Lua.Ersatz.Functions

Ersatz functions for Lua API items which may, directly or indirectly, throw a Lua error.

Documentation

hslua_arith

Arguments

:: State

-> ArithOPCode

op

-> Ptr StatusCode

-> IO ()

Performs an arithmetic or bitwise operation over the two values (or one, in the case of negations) at the top of the stack, with the value at the top being the second operand, pops these values, and pushes the result of the operation. The function follows the semantics of the corresponding Lua operator (that is, it may call metamethods).

The value of op must be one of the following constants:

• LUA_OPADD: performs addition (+)
• LUA_OPSUB: performs subtraction (-)
• LUA_OPMUL: performs multiplication (*)
• LUA_OPDIV: performs float division (/)
• LUA_OPIDIV: performs floor division (//)
• LUA_OPMOD: performs modulo (%)
• LUA_OPPOW: performs exponentiation (^)
• LUA_OPUNM: performs mathematical negation (unary -)
• LUA_OPBNOT: performs bitwise NOT (~)
• LUA_OPBAND: performs bitwise AND (&)
• LUA_OPBOR: performs bitwise OR (|)
• LUA_OPBXOR: performs bitwise exclusive OR (~)
• LUA_OPSHL: performs left shift (<<)
• LUA_OPSHR: performs right shift (>>)

This function wraps lua_arith and takes an additional parameter status; if it is not NULL, then the return value is set to the status after calling lua_arith.

hslua_compare

Arguments

:: State

-> StackIndex

index 1

-> StackIndex

index 2

-> OPCode

operator

-> Ptr StatusCode

status

-> IO LuaBool

Compares two Lua values. Returns 1 if the value at index index1 satisfies op when compared with the value at index index2, following the semantics of the corresponding Lua operator (that is, it may call metamethods). Otherwise returns 0. Also returns 0 if any of the indices is not valid.

The value of op must be one of the following constants:

• LUA_OPEQ: compares for equality (==)
• LUA_OPLT: compares for less than (<)
• LUA_OPLE: compares for less or equal (<=)

This function wraps lua_compare and takes an additional parameter status; if it is not NULL, then the return value is set to the status after calling lua_compare.

Get functions (Lua -> stack)

hslua_gettable :: State -> StackIndex -> Ptr StatusCode -> IO TypeCode

Behaves like lua_gettable, but prevents unrecoverable program crashes by calling that function through lua_pcall. Takes an additional status code pointer that is set to the status returned by lua_pcall.

hslua_getglobal :: State -> CString -> CSize -> Ptr StatusCode -> IO TypeCode

Behaves like lua_getglobal, but prevents unrecoverable program crashes by calling that function through lua_pcall. Takes an additional status code pointer that is set to the status returned by lua_pcall.

Set functions (stack -> Lua)

hslua_settable :: State -> StackIndex -> Ptr StatusCode -> IO ()

Behaves like lua_settable, but prevents unrecoverable program crashes by calling that function through lua_pcall. Takes an additional status code pointer that is set to the status returned by lua_pcall.

hslua_setglobal :: State -> CString -> CSize -> Ptr StatusCode -> IO ()

Behaves like lua_setglobal, but prevents unrecoverable program crashes by calling that function through lua_pcall. Takes an additional status code pointer that is set to the status returned by lua_pcall.

Misc

hslua_error :: State -> IO NumResults

Replacement for lua_error; it uses the HsLua error signaling convention instead of raw Lua errors.

hslua_next :: State -> StackIndex -> Ptr StatusCode -> IO LuaBool

Wrapper around lua_next which catches any Lua errors.

hslua_concat :: State -> NumArgs -> Ptr StatusCode -> IO ()

Wrapper around lua_concat which catches any Lua errors.