Fix some formatting errors, improve comments.

src/PostgREST/Plan.hs

@@ -118,9 +118,9 @@ resolveTableField :: Table -> Field -> CoercibleField
 resolveTableField table (fieldName, []) = resolveTableFieldName table fieldName
 -- If the field is known and a JSON path is given, always assume the JSON type. But don't assume a type for entirely unknown fields.
 resolveTableField table (fieldName, jp) =
-    case resolveTableFieldName table fieldName of
-      tf@CoercibleField{tfIRType=""} -> tf{tfJsonPath=jp}
-      tf -> tf{tfJsonPath=jp, tfIRType="json"}
+  case resolveTableFieldName table fieldName of
+    tf@CoercibleField{tfIRType=""} -> tf{tfJsonPath=jp}
+    tf -> tf{tfJsonPath=jp, tfIRType="json"}
 
 -- | Resolve a type within the context based on the given field name and JSON path. Although there are situations where failure to resolve a field is considered an error (see `resolveOrError`), there are also situations where we allow it (RPC calls). If it should be an error and `resolveOrError` doesn't fit, ensure to check the `tfIRType` isn't empty.
 resolveTypeOrUnknown :: ResolverContext -> Field -> CoercibleField
@@ -172,12 +172,12 @@ readPlan qi@QualifiedIdentifier{..} AppConfig{configDbMaxRows} SchemaCache{dbTab
     validateSpreadEmbeds =<<
     addRelatedOrders =<<
     addRels qiSchema (iAction apiRequest) dbRelationships Nothing =<<
-      addLogicTrees ctx apiRequest =<<
+    addLogicTrees ctx apiRequest =<<
     addRanges apiRequest =<<
     addOrders apiRequest =<<
     addDataRepresentationAliases =<<
-      expandStarsForDataRepresentations ctx =<<
-      addFilters ctx apiRequest (initReadRequest ctx $ QueryParams.qsSelect $ iQueryParams apiRequest)
+    expandStarsForDataRepresentations ctx =<<
+    addFilters ctx apiRequest (initReadRequest ctx $ QueryParams.qsSelect $ iQueryParams apiRequest)
 
 -- Build the initial read plan tree
 initReadRequest :: ResolverContext -> [Tree SelectItem] -> ReadPlanTree
@@ -525,12 +525,12 @@ mutatePlan mutation qi ApiRequest{..} SchemaCache{dbTables, dbRepresentations} r
       if iPreferRepresentation == None
         then []
         else inferColsEmbedNeeds readReq pkCols
-    pkCols = maybe mempty tablePKCols $ HM.lookup qi dbTables
+    tbl = HM.lookup qi dbTables
+    pkCols = maybe mempty tablePKCols tbl
     logic = map (resolveLogicTree ctx . snd) qsLogic
     rootOrder = maybe [] snd $ find (\(x, _) -> null x) qsOrder
     combinedLogic = foldr (addFilterToLogicForest . resolveFilter ctx) logic qsFiltersRoot
     body = payRaw <$> iPayload -- the body is assumed to be json at this stage(ApiRequest validates)
-    tbl = HM.lookup qi dbTables
     typedColumnsOrError = resolveOrError ctx tbl `traverse` S.toList iColumns
 
 resolveOrError :: ResolverContext -> Maybe Table -> FieldName -> Either ApiRequestError CoercibleField

src/PostgREST/SchemaCache.hs

@@ -156,7 +156,7 @@ removeInternal schemas dbStruct =
     , dbRelationships   = filter (\r -> qiSchema (relForeignTable r) `elem` schemas && not (hasInternalJunction r)) <$>
                         HM.filterWithKey (\(QualifiedIdentifier sch _, _) _ -> sch `elem` schemas ) (dbRelationships dbStruct)
     , dbProcs           = dbProcs dbStruct -- procs are only obtained from the exposed schemas, no need to filter them.
-    , dbRepresentations = dbRepresentations dbStruct -- it's expected to use internal schemas for casting functions; we don't expose these functions through the API, we only use them
+    , dbRepresentations = dbRepresentations dbStruct -- no need to filter, not directly exposed through the API
     }
   where
     hasInternalJunction ComputedRelationship{} = False
@@ -296,21 +296,21 @@ dataRepresentations = SQL.Statement sql (arrayParam HE.text) decodeRepresentatio
   where
     sql = [q|
     SELECT
-         c.castsource::regtype::text,
-         c.casttarget::regtype::text,
-         c.castfunc::regproc::text
+      c.castsource::regtype::text,
+      c.casttarget::regtype::text,
+      c.castfunc::regproc::text
     FROM
       pg_catalog.pg_cast c
     JOIN pg_catalog.pg_type src_t
-        ON c.castsource::oid = src_t.oid
-      JOIN pg_catalog.pg_type dst_t
-        ON c.casttarget::oid = dst_t.oid
+      ON c.castsource::oid = src_t.oid
+    JOIN pg_catalog.pg_type dst_t
+      ON c.casttarget::oid = dst_t.oid
     WHERE
       c.castcontext = 'i'
       AND c.castmethod = 'f'
       AND has_function_privilege(c.castfunc, 'execute')
       AND ((src_t.typtype = 'd' AND c.casttarget IN ('json'::regtype::oid , 'text'::regtype::oid))
-        OR (dst_t.typtype = 'd' AND c.castsource IN ('json'::regtype::oid , 'text'::regtype::oid)))
+       OR (dst_t.typtype = 'd' AND c.castsource IN ('json'::regtype::oid , 'text'::regtype::oid)))
     |]
 
 allProcs :: PgVersion -> Bool -> SQL.Statement [Schema] ProcsMap

src/PostgREST/SchemaCache/Representations.hs

@@ -12,18 +12,18 @@ import qualified Data.HashMap.Strict as HM
 
 import Protolude
 
--- Supporting information for how to receive and return data in API endpoints. This structure answers questions like:
+-- | Data representations allow user customisation of how to present and receive data through APIs, per field.
+-- This structure is used for the library of available transforms. It answers questions like:
 -- - What function, if any, should be used to present a certain field that's been selected for API output?
 -- - How do we parse incoming data for a certain field type when inserting or updating?
 -- - And similarly, how do we parse textual data in a query string to be used as a filter?
--- In the future it's likely this functionality will be extended to cover the outputs and inputs of procedures for RPC.
+--
 -- Support for outputting special formats like CSV and binary data would fit into the same system.
 data DataRepresentation = DataRepresentation
   { drSourceType :: Text
   , drTargetType :: Text
   , drFunction   :: Text
   } deriving (Eq, Show, Generic, JSON.ToJSON, JSON.FromJSON)
 
--- The representation map maps from (source type, target type) to a DR. The absence of a pair here means use the default
--- PostgreSQL type conversion.
+-- The representation map maps from (source type, target type) to a DR.
 type RepresentationsMap = HM.HashMap (Text, Text) DataRepresentation