Foreign.Lua.Util

HsLua utility functions.

Documentation

getglobal' :: String -> Lua ()

Like getglobal, but knows about packages and nested tables. E.g.

getglobal' "math.sin"

will return the function sin in package math.

setglobal' :: String -> Lua ()

Like setglobal, but knows about packages and nested tables. E.g.

pushstring "0.9.4"
setglobal' "mypackage.version"

All tables and fields, except for the last field, must exist.

run :: Lua a -> IO a

Run Lua computation using the default HsLua state as starting point. Exceptions are masked, thus avoiding some issues when using multiple threads. All exceptions are passed through; error handling is the responsibility of the caller.

run' :: ErrorConversion -> Lua a -> IO a

Run Lua computation using the default HsLua state as starting point. Conversion from Lua errors to Haskell exceptions can be controlled through ErrorConversion.

runEither :: Exception e => Lua a -> IO (Either e a)

Run the given Lua computation; exceptions raised in haskell code are caught, but other exceptions (user exceptions raised in haskell, unchecked type errors, etc.) are passed through.

raiseError :: Pushable a => a -> Lua NumResults

Raise a Lua error, using the given value as the error object.

newtype Optional a

Newtype wrapper intended to be used for optional Lua values. Nesting this type is strongly discouraged as missing values on inner levels are indistinguishable from missing values on an outer level; wrong values would be the likely result.

Constructors

Optional

Fields

• fromOptional :: Maybe a

Instances

Pushable a => Pushable (Optional a)

Defined in Foreign.Lua.Util

Methods

push :: Optional a -> Lua ()

Peekable a => Peekable (Optional a)

Defined in Foreign.Lua.Util

Methods

peek :: StackIndex -> Lua (Optional a)

Default error handling

runWith :: State -> Lua a -> IO a

Run Lua computation with the given Lua state and the default error-to-exception converter. Exception handling is left to the caller.

getting values

peekEither :: Peekable a => StackIndex -> Lua (Either String a)

Try to convert the value at the given stack index to a Haskell value. Returns Left with an error message on failure.

WARNING: this is not save to use with custom error handling!

peekRead :: Read a => StackIndex -> Lua a

Get a value by retrieving a String from Lua, then using readMaybe to convert the String into a Haskell value.

popValue :: Peekable a => Lua a

Get, then pop the value at the top of the stack. The pop operation is executed even if the retrieval operation failed.