polytropos-beam (empty) → 0.1.0.2
raw patch · 6 files changed
+745/−0 lines, 6 filesdep +basedep +beam-coredep +polytropos-beam
Dependencies added: base, beam-core, polytropos-beam, polytropos-core, polytropos-plugin, tasty, tasty-hunit
Files
- CHANGELOG.md +8/−0
- LICENSE +391/−0
- README.md +42/−0
- polytropos-beam.cabal +57/−0
- src/Polytropos/Beam.hs +153/−0
- test/Main.hs +94/−0
+ CHANGELOG.md view
@@ -0,0 +1,8 @@+# Changelog for polytropos-beam++## 0.1.0.0 — Initial Release++- Beam database entity and table bindings for open rows+- `PolyBeamRow` higher-kinded record schema representation implementing `Beamable`+- Automatic conversion between columnar Beam tables and contiguous `SmallArray` row representations+- Direct projection into database table expressions
+ LICENSE view
@@ -0,0 +1,391 @@+Polytropos Dual Licensing++Copyright (c) 2026, Nadia Yvette Chambers <nadia.yvette.chambers@ik.me>+All rights reserved.++SPDX-License-Identifier: EUPL-1.2 OR Apache-2.0++Polytropos is dual-licensed: you may use, copy, modify, merge, publish,+distribute, sublicense, and/or sell copies of the software under the terms+of EITHER:++1. The European Union Public Licence, version 1.2 (EUPL-1.2), as published by+ the European Commission (available in 23 authentic language versions); OR+2. The Apache License, Version 2.0 (Apache-2.0).++You may choose whichever license best fits your requirements and compliance+environment.++Individual license files are available in the LICENSES/ directory:+- LICENSES/EUPL-1.2.txt+- LICENSES/Apache-2.0.txt++================================================================================+1. 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+ README.md view
@@ -0,0 +1,42 @@+# polytropos-beam++Beam table and database entity bindings for [polytropos](https://github.com/NadiaYvette/polytropos) open rows.++## Overview++`polytropos-beam` bridges open rows with the `beam-core` database library, allowing open records to serve as database table schemas via `PolyBeamRow`.++## Features++- **`PolyBeamRow` Schema**: Higher-kinded table schema implementing `Beamable`.+- **Zero-Copy Column Derivation**: Flattens table columns directly into `SmallArray` row representations.+- **Sub-Row Projection**: Seamlessly slice wide database tables into narrow summary records.++## Quick Example++```haskell+{-# LANGUAGE DataKinds #-}+{-# LANGUAGE OverloadedStrings #-}+{-# OPTIONS_GHC -fplugin=Polytropos.Plugin #-}++import Database.Beam+import Polytropos+import Polytropos.Beam++type UserRow = '[ "id" := Int, "username" := String ]++-- 1. Construct Beam table directly from open record:+userRec :: Record UserRow+userRec = REC { id = 1, username = "Alice" }++userTable :: PolyBeamRow UserRow (TableField UserTable)+userTable = toBeamTable userRec++-- 2. Functional updates with unparenthesized REC_UPD:+updatedUser :: Record UserRow+updatedUser = REC_UPD userRec { username = "Bob" }+```++## License++Dual-licensed under `EUPL-1.2 OR Apache-2.0`.
+ polytropos-beam.cabal view
@@ -0,0 +1,57 @@+cabal-version: 3.0+name: polytropos-beam+version: 0.1.0.2+synopsis: beam database schema integration for polytropos open records+description:+ Integration enabling <https://hackage.haskell.org/package/polytropos polytropos> open records to act as+ <https://hackage.haskell.org/package/beam-core beam-core> database tables and query projections without+ compiler out-of-memory crashes on wide schemas (50+ columns).++ The 'Database.Beam.Schema.Tables.Beamable' instance operates directly over the flat contiguous+ 'Data.Primitive.SmallArray.SmallArray' payload: scaling column count costs exactly one array slot+ rather than exploding generic-representation AST trees during compilation.++ Start at the front door module "Polytropos.Beam" for schema definitions,+ table wrappers, and worked examples.+license: EUPL-1.2 OR Apache-2.0+license-file: LICENSE+author: Nadia Yvette Chambers+maintainer: nadia.yvette.chambers@ik.me+category: Database+homepage: https://github.com/NadiaYvette/polytropos+bug-reports: https://github.com/NadiaYvette/polytropos/issues+extra-doc-files:+ README.md+ , CHANGELOG.md+build-type: Simple++source-repository head+ type: git+ location: https://github.com/NadiaYvette/polytropos+ subdir: packages/polytropos-beam++library+ default-language: GHC2021+ hs-source-dirs: src+ exposed-modules: Polytropos.Beam+ ghc-options: -Wall+ build-depends:+ base >= 4.14 && < 5,+ beam-core >= 0.9 && < 0.12,+ polytropos-core >= 0.1 && < 0.2,+ polytropos-plugin >= 0.1 && < 0.2++test-suite polytropos-beam-test+ type: exitcode-stdio-1.0+ default-language: GHC2021+ hs-source-dirs: test+ main-is: Main.hs+ ghc-options: -Wall -fplugin=Polytropos.Plugin+ build-depends:+ base,+ beam-core,+ polytropos-core,+ polytropos-beam,+ polytropos-plugin,+ tasty,+ tasty-hunit
+ src/Polytropos/Beam.hs view
@@ -0,0 +1,153 @@+{-# LANGUAGE AllowAmbiguousTypes #-}+{-# LANGUAGE DataKinds #-}+{-# LANGUAGE FlexibleContexts #-}+{-# LANGUAGE FlexibleInstances #-}+{-# LANGUAGE MultiParamTypeClasses #-}+{-# LANGUAGE PolyKinds #-}+{-# LANGUAGE RankNTypes #-}+{-# LANGUAGE ScopedTypeVariables #-}++{-# LANGUAGE TypeApplications #-}+{-# LANGUAGE TypeFamilies #-}+{-# LANGUAGE TypeOperators #-}+{-# LANGUAGE UndecidableInstances #-}+{-# OPTIONS_GHC -Wno-orphans #-}++{-|+Module : Polytropos.Beam+Description : beam schema integration for Polytropos open records+Copyright : (c) 2026 The Polytropos Authors+License : EUPL-1.2 OR Apache-2.0+Maintainer : nadia.yvette.chambers@ik.me+Stability : experimental+Portability : non-portable (GHC extensions)++Enables @polytropos@ open records to act as @beam@ database schema tables+without GHC out-of-memory compilation crashes on 50+ columns.++= Architectural Overview & Rationale++== Eliminating Generic Tree Explosion in Beam++A standard beam table is a nominal Haskell record whose 'Beamable' instance is+derived through "GHC.Generics". The resulting binary metadata tree is what causes+quadratic compile times and memory blow-up on tables with 50+ columns.++In @polytropos-beam@, a table is backed by a single flat 'Data.Primitive.SmallArray.SmallArray':+* 'zipBeamFieldsM' executes as a linear lockstep walk over flat array slots.+* 'tblSkeleton' builds the table spine once per row arity.+* @t'BeamTable'@ is a zero-cost newtype wrapper around @RowRep f ProductRowT r ()@.++= When to Use This Module++* When defining large database tables (dozens or hundreds of columns) with the @beam@+ framework while maintaining predictable, instantaneous compilation.++= Worked Example++> {-# LANGUAGE DataKinds #-}+> {-# LANGUAGE OverloadedRecordDot #-}+>+> import Database.Beam+> import Polytropos+> import Polytropos.Beam+>+> type UserRow = '["id" ':= Int, "username" ':= String]+> type UserTable f = BeamTable UserRow f+>+> -- 1. Construct an open record using idiomatic REC syntax:+> userRec :: Record UserRow+> userRec = REC { id = 1, username = "Alice" }+>+> -- 2. Convert to a Beam database table (zero-cost unwrap):+> userTable :: UserTable Identity+> userTable = toBeamTable userRec+>+> -- 3. Functional updates using REC_UPD prior to database serialization:+> updatedUser :: Record UserRow+> updatedUser = REC_UPD userRec { username = "Bob" }+>+> -- 4. Higher-Kinded Data (HKD) partial table with REC_F and REC_UPD_F:+> partialUser :: RecordF Maybe UserRow+> partialUser = REC_F { id = Just 1, username = Nothing }+>+> populatedUser :: RecordF Maybe UserRow+> populatedUser = REC_UPD_F partialUser { username = Just "Bob" }+-}+module Polytropos.Beam+ ( -- * Beam Tables over Polytropos Rows+ BeamTable (..)+ , toBeamTable+ , fromBeamTable+ , beamTableOfSlots++ -- * Row Introspection+ , FieldNames (..)+ ) where++import Data.Functor.Identity (Identity)+import Data.Kind (Type)+import Data.Proxy (Proxy (..))+import GHC.Exts (Any, toList)+import GHC.TypeLits (KnownSymbol, symbolVal)+import Database.Beam.Schema.Tables (Beamable (..), Columnar' (..), Ignored (..))+import Polytropos (Record)+import Polytropos.Core (Pair (..), Rep (..), Row, RowRep (..), RowType (..),+ noInlineUnsafeCo, productRep, repVals)++{-------------------------------------------------------------------------------+ Row introspection+-------------------------------------------------------------------------------}++-- | The field names of a row, in row order, reified from the type level.+-- These are the default column names beam derives from the row symbols.+class FieldNames (r :: Row) where+ fieldNames :: Proxy r -> [String]++instance FieldNames '[] where+ fieldNames _ = []++instance (KnownSymbol n, FieldNames r) => FieldNames ((n ':= a) ': r) where+ fieldNames _ = symbolVal (Proxy @n) : fieldNames (Proxy @r)++{-------------------------------------------------------------------------------+ Beam tables+-------------------------------------------------------------------------------}++-- | A @polytropos@ row presented as a beam table with column functor @f@.+--+-- Zero cost: unwraps to exactly the same t'Polytropos.Core.Rep' spine as the+-- corresponding 'Record' (for @f ~ Identity@).+newtype BeamTable (r :: Row) (f :: Type -> Type)+ = BeamTable (RowRep f ProductRowT r ())++-- | View a record as a beam table (zero-cost newtype wrap).+toBeamTable :: Record r -> BeamTable r Identity+toBeamTable (RowRep rep) = BeamTable (RowRep rep)++-- | View a beam table as a record (zero-cost newtype unwrap).+fromBeamTable :: BeamTable r Identity -> Record r+fromBeamTable (BeamTable (RowRep rep)) = RowRep rep++-- | Build a table from payload slots, in row order. The slot list must have+-- exactly the row's arity; a shorter list yields a partially filled table+-- that will misbehave if traversed, so prefer 'toBeamTable'.+beamTableOfSlots :: [f Any] -> BeamTable r f+beamTableOfSlots slots = BeamTable (RowRep (productRep slots))++instance FieldNames r => Beamable (BeamTable r) where+ zipBeamFieldsM combine (BeamTable (RowRep (Rep t fv))) (BeamTable (RowRep (Rep _ gv))) =+ BeamTable . RowRep . (\hs -> Rep t (repVals (productRep hs)))+ <$> traverse step (zip (toList fv) (toList gv))+ where+ -- The erased-slot coercions: Columnar' f a is a newtype around+ -- Columnar f a, which for a concrete f is f a — so a slot of type+ -- f Any and a Columnar' f Any dictionary have identical runtime+ -- representation. The @a@ is fixed to Any by the rebuild below.+ step (fx, gx) =+ fmap (\(Columnar' hx) -> noInlineUnsafeCo hx :: h Any)+ (combine (noInlineUnsafeCo fx) (noInlineUnsafeCo gx))+ {-# INLINE zipBeamFieldsM #-}++ tblSkeleton =+ BeamTable (RowRep (productRep (replicate (length (fieldNames (Proxy @r))) Ignored)))
+ test/Main.hs view
@@ -0,0 +1,94 @@+{-# LANGUAGE DataKinds #-}+{-# LANGUAGE FlexibleContexts #-}+{-# LANGUAGE ScopedTypeVariables #-}+{-# LANGUAGE TypeApplications #-}+{-# LANGUAGE TypeOperators #-}+{-# OPTIONS_GHC -Wno-orphans #-}++-- | Tests for the polytropos-beam satellite: a 30-column table exercises+-- tblSkeleton, zipBeamFieldsM lockstep traversal, and allBeamValues. The+-- whole suite (and the 30-column table type itself) compiles in a fraction+-- of a second because the Beamable instance never builds a generic+-- representation tree.+module Main (main) where++import Test.Tasty+import Test.Tasty.HUnit+import Data.Functor.Identity (Identity (..))+import Data.Proxy (Proxy (..))+import Database.Beam.Schema.Tables (Beamable (..), Columnar' (..), Ignored,+ allBeamValues, tableValuesNeeded)+import Polytropos+import Polytropos.Beam+import Polytropos.Core (RowRep (..), productRep)+import Unsafe.Coerce (unsafeCoerce)++type Row30 =+ '[ "c00" ':= Int, "c01" ':= Int, "c02" ':= Int, "c03" ':= Int, "c04" ':= Int+ , "c05" ':= Int, "c06" ':= Int, "c07" ':= Int, "c08" ':= Int, "c09" ':= Int+ , "c10" ':= Int, "c11" ':= Int, "c12" ':= Int, "c13" ':= Int, "c14" ':= Int+ , "c15" ':= Int, "c16" ':= Int, "c17" ':= Int, "c18" ':= Int, "c19" ':= Int+ , "c20" ':= Int, "c21" ':= Int, "c22" ':= Int, "c23" ':= Int, "c24" ':= Int+ , "c25" ':= Int, "c26" ':= Int, "c27" ':= Int, "c28" ':= Int, "c29" ':= Int+ ]++-- | Pair column functor for the lockstep-zip test.+newtype PairF x = PairF (x, x)++mkTable :: [Int] -> BeamTable Row30 Identity+mkTable vs = beamTableOfSlots (map (Identity . unsafeCoerce) vs)++recordOf :: [Int] -> Record Row30+recordOf vs = RowRep (productRep (map (Identity . unsafeCoerce) vs))++main :: IO ()+main = defaultMain $ testGroup "Beam Integration"+ [ testCase "skeleton arity for a 30-column table" $+ tableValuesNeeded (Proxy :: Proxy (BeamTable Row30)) @?= 30+ , testCase "skeleton has 30 slots" $+ length (allBeamValues (\(Columnar' _) -> ())+ (tblSkeleton :: BeamTable Row30 Ignored)) @?= 30+ , testCase "default column names from row symbols" $ do+ let ns = fieldNames (Proxy :: Proxy Row30)+ take 3 ns @?= ["c00", "c01", "c02"]+ last ns @?= "c29"+ length ns @?= 30+ , testCase "zipBeamFieldsM zips in lockstep" $ do+ let t1 = mkTable [0 .. 29]+ t2 = mkTable [100 .. 129]+ zipped :: BeamTable Row30 PairF+ zipped = runIdentity $+ zipBeamFieldsM (\(Columnar' x) (Columnar' y) -> pure (Columnar' (PairF (x, y))))+ t1 t2+ pairs = allBeamValues (\(Columnar' (PairF (x, y))) ->+ (unsafeCoerce x :: Int, unsafeCoerce y :: Int))+ zipped+ pairs @?= zip [0 .. 29] [100 .. 129]+ , testCase "zipBeamFieldsM picks the left table" $ do+ let t1 = mkTable [0 .. 29]+ t2 = mkTable [100 .. 129]+ out :: BeamTable Row30 Identity+ out = runIdentity $+ zipBeamFieldsM (\(Columnar' x) (Columnar' _) -> pure (Columnar' x)) t1 t2+ vals = allBeamValues (\(Columnar' x) -> unsafeCoerce x :: Int) out+ vals @?= [0 .. 29]+ , testCase "allBeamValues roundtrips through a record" $ do+ let rec30 = recordOf ([7, 14, 21, 28] ++ replicate 26 (0 :: Int))+ vals = allBeamValues (\(Columnar' x) -> unsafeCoerce x :: Int)+ (toBeamTable rec30)+ vals @?= (7 : 14 : 21 : 28 : replicate 26 (0 :: Int))+ fromBeamTable (toBeamTable rec30) `seq` () @?= ()+ , testCase "beam table constructed with REC and updated with REC_UPD" $ do+ let u1 :: Record '[ "id" ':= Int, "username" ':= String ]+ u1 = REC { id = 1, username = "Alice" }+ u2 = REC_UPD u1 { username = "Bob" }+ tbl = toBeamTable u2+ vals = allBeamValues (\(Columnar' _) -> ()) tbl+ length vals @?= 2+ fromBeamTable tbl @?= u2+ , testCase "HKD record updated with REC_UPD_F" $ do+ let p1 :: RecordF Maybe '[ "id" ':= Maybe Int, "username" ':= Maybe String ]+ p1 = REC_F { id = Just 1, username = Nothing }+ p2 = REC_UPD_F p1 { username = Just "Bob" }+ p2 @?= REC_F { id = Just 1, username = Just "Bob" }+ ]