Sɛnea wobɛpaw Hindley-Milner ne ɔkwan abien a wɔfa so kyerɛw nsɛm

\u003ch2\u003eSɛnea wobɛpaw Hindley-Milner ne akwan abien a wɔfa so kyerɛw\u003c/h2\u003e \u003cp\u003eAsɛm yi de nhumu ne nsɛm a ɛsom bo ma wɔ n'asɛmti ho, na ɛboa ma nimdeɛ kyɛ ne nteaseɛ.\u003c/p\u003e \u003ch3\u003eNneɛma a Wɔde Fa Nneɛma Titiriw\u003c/h3\u003e \u003cp\u003eAkenkanfoɔ bɛtumi ahwɛ kwan sɛ wɔbɛnya mfasoɔ:\u003c/p\u003e \u003cul\u003e na ɛwɔ hɔ \u003cli\u003eNteaseɛ a emu dɔ wɔ asɛmti no ho\u003c/li\u003e \u003cli\u003eNneɛma a wɔde di dwuma a mfaso wɔ so ne wiase ankasa mu mfaso\u003c/li\u003e \u003cli\u003eAnimdefoɔ adwene ne nhwehwɛmu\u003c/li\u003e \u003cli\u003eNsɛm a wɔayɛ no foforo a ɛfa mprempren nkɔso ho\u003c/li\u003e \u003c/ul\u003e na ɛyɛ adwuma \u003ch3\u003eBoɔ a Wɔde Di Dwuma\u003c/h3\u003e \u003cp\u003eNsɛm a ɛyɛ papa te sɛ yei boa ma wɔkyekye nimdeɛ na ɛhyɛ gyinaesie a ɛwɔ nimdeɛ ho nkuran wɔ nnwuma ahodoɔ mu.\u003c/p\u003e

Nsɛmmisa a Wɔtaa Bisa

Nsonsonoe titiriw bɛn na ɛda Hindley-Milner ne bidirectional type inference ntam?

Hindley-Milner infers types globally a enhia nkyerɛkyerɛmu biara, de nkabom di dwuma de deduce type a ɛyɛ general sen biara ma expression biara. Bidirectional typing kyekyɛ adeyɛ no mu abien —hwɛ ne synthesizing —a ɛhwehwɛ sɛ wɔkyerɛkyerɛ mu bi nanso ɛboa type features a ɛyɛ adefo te sɛ higher-rank polymorphism ne dependent types. Paw no gyina sɛ ebia wode nsusuwii a ɛda adi koraa anaasɛ tumi a ɛda adi a nkyerɛkyerɛmu kakraa bi na ɛwɔ mu di kan.

Bere bɛn na ɛsɛ sɛ mede Hindley-Milner type inference di dwuma ma me kasa?

Hindley-Milner yɛ papa bere a wopɛ type inference a edi mũ a ennotations biara nhia, sɛnea wohu wɔ kasa ahorow te sɛ Haskell 98 ne OCaml mu no. Ɛyɛ adwuma yiye ma rank-1 polymorphism ne algebraic data ahorow a ɛyɛ tẽẽ. Sɛ wo kasa nhyehyɛe no de developer osuahu a ɛyɛ tiawa, a nkyerɛkyerɛmu biara nni mu di kan sen type features a ɛkɔ anim a, Hindley-Milner ne paw a emu yɛ den. Mewayz kata akwan abien no nyinaa so wɔ ne module 207 no nyinaa mu gye $19/mo pɛ.

Dɛn ne anohyeto ahorow a ɛwɔ bidirectional type checking mu?

Bidirectional type checking hwehwɛ sɛ programmers de type annotations ma wɔ mmeae bi—mpɛn pii no function parameters ne top-level definitions. Bere a eyi betumi ayɛ te sɛ nea ɛyɛ sintɔ no, saa nkyerɛkyerɛmu ahorow yi yɛ nkrataa na ɛma mfomso nkrasɛm tu mpɔn kɛse. Anohyeto ankasa ne dwumadie a ɛyɛ den a ɛkɔ soro, ɛfiri sɛ ɛsɛ sɛ wokyerɛkyerɛ baabi a nhyehyɛeɛ no dane wɔ nhwehwɛmu ne synthesis modes ntam de kɔ so yɛ soundness.

So metumi de Hindley-Milner ne akwan abien a wɔfa so kyerɛw abom wɔ nhyehyɛe biako mu?

Yiw, nnɛyi compilers pii de hybrid kwan di dwuma. Sɛ nhwɛso no, GHC Haskell de Hindley-Milner di dwuma sɛ fapem nanso ɛdan kɔ akwan abien so hwɛ so ma ɛyɛ ahorow a ɛkorɔn ne ntrɛwmu afoforo. Saa layered strategy yi ma wo implicit inference ma simple code bere a ɛboa advanced features wɔ baabi a wɔde annotations ma. Mewayz adesua module 207, a wobetumi anya $19/mo, nantew fa nhyehyɛe a wɔaka abom a ɛte saa a wɔbɛkyekye mu anammɔn biara.

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