Config.hs

module Hasql.Generate.Config
    ( Config (..)
    ) where

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import           Data.Bool                 ( Bool (..) )
import           Data.Default.Class        ( Default (..) )
import           Data.String               ( String )

import           Hasql.Generate.Connection ( ConnectionInfo, libpqDefaults )

import           Language.Haskell.TH       ( Name )

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{-  Top-level configuration for compile-time code generation.

    Embeds the database connection parameters ('ConnectionInfo') together with
    behavioral flags that control the shape of the generated code.

    Use @def@ for the default configuration, which reads connection details
    from standard PostgreSQL environment variables, sets False to allowDuplicateRecordFields
    and newtypePrimaryKeys, and has an emply override list.
-}
data Config
    = Config
      { connection                 :: ConnectionInfo
      , allowDuplicateRecordFields :: Bool
      , newtypePrimaryKeys         :: Bool
      , globalOverrides            :: [(String, Name)]
      }

{-  Default configuration:

    * Connection via libpq environment variables (@PGHOST@, @PGPORT@, etc.)
    * @allowDuplicateRecordFields = False@ — field names are prefixed with the
      type name so the generated code compiles without @DuplicateRecordFields@
    * @newtypePrimaryKeys = False@ — when @True@, generates newtype (single PK)
      or data record (composite PK) wrappers for primary keys, plus @HasPrimaryKey@
      instances for all tables with PKs
    * @globalOverrides = []@ — PG type overrides applied to all tables. Per-table
      'withOverrides' take precedence over global ones.
-}
instance Default Config where
  def :: Config
  def =
    Config
      { connection = libpqDefaults
      , allowDuplicateRecordFields = False
      , newtypePrimaryKeys = False
      , globalOverrides = []
      }