src/Store.bend source

src/Store.bend on the hub · documented module

import Baseimport mylsm-lsm-store@0.3.1.0/mylsm.bend as MyLsmStoreimport mylsm-lsm-store@0.3.1.0/src/Db.bend as DbTypes# Session effects for ber-core. Op is a newtype over MyLSM Sess and Handle# over MyLSM Db: ber-core names THESE types, and this module is the ONLY one# naming MyLSM. do-blocks desugar through Op.bind/Op.pure exactly like Sess.# Bend has no value projection: inner sessions unwrap via Op.inner (match on# the parameter), never `op.run`; computed pairs thread through helpers.# One session step chain; the answer type rides along.type Op<a, -A: Kind(a)> is Kind(a <&> &1):  Op{run: MyLsmStore.Sess<a, A>}# An opened store handle; affine, threaded through run_op.type Handle is Type:  Handle{db: DbTypes.Db}# Unwraps the inner session for translators like bind and run_op.def Op.inner(b, -B: Kind(b), op: Op<b, B>) -> MyLsmStore.Sess<b, B>:  match op:    case Op{inner_sess}:      inner_sess# Lifts a pure value; what `return` desugars to inside do-blocks.def Op.pure(a, -A: Kind(a), val: A) -> Op<a, A>:  Op{MyLsmStore.Sess.pure(a, A, val)}# Sequences two ops; what `<-` desugars to inside do-blocks.def Op.bind(a, -A: Kind(a), -B: Kind(a), op: Op<a, A>, fun: A -> Op<a, B>) -> Op<a, B>:  Op{MyLsmStore.Sess.bind(a, A, B, Op.inner(a, A, op), x => Op.inner(a, B, fun(x)))}# Writes one key.def oput(+key: String, +val: String) -> Op<&2, Unit>:  Op{MyLsmStore.sput(key, val)}# Reads one key; missing reads as None.def oget(+key: String) -> Op<&2, Maybe<&2, String>>:  Op{MyLsmStore.sget(key)}# Deletes one key.def odel(+key: String) -> Op<&2, Unit>:  Op{MyLsmStore.sdel(key)}# Opens a store handle over a directory label.def open_store(+dir: String) -> Handle:  Handle{MyLsmStore.open(dir)}# Rewraps a computed runner pair into Handle form.def rewrap_pair(a, -A: Kind(a), computed_pair: DbTypes.Db & A) -> Handle & A:  match computed_pair:    case (db_next, answer):      (Handle{db_next}, answer)# Executes a whole op chain against a handle.def run_op(a, -A: Kind(a), store: Handle, op: Op<a, A>) -> Handle & A:  match store:    case Handle{db}:      rewrap_pair(a, A, MyLsmStore.run_sess(a, A, db, Op.inner(a, A, op)))