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|
(.module:
lux
(lux (control [monad #+ do]
["ex" exception #+ exception:])
(data [ident]
[number]
[product]
[maybe]
(coll [list "list/" Functor<List>]
[dict #+ Dict])
text/format)
[macro]
(macro [code])
(lang [type]
(type ["tc" check])))
(luxc ["&" lang]
(lang ["&." scope]
["&." module]
["la" analysis]
(analysis ["&." common]
["&." inference]))))
(exception: #export Invalid-Variant-Type)
(exception: #export Invalid-Tuple-Type)
(exception: #export Not-Quantified-Type)
(exception: #export Cannot-Analyse-Variant)
(exception: #export Cannot-Analyse-Tuple)
(exception: #export Cannot-Infer-Numeric-Tag)
(exception: #export Record-Keys-Must-Be-Tags)
(exception: #export Cannot-Repeat-Tag)
(exception: #export Tag-Does-Not-Belong-To-Record)
(exception: #export Record-Size-Mismatch)
(def: #export (analyse-sum analyse tag valueC)
(-> &.Analyser Nat Code (Meta la.Analysis))
(do macro.Monad<Meta>
[expectedT macro.expected-type]
(&.with-stacked-errors
(function [_] (Cannot-Analyse-Variant (format " Type: " (%type expectedT) "\n"
" Tag: " (%n tag) "\n"
"Expression: " (%code valueC))))
(case expectedT
(#.Sum _)
(let [flat (type.flatten-variant expectedT)
type-size (list.size flat)]
(case (list.nth tag flat)
(#.Some variant-type)
(do @
[valueA (&.with-type variant-type
(analyse valueC))
temp &scope.next-local]
(wrap (la.sum tag type-size temp valueA)))
#.None
(&common.variant-out-of-bounds-error expectedT type-size tag)))
(#.Named name unnamedT)
(&.with-type unnamedT
(analyse-sum analyse tag valueC))
(#.Var id)
(do @
[?expectedT' (&.with-type-env
(tc.read id))]
(case ?expectedT'
(#.Some expectedT')
(&.with-type expectedT'
(analyse-sum analyse tag valueC))
_
## Cannot do inference when the tag is numeric.
## This is because there is no way of knowing how many
## cases the inferred sum type would have.
(&.throw Cannot-Infer-Numeric-Tag (format " Type: " (%type expectedT) "\n"
" Tag: " (%n tag) "\n"
"Expression: " (%code valueC)))
))
(^template [<tag> <instancer>]
(<tag> _)
(do @
[[instance-id instanceT] (&.with-type-env <instancer>)]
(&.with-type (maybe.assume (type.apply (list instanceT) expectedT))
(analyse-sum analyse tag valueC))))
([#.UnivQ tc.existential]
[#.ExQ tc.var])
(#.Apply inputT funT)
(case funT
(#.Var funT-id)
(do @
[?funT' (&.with-type-env (tc.read funT-id))]
(case ?funT'
(#.Some funT')
(&.with-type (#.Apply inputT funT')
(analyse-sum analyse tag valueC))
_
(&.throw Invalid-Variant-Type (format " Type: " (%type expectedT) "\n"
" Tag: " (%n tag) "\n"
"Expression: " (%code valueC)))))
_
(case (type.apply (list inputT) funT)
#.None
(&.throw Not-Quantified-Type (%type funT))
(#.Some outputT)
(&.with-type outputT
(analyse-sum analyse tag valueC))))
_
(&.throw Invalid-Variant-Type (format " Type: " (%type expectedT) "\n"
" Tag: " (%n tag) "\n"
"Expression: " (%code valueC)))))))
(def: (analyse-typed-product analyse membersC+)
(-> &.Analyser (List Code) (Meta la.Analysis))
(do macro.Monad<Meta>
[expectedT macro.expected-type]
(loop [expectedT expectedT
membersC+ membersC+]
(case [expectedT membersC+]
## If the tuple runs out, whatever expression is the last gets
## matched to the remaining type.
[tailT (#.Cons tailC #.Nil)]
(&.with-type tailT
(analyse tailC))
## If the type and the code are still ongoing, match each
## sub-expression to its corresponding type.
[(#.Product leftT rightT) (#.Cons leftC rightC)]
(do @
[leftA (&.with-type leftT
(analyse leftC))
rightA (recur rightT rightC)]
(wrap (` [(~ leftA) (~ rightA)])))
## If, however, the type runs out but there is still enough
## tail, the remaining elements get packaged into another
## tuple, and analysed through the intermediation of a
## temporary local variable.
## The reason for this is that it is assumed that the type of
## the tuple represents the expectations of the user.
## If the type is for a 3-tuple, but a 5-tuple is provided, it
## is assumed that the user intended the following layout:
## [0, 1, [2, 3, 4]]
## but that, for whatever reason, it was written in a flat
## way.
## The reason why an intermediate variable is used is that if
## the code was just re-written with just tuple nesting, the
## resulting analysis would have undone the explicity nesting,
## since Product nodes rely on nesting inherently, thereby
## blurring the line between what was wanted (the separation)
## and what was analysed.
[tailT tailC]
(macro.with-gensyms [g!tail]
(&.with-type tailT
(analyse (` ("lux case" [(~+ tailC)]
(~ g!tail)
(~ g!tail))))))
))))
(def: #export (analyse-product analyse membersC)
(-> &.Analyser (List Code) (Meta la.Analysis))
(do macro.Monad<Meta>
[expectedT macro.expected-type]
(&.with-stacked-errors
(function [_] (Cannot-Analyse-Tuple (format " Type: " (%type expectedT) "\n"
"Expression: " (%code (` [(~+ membersC)])))))
(case expectedT
(#.Product _)
(analyse-typed-product analyse membersC)
(#.Named name unnamedT)
(&.with-type unnamedT
(analyse-product analyse membersC))
(#.Var id)
(do @
[?expectedT' (&.with-type-env
(tc.read id))]
(case ?expectedT'
(#.Some expectedT')
(&.with-type expectedT'
(analyse-product analyse membersC))
_
## Must do inference...
(do @
[membersTA (monad.map @ (|>> analyse &common.with-unknown-type)
membersC)
_ (&.with-type-env
(tc.check expectedT
(type.tuple (list/map product.left membersTA))))]
(wrap (la.product (list/map product.right membersTA))))))
(^template [<tag> <instancer>]
(<tag> _)
(do @
[[instance-id instanceT] (&.with-type-env <instancer>)]
(&.with-type (maybe.assume (type.apply (list instanceT) expectedT))
(analyse-product analyse membersC))))
([#.UnivQ tc.existential]
[#.ExQ tc.var])
(#.Apply inputT funT)
(case funT
(#.Var funT-id)
(do @
[?funT' (&.with-type-env (tc.read funT-id))]
(case ?funT'
(#.Some funT')
(&.with-type (#.Apply inputT funT')
(analyse-product analyse membersC))
_
(&.throw Invalid-Tuple-Type (format " Type: " (%type expectedT) "\n"
"Expression: " (%code (` [(~+ membersC)]))))))
_
(case (type.apply (list inputT) funT)
#.None
(&.throw Not-Quantified-Type (%type funT))
(#.Some outputT)
(&.with-type outputT
(analyse-product analyse membersC))))
_
(&.throw Invalid-Tuple-Type (format " Type: " (%type expectedT) "\n"
"Expression: " (%code (` [(~+ membersC)]))))
))))
(def: #export (analyse-tagged-sum analyse tag valueC)
(-> &.Analyser Ident Code (Meta la.Analysis))
(do macro.Monad<Meta>
[tag (macro.normalize tag)
[idx group variantT] (macro.resolve-tag tag)
expectedT macro.expected-type]
(case expectedT
(#.Var _)
(do @
[#let [case-size (list.size group)]
inferenceT (&inference.variant idx case-size variantT)
[inferredT valueA+] (&inference.general analyse inferenceT (list valueC))
temp &scope.next-local]
(wrap (la.sum idx case-size temp (|> valueA+ list.head maybe.assume))))
_
(analyse-sum analyse idx valueC))))
## There cannot be any ambiguity or improper syntax when analysing
## records, so they must be normalized for further analysis.
## Normalization just means that all the tags get resolved to their
## canonical form (with their corresponding module identified).
(def: #export (normalize record)
(-> (List [Code Code]) (Meta (List [Ident Code])))
(monad.map macro.Monad<Meta>
(function [[key val]]
(case key
[_ (#.Tag key)]
(do macro.Monad<Meta>
[key (macro.normalize key)]
(wrap [key val]))
_
(&.throw Record-Keys-Must-Be-Tags (format " Key: " (%code key) "\n"
"Record: " (%code (code.record record))))))
record))
## Lux already possesses the means to analyse tuples, so
## re-implementing the same functionality for records makes no sense.
## Records, thus, get transformed into tuples by ordering the elements.
(def: #export (order record)
(-> (List [Ident Code]) (Meta [(List Code) Type]))
(case record
## empty-record = empty-tuple = unit = []
#.Nil
(:: macro.Monad<Meta> wrap [(list) Unit])
(#.Cons [head-k head-v] _)
(do macro.Monad<Meta>
[head-k (macro.normalize head-k)
[_ tag-set recordT] (macro.resolve-tag head-k)
#let [size-record (list.size record)
size-ts (list.size tag-set)]
_ (if (n/= size-ts size-record)
(wrap [])
(&.throw Record-Size-Mismatch
(format " Expected: " (|> size-ts nat-to-int %i) "\n"
" Actual: " (|> size-record nat-to-int %i) "\n"
" Type: " (%type recordT) "\n"
"Expression: " (%code (|> record
(list/map (function [[keyI valueC]]
[(code.tag keyI) valueC]))
code.record)))))
#let [tuple-range (list.n/range +0 (n/dec size-ts))
tag->idx (dict.from-list ident.Hash<Ident> (list.zip2 tag-set tuple-range))]
idx->val (monad.fold @
(function [[key val] idx->val]
(do @
[key (macro.normalize key)]
(case (dict.get key tag->idx)
#.None
(&.throw Tag-Does-Not-Belong-To-Record
(format " Tag: " (%code (code.tag key)) "\n"
"Type: " (%type recordT)))
(#.Some idx)
(if (dict.contains? idx idx->val)
(&.throw Cannot-Repeat-Tag
(format " Tag: " (%code (code.tag key)) "\n"
"Record: " (%code (code.record (list/map (function [[keyI valC]]
[(code.tag keyI) valC])
record)))))
(wrap (dict.put idx val idx->val))))))
(: (Dict Nat Code)
(dict.new number.Hash<Nat>))
record)
#let [ordered-tuple (list/map (function [idx] (maybe.assume (dict.get idx idx->val)))
tuple-range)]]
(wrap [ordered-tuple recordT]))
))
(def: #export (analyse-record analyse members)
(-> &.Analyser (List [Code Code]) (Meta la.Analysis))
(do macro.Monad<Meta>
[members (normalize members)
[membersC recordT] (order members)]
(case membersC
(^ (list singletonC))
(analyse singletonC)
_
(do @
[expectedT macro.expected-type]
(case expectedT
(#.Var _)
(do @
[inferenceT (&inference.record recordT)
[inferredT membersA] (&inference.general analyse inferenceT membersC)]
(wrap (la.product membersA)))
_
(analyse-product analyse membersC))))))
|
