Foreign.Lua.Peek

Functions which unmarshal and retrieve Haskell values from Lua's stack.

Documentation

type Peeker a = StackIndex -> Lua (Either PeekError a)

Function to retrieve a value from Lua's stack.

newtype PeekError

List of errors which occurred while retrieving a value from the stack.

Constructors

PeekError

Fields

• fromPeekError :: NonEmpty Text

Instances

Eq PeekError

Defined in Foreign.Lua.Peek

Methods

(==) :: PeekError -> PeekError -> Bool

(/=) :: PeekError -> PeekError -> Bool

Show PeekError

Defined in Foreign.Lua.Peek

Methods

showsPrec :: Int -> PeekError -> ShowS

show :: PeekError -> String

showList :: [PeekError] -> ShowS

errorMsg :: Text -> PeekError

Create a peek error from an error message.

force :: Either PeekError a -> Lua a

Force creation of a result, throwing an exception if that's not possible.

formatPeekError :: PeekError -> String

pushMsg :: Text -> PeekError -> PeekError

Add a message to the peek traceback stack.

toPeeker :: (StackIndex -> Lua a) -> Peeker a

Convert an old peek funtion to a Peeker.

Primitives

peekBool :: Peeker Bool

Retrieves a Bool as a Lua boolean.

peekIntegral :: (Integral a, Read a) => Peeker a

Retrieves an Integral value from the Lua stack.

peekRealFloat :: (RealFloat a, Read a) => Peeker a

Retrieve a RealFloat (e.g., Float or Double) from the stack.

Strings

peekByteString :: Peeker ByteString

Retrieves a ByteString as a raw string.

peekLazyByteString :: Peeker ByteString

Retrieves a lazy ByteString as a raw string.

peekString :: Peeker String

Retrieves a String from an UTF-8 encoded Lua string.

peekText :: Peeker Text

Retrieves a Text value as an UTF-8 encoded string.

peekStringy :: IsString a => Peeker a

Retrieves a String-like value from an UTF-8 encoded Lua string.

This should not be used to peek ByteString values or other values for which construction via fromString can result in loss of information.

Collections

peekKeyValuePairs :: Peeker a -> Peeker b -> Peeker [(a, b)]

Read a table into a list of pairs.

peekList :: Peeker a -> Peeker [a]

Reads a numerically indexed table t into a list, where the length of the list is equal to #t. The operation will fail if a numerical field n with 1 ≤ n < #t is missing.

peekMap :: Ord a => Peeker a -> Peeker b -> Peeker (Map a b)

Retrieves a key-value Lua table as Map.

peekSet :: Ord a => Peeker a -> Peeker (Set a)

Retrieves a Set from an idiomatic Lua representation. A set in Lua is idiomatically represented as a table with the elements as keys. Elements with falsy values are omitted.

Combinators

optional

Arguments

:: Peeker a

peeker

-> Peeker (Maybe a)

Makes a result optional. Returns Nothing if the Lua value is nil; otherwise applies the peeker and returns its result.