Merge branch 'develop-core-lowerCamelCase'. Close #457.

**Description**

To comply with our NASA Class D requirements, our code must abide by a style
guide.

This is the third issue pertaining to style changes for conformance with Class
D within `copilot-core`. We focus only on `copilot-core` to limit the size of
the issue.

**Type**

- Management: conformance with new requirement.

**Additional context**

- See issues 332 and 316 for other style changes addressed in `copilot-core`.

**Requester**

- Ivan Perez

**Method to check presence of bug**

The following Dockerfile checks that each of the functions in question have
been deprecated, in which case it prints the message Success:

```
FROM ubuntu:trusty

RUN apt-get update

RUN apt-get install --yes software-properties-common
RUN add-apt-repository ppa:hvr/ghc
RUN apt-get update

RUN apt-get install --yes ghc-8.6.5 cabal-install-2.4
RUN apt-get install --yes libz-dev

ENV PATH=/opt/ghc/8.6.5/bin:/opt/cabal/2.4/bin:$PWD/.cabal-sandbox/bin:$PATH

RUN cabal update
RUN cabal v1-sandbox init
RUN cabal v1-install alex happy
RUN apt-get install --yes git

SHELL ["/bin/bash", "-c"]
CMD git clone $REPO && cd $NAME && git checkout $COMMIT && cd .. \
  && cabal v1-install copilot/copilot-core/ \
  && ! cabal v1-exec -- runhaskell -Wall -Werror=deprecations <<< "import Copilot.Core.Type(typename,Struct); t :: Struct a => a -> String ; t = typename; main :: IO (); main = return ()" \
  && ! cabal v1-exec -- runhaskell -Wall -Werror=deprecations <<< "{-# LANGUAGE DataKinds #-}; import Copilot.Core.Type(tylength, Type); import Copilot.Core.Type.Array(Array); t :: Type (Array 3 Bool) -> Int ; t = tylength; main :: IO (); main = return ()" \
  && ! cabal v1-exec -- runhaskell -Wall -Werror=deprecations <<< "{-# LANGUAGE DataKinds #-}; import Copilot.Core.Type(tysize, Type); import Copilot.Core.Type.Array(Array); t :: Type (Array 3 Bool) -> Int ; t = tysize; main :: IO (); main = return ()" \
  && ! cabal v1-exec -- runhaskell -Wall -Werror=deprecations <<< "import GHC.TypeLits(KnownSymbol); import Copilot.Core.Type(fieldname, Field); t :: KnownSymbol s0 => Field s0 t0 -> String; t = fieldname; main :: IO (); main = return ()" \
  && ! cabal v1-exec -- runhaskell -Wall -Werror=deprecations <<< "import GHC.TypeLits(KnownSymbol); import Copilot.Core.Type(Field, Struct, accessorname); t :: (Struct a0, KnownSymbol s0) => (a0 -> Copilot.Core.Type.Field s0 t0) -> String; t = accessorname; main :: IO (); main = return ()" \
  && ! cabal v1-exec -- runhaskell -Wall -Werror=deprecations <<< "import Copilot.Core.Type.Array(arrayelems); t = arrayelems; main :: IO (); main = return ()" \
  && echo "Success"
```

Command (substitute variables based on new path after merge):
```sh
$ docker run -e "REPO=https://github.com/copilot-language/copilot" -e "NAME=copilot" -e "COMMIT=<commit_hash>" copilot-verify-457
```

**Expected result**

All Copilot Core code conforms to the following rules:

- Variable and function names should be lowerCamelCase.

Running the docker file above prints the message Success, indicating that, for
all functions identified as non-conforming with the style guide, importing them
(and using them) results in an error.

**Solution implemented**

Deprecate `Copilot.Core.Type.typename`, `Copilot.Core.Type.tylength`,
`Copilot.Core.Type.tysize`, `Copilot.Core.Type.fieldname`,
`Copilot.Core.Type.accessorname`, `Copilot.Core.Type.Array.arrayelems`, and
define corresponding functions with lowerCamelCase names.

Update all uses across all of copilot to match the new function names.

**Further notes**

These changes are public facing, they affect functions that are part of the
API. We follow the deprecation policy for them.

In the docker file, we have to use the functions or GHC will not actually
report an error. In some cases, using them, even if just to define a synonym
for them (one of the simplest ways to use them), requires substantial
boilerplate (signatures, additional imports, extensions, etc).

copilot-c99/CHANGELOG

@@ -1,3 +1,6 @@
+2023-11-05
+        * Replace uses of deprecated functions. (#457)
+
 2023-09-07
         * Version bump (3.16.1). (#455)
         * Clean code. (#453)

copilot-c99/src/Copilot/Compile/C99/CodeGen.hs

@@ -33,7 +33,7 @@ import qualified Language.C99.Simple as C
 
 -- Internal imports: Copilot
 import Copilot.Core ( Expr (..), Id, Stream (..), Struct (..), Trigger (..),
-                      Type (..), UExpr (..), Value (..), fieldname, tysize )
+                      Type (..), UExpr (..), Value (..), fieldName, typeSize )
 
 -- Internal imports
 import Copilot.Compile.C99.Error    ( impossible )
@@ -67,17 +67,17 @@ mkExtCpyDecln (External _name cpyName ty) = decln
 mkStructDecln :: Struct a => Type a -> C.Decln
 mkStructDecln (Struct x) = C.TypeDecln struct
   where
-    struct = C.TypeSpec $ C.StructDecln (Just $ typename x) fields
+    struct = C.TypeSpec $ C.StructDecln (Just $ typeName x) fields
     fields = NonEmpty.fromList $ map mkField (toValues x)
 
     mkField :: Value a -> C.FieldDecln
-    mkField (Value ty field) = C.FieldDecln (transType ty) (fieldname field)
+    mkField (Value ty field) = C.FieldDecln (transType ty) (fieldName field)
 
 -- | Write a forward struct declaration.
 mkStructForwDecln :: Struct a => Type a -> C.Decln
 mkStructForwDecln (Struct x) = C.TypeDecln struct
   where
-    struct = C.TypeSpec $ C.Struct (typename x)
+    struct = C.TypeSpec $ C.Struct (typeName x)
 
 -- * Ring buffers
 
@@ -134,7 +134,7 @@ mkGenFunArray name nameArg expr ty@(Array _) =
 
     -- Copy expression to output argument
     stmts = [ C.Expr $ memcpy (C.Ident nameArg) cExpr size ]
-    size  = C.LitInt (fromIntegral $ tysize ty)
+    size  = C.LitInt (fromIntegral $ typeSize ty)
               C..* C.SizeOfType (C.TypeName $ tyElemName ty)
 
 mkGenFunArray _name _nameArg _expr _ty =
@@ -180,7 +180,7 @@ mkStep cSettings streams triggers exts =
               where
                 dest = C.Index buffVar indexVar
                 size = C.LitInt
-                           (fromIntegral $ tysize ty)
+                           (fromIntegral $ typeSize ty)
                            C..* C.SizeOfType (C.TypeName (tyElemName ty))
             _       -> C.Expr $
                            C.Index buffVar indexVar C..= C.Ident tmpVar
@@ -203,7 +203,7 @@ mkStep cSettings streams triggers exts =
         where
           exVar  = C.Ident cpyName
           locVar = C.Ident name
-          size   = C.LitInt (fromIntegral $ tysize ty)
+          size   = C.LitInt (fromIntegral $ typeSize ty)
                      C..* C.SizeOfType (C.TypeName (tyElemName ty))
 
       _       -> C.Ident cpyName C..= C.Ident name

copilot-c99/src/Copilot/Compile/C99/Expr.hs

@@ -14,7 +14,7 @@ import qualified Language.C99.Simple as C
 
 -- Internal imports: Copilot
 import Copilot.Core ( Expr (..), Field (..), Op1 (..), Op2 (..), Op3 (..),
-                      Type (..), Value (..), accessorname, arrayelems,
+                      Type (..), Value (..), accessorName, arrayElems,
                       toValues )
 
 -- Internal imports
@@ -96,7 +96,7 @@ transOp1 op e =
     Floor    ty   -> funCall (specializeMathFunName ty "floor") [e]
     BwNot    _    -> (C..~) e
     Cast     _ ty -> C.Cast (transTypeName ty) e
-    GetField (Struct _)  _ f -> C.Dot e (accessorname f)
+    GetField (Struct _)  _ f -> C.Dot e (accessorName f)
 
 -- | Translates a Copilot binary operator and its arguments into a C99
 -- expression.
@@ -239,7 +239,7 @@ constTy ty = case ty of
   Float     -> explicitTy ty . C.LitFloat
   Double    -> explicitTy ty . C.LitDouble
   Struct _  -> C.InitVal (transTypeName ty) . constStruct . toValues
-  Array ty' -> C.InitVal (transTypeName ty) . constArray ty' . arrayelems
+  Array ty' -> C.InitVal (transTypeName ty) . constArray ty' . arrayElems
 
 -- | Transform a Copilot Core literal, based on its value and type, into a C99
 -- initializer.
@@ -265,7 +265,7 @@ constInit ty val = case ty of
   -- whole expression as an array of two int32_t's (as opposed to a nested
   -- array). This can either lead to compile-time errors (if you're lucky) or
   -- incorrect runtime semantics (if you're unlucky).
-  Array ty' -> C.InitList $ constArray ty' $ arrayelems val
+  Array ty' -> C.InitList $ constArray ty' $ arrayElems val
 
   -- We use InitArray to initialize a struct because the syntax used for
   -- initializing arrays and structs is compatible. For instance, {1, 2} works

copilot-c99/src/Copilot/Compile/C99/Type.hs

@@ -12,7 +12,7 @@ module Copilot.Compile.C99.Type
 import qualified Language.C99.Simple as C
 
 -- Internal imports: Copilot
-import Copilot.Core ( Type (..), tylength, typename )
+import Copilot.Core ( Type (..), typeLength, typeName )
 
 -- | Translate a Copilot type to a C99 type.
 transType :: Type a -> C.Type
@@ -30,8 +30,8 @@ transType ty = case ty of
   Double    -> C.TypeSpec C.Double
   Array ty' -> C.Array (transType ty') len
     where
-      len = Just $ C.LitInt $ fromIntegral $ tylength ty
-  Struct s  -> C.TypeSpec $ C.Struct (typename s)
+      len = Just $ C.LitInt $ fromIntegral $ typeLength ty
+  Struct s  -> C.TypeSpec $ C.Struct (typeName s)
 
 -- | Translate a Copilot type to a valid (local) variable declaration C99 type.
 --

copilot-c99/tests/Test/Copilot/Compile/C99.hs

@@ -279,7 +279,7 @@ arbitraryArrayIx :: forall t n . (Typed t, KnownNat n, Num t)
                         , [Array n t] -> [Word32] -> [t]
                         )
 arbitraryArrayIx = return
-  (Op2 (Index typeOf), zipWith (\x y -> arrayelems x !! fromIntegral y))
+  (Op2 (Index typeOf), zipWith (\x y -> arrayElems x !! fromIntegral y))
 
 -- | Generator of functions on Floating point numbers.
 arbitraryOpFloat :: (Floating t, Typed t) => Gen (Fun t t, [t] -> [t])
@@ -860,7 +860,7 @@ varDeclC Word64       v = "uint64_t " ++ v
 varDeclC Float        v = "float " ++ v
 varDeclC Double       v = "double " ++ v
 varDeclC t@(Array tE) v =
-  typeC tE ++ " " ++ v ++ "[" ++ show (tylength t) ++ "]"
+  typeC tE ++ " " ++ v ++ "[" ++ show (typeLength t) ++ "]"
 varDeclC _            _ = error
   "copilot-c99 (test): Input variables of type struct are not yet supported."
 
@@ -877,7 +877,7 @@ sizeC Word32       = "sizeof(uint32_t)"
 sizeC Word64       = "sizeof(uint64_t)"
 sizeC Float        = "sizeof(float)"
 sizeC Double       = "sizeof(double)"
-sizeC t@(Array tE) = show (tylength t) ++ "* sizeof(" ++ typeC tE ++ ")"
+sizeC t@(Array tE) = show (typeLength t) ++ "* sizeof(" ++ typeC tE ++ ")"
 sizeC _            = error
   "copilot-c99 (test): Input variables of type struct are not yet supported."
 
@@ -920,7 +920,7 @@ instance CShow Bool where
   cshow False = "false"
 
 instance CShow t => CShow (Array n t) where
-  cshow a = intercalate "," $ map cshow $ arrayelems a
+  cshow a = intercalate "," $ map cshow $ arrayElems a
 
 -- | Read a value of a given type in C.
 class ReadableFromC a where

copilot-core/CHANGELOG

@@ -1,3 +1,6 @@
+2023-11-05
+        * Compliance with style guide. (#457)
+
 2023-09-07
         * Version bump (3.16.1). (#455)
 

copilot-core/src/Copilot/Core/Type.hs

@@ -23,16 +23,21 @@ module Copilot.Core.Type
     , UType (..)
     , SimpleType (..)
 
+    , typeSize
     , tysize
+    , typeLength
     , tylength
 
     , Value (..)
     , toValues
     , Field (..)
+    , typeName
     , typename
 
     , Struct
+    , fieldName
     , fieldname
+    , accessorName
     , accessorname
     )
   where
@@ -50,11 +55,19 @@ import GHC.TypeLits       (KnownNat, KnownSymbol, Symbol, natVal, sameNat,
 -- Internal imports
 import Copilot.Core.Type.Array (Array)
 
+{-# DEPRECATED typename "Use typeName instead." #-}
+
 -- | The value of that is a product or struct, defined as a constructor with
 -- several fields.
 class Struct a where
+  -- | Returns the name of struct in the target language.
+  typeName :: a -> String
+  typeName = typename
+
   -- | Returns the name of struct in the target language.
   typename :: a -> String
+  typename = typeName
+
   -- | Transforms all the struct's fields into a list of values.
   toValues :: a -> [Value a]
 
@@ -66,18 +79,30 @@ data Value a =
 -- level.
 data Field (s :: Symbol) t = Field t
 
+-- | Extract the name of a field.
+fieldName :: forall s t . KnownSymbol s => Field s t -> String
+fieldName _ = symbolVal (Proxy :: Proxy s)
+
+{-# DEPRECATED fieldname "Use fieldName instead." #-}
 -- | Extract the name of a field.
 fieldname :: forall s t . KnownSymbol s => Field s t -> String
-fieldname _ = symbolVal (Proxy :: Proxy s)
+fieldname = fieldName
+
+-- | Extract the name of an accessor (a function that returns a field of a
+-- struct).
+accessorName :: forall a s t . (Struct a, KnownSymbol s)
+             => (a -> Field s t) -> String
+accessorName _ = symbolVal (Proxy :: Proxy s)
 
+{-# DEPRECATED accessorname "Use accessorName instead." #-}
 -- | Extract the name of an accessor (a function that returns a field of a
 -- struct).
 accessorname :: forall a s t . (Struct a, KnownSymbol s)
              => (a -> Field s t) -> String
-accessorname _ = symbolVal (Proxy :: Proxy s)
+accessorname = accessorName
 
 instance (KnownSymbol s, Show t) => Show (Field s t) where
-  show f@(Field v) = fieldname f ++ ":" ++ show v
+  show f@(Field v) = fieldName f ++ ":" ++ show v
 
 instance {-# OVERLAPPABLE #-} (Typed t, Struct t) => Show t where
   show t = "<" ++ fields ++ ">"
@@ -108,14 +133,24 @@ data Type :: * -> * where
                          ) => Type t -> Type (Array n t)
   Struct :: (Typed a, Struct a) => a -> Type a
 
+-- | Return the length of an array from its type
+typeLength :: forall n t . KnownNat n => Type (Array n t) -> Int
+typeLength _ = fromIntegral $ natVal (Proxy :: Proxy n)
+
+{-# DEPRECATED tylength "Use typeLength instead." #-}
 -- | Return the length of an array from its type
 tylength :: forall n t . KnownNat n => Type (Array n t) -> Int
-tylength _ = fromIntegral $ natVal (Proxy :: Proxy n)
+tylength = typeLength
+
+-- | Return the total (nested) size of an array from its type
+typeSize :: forall n t . KnownNat n => Type (Array n t) -> Int
+typeSize ty@(Array ty'@(Array _)) = typeLength ty * typeSize ty'
+typeSize ty@(Array _            ) = typeLength ty
 
+{-# DEPRECATED tysize "Use typeSize instead." #-}
 -- | Return the total (nested) size of an array from its type
 tysize :: forall n t . KnownNat n => Type (Array n t) -> Int
-tysize ty@(Array ty'@(Array _)) = tylength ty * tysize ty'
-tysize ty@(Array _            ) = tylength ty
+tysize = typeSize
 
 instance TestEquality Type where
   testEquality Bool   Bool   = Just DE.Refl

copilot-core/src/Copilot/Core/Type/Array.hs

@@ -13,6 +13,7 @@
 module Copilot.Core.Type.Array
     ( Array
     , array
+    , arrayElems
     , arrayelems
     )
   where
@@ -39,6 +40,11 @@ array xs | datalen == typelen = Array xs
     errmsg = "Length of data (" ++ show datalen ++
              ") does not match length of type (" ++ show typelen ++ ")."
 
+-- | Return the elements of an array.
+arrayElems :: Array n a -> [a]
+arrayElems (Array xs) = xs
+
+{-# DEPRECATED arrayelems "Use ArrayElems instead." #-}
 -- | Return the elemts of an array.
 arrayelems :: Array n a -> [a]
-arrayelems (Array xs) = xs
+arrayelems = arrayElems

copilot-core/tests/Test/Copilot/Core/Type/Array.hs

@@ -13,7 +13,7 @@ import Test.QuickCheck                      (Gen, Property, arbitrary, forAll,
                                              vectorOf)
 
 -- Internal imports: library modules being tested
-import Copilot.Core.Type.Array (Array, array, arrayelems)
+import Copilot.Core.Type.Array (Array, array, arrayElems)
 
 -- | All unit tests for copilot-core:Copilot.Core.Array.
 tests :: Test.Framework.Test
@@ -30,13 +30,13 @@ tests =
 -- * Individual tests
 
 -- | Test that building an array from a list and extracting the elements with
--- the function 'arrayelems' will result in the same list.
+-- the function 'arrayElems' will result in the same list.
 testArrayElemsLeft :: forall n . KnownNat n => Proxy n -> Property
 testArrayElemsLeft len =
     forAll xsInt64 $ \ls ->
       let array' :: Array n Int64
           array' = array ls
-      in arrayelems array' == ls
+      in arrayElems array' == ls
 
   where
 

copilot-interpreter/CHANGELOG

@@ -1,3 +1,6 @@
+2023-11-05
+        * Replace uses of deprecated functions. (#457)
+
 2023-09-07
         * Version bump (3.16.1). (#455)
 

copilot-interpreter/src/Copilot/Interpret/Eval.hs

@@ -17,7 +17,7 @@ module Copilot.Interpret.Eval
 
 import Copilot.Core            (Expr (..), Field (..), Id, Name, Observer (..),
                                 Op1 (..), Op2 (..), Op3 (..), Spec, Stream (..),
-                                Trigger (..), Type (..), UExpr (..), arrayelems,
+                                Trigger (..), Type (..), UExpr (..), arrayElems,
                                 specObservers, specStreams, specTriggers)
 import Copilot.Interpret.Error (badUsage)
 
@@ -242,7 +242,7 @@ evalOp2 op = case op of
   BwXor _      -> (xor)
   BwShiftL _ _ -> ( \ !a !b -> shiftL a $! fromIntegral b )
   BwShiftR _ _ -> ( \ !a !b -> shiftR a $! fromIntegral b )
-  Index    _   -> \xs n -> (arrayelems xs) !! (fromIntegral n)
+  Index    _   -> \xs n -> (arrayElems xs) !! (fromIntegral n)
 
 -- | Apply a function to two numbers, so long as the second one is
 -- not zero.

copilot-prettyprinter/CHANGELOG

@@ -1,3 +1,6 @@
+2023-11-05
+        * Replace uses of deprecated functions. (#457)
+
 2023-09-07
         * Version bump (3.16.1). (#455)
 

copilot-prettyprinter/src/Copilot/PrettyPrint.hs

@@ -71,7 +71,7 @@ ppOp1 op = case op of
   Floor _                 -> ppPrefix "floor"
   BwNot _                 -> ppPrefix "~"
   Cast _ _                -> ppPrefix "(cast)"
-  GetField (Struct _) _ f -> \e -> ppInfix "#" e (text $ accessorname f)
+  GetField (Struct _) _ f -> \e -> ppInfix "#" e (text $ accessorName f)
   GetField _ _ _          -> impossible "ppOp1" "Copilot.PrettyPrint"
 
 -- | Pretty-print a binary operation.

copilot-theorem/CHANGELOG

@@ -1,5 +1,6 @@
-2023-11-03
+2023-11-05
         * Relax version constraint on what4. (#461)
+        * Replace uses of deprecated functions. (#457)
 
 2023-09-07
         * Version bump (3.16.1). (#455)

copilot-theorem/src/Copilot/Theorem/What4/Translate.hs

@@ -365,7 +365,7 @@ translateConstExpr sym tp a = case tp of
   CT.Float -> XFloat <$> WFP.iFloatLitSingle sym a
   CT.Double -> XDouble <$> WFP.iFloatLitDouble sym a
   CT.Array tp -> do
-    elts <- traverse (translateConstExpr sym tp) (CT.arrayelems a)
+    elts <- traverse (translateConstExpr sym tp) (CT.arrayElems a)
     Some n <- return $ mkNatRepr (genericLength elts)
     case isZeroOrGT1 n of
       Left Refl -> return XEmptyArray

copilot/CHANGELOG

@@ -1,3 +1,6 @@
+2023-11-05
+        * Replace uses of deprecated functions. (#457)
+
 2023-11-03
         * Fix typo in README. (#459)
 

copilot/examples/Structs.hs

@@ -19,7 +19,7 @@ data Volts = Volts
 
 -- | `Struct` instance for `Volts`.
 instance Struct Volts where
-  typename _ = "volts"
+  typeName _ = "volts"
   toValues volts = [ Value Word16 (numVolts volts)
                    , Value Bool   (flag volts)
                    ]
@@ -36,7 +36,7 @@ data Battery = Battery
 
 -- | `Battery` instance for `Struct`.
 instance Struct Battery where
-  typename _ = "battery"
+  typeName _ = "battery"
   toValues battery = [ Value typeOf (temp battery)
                      , Value typeOf (volts battery)
                      , Value typeOf (other battery)