
(//.array (p.some (~ subC)))))))
(do @
[members (poly.variant (p.many Codec<JSON,?>//decode))]
(wrap (` (: (~ (@JSON//decode inputT))
($_ p.or
(~+ (list/map (function (_ [tag memberC])
(` (|> (~ memberC)
(p.after (//.number! (~ (code.frac (..tag tag)))))
//.array)))
(list.enumerate members))))))))
(do @
[g!decoders (poly.tuple (p.many Codec<JSON,?>//decode))]
(wrap (` (: (~ (@JSON//decode inputT))
(//.array ($_ p.and (~+ g!decoders)))))))
## Type recursion
(do @
[[selfC bodyC] (poly.recursive Codec<JSON,?>//decode)
#let [g! (code.local-identifier "____________")]]
(wrap (` (: (~ (@JSON//decode inputT))
(p.rec (.function ((~ g!) (~ selfC))
(~ bodyC)))))))
poly.recursive-self
## Type applications
(do @
[[funcC argsC] (poly.apply (p.and Codec<JSON,?>//decode (p.many Codec<JSON,?>//decode)))]
(wrap (` ((~ funcC) (~+ argsC)))))
## Polymorphism
(do @
[[funcC varsC bodyC] (poly.polymorphic Codec<JSON,?>//decode)]
(wrap (` (: (All [(~+ varsC)]
(-> (~+ (list/map (|>> (~) //.Reader (`)) varsC))
(//.Reader ((~ (poly.to-code *env* inputT)) (~+ varsC)))))
(function ((~ funcC) (~+ varsC))
(~ bodyC))))))
poly.parameter
poly.recursive-call
## If all else fails...
(p.fail (format "Cannot create JSON decoder for: " (type.to-text inputT)))
))))
(syntax: #export (Codec<JSON,?> inputT)
{#.doc (doc "A macro for automatically producing JSON codecs."
(type: Variant
(#Case0 Bit)
(#Case1 Text)
(#Case2 Frac))
(type: Record
{#bit Bit
#frac Frac
#text Text
#maybe (Maybe Frac)
#list (List Frac)
#variant Variant
#tuple [Bit Frac Text]
#dict (Dictionary Text Frac)})
(derived: (Codec<JSON,?> Record)))}
(with-gensyms [g!inputs]
(wrap (list (` (: (Codec //.JSON (~ inputT))
(structure (def: (~' encode) ((~! Codec<JSON,?>//encode) (~ inputT)))
(def: ((~' decode) (~ g!inputs)) (//.run (~ g!inputs) ((~! Codec<JSON,?>//decode) (~ inputT))))
)))))))
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