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-- gen_LuaState_Call.lua
-- Generates the cLuaState::Call() function templates that are included from LuaState.h
--[[
The cLuaState::Call() family of functions provides a template-based system for calling any Lua function
either by name or by reference with almost any number of parameters and return values. This is done by
providing a number of overloads of the same name with variable number of template-type parameters. To
separate the arguments from the return values, a special type of cLuaState::cRet is used.
--]]
print("Generating LuaState_Call.inc . . .")
-- List of combinations (# params, # returns) to generate:
local Combinations =
{
-- no return values:
{0, 0},
{1, 0},
{2, 0},
{3, 0},
{4, 0},
-- 1 return value:
{0, 1},
{1, 1},
{2, 1},
{3, 1},
{4, 1},
{5, 1},
{6, 1},
{7, 1},
{8, 1},
{9, 1},
{10, 1},
-- 2 return values:
{0, 2},
{1, 2},
{2, 2},
{3, 2},
{4, 2},
{5, 2},
{6, 2},
{7, 2},
{8, 2},
{9, 2},
-- Special combinations:
{7, 3},
{8, 3},
{5, 5},
{9, 5},
}
--- Writes a single overloaded function definition for the specified number of params and returns into f
--[[
The format for the generated function is this:
/** Call the specified 3-param 2-return Lua function:
Returns true if call succeeded, false if there was an error. */
template <typename FnT, typename ParamT1, typename ParamT2, typename ParamT3, typename RetT1, typename RetT2>
bool Call(FnT a_Function, ParamT1 a_Param1, ParamT2 a_Param2, ParamT3 a_Param3, const cLuaState::cRet & a_RetMark, RetT1 & a_Ret1, RetT2 & a_Ret2)
{
UNUSED(a_RetMark);
if (!PushFunction(a_Function))
{
return false;
}
Push(a_Param1);
Push(a_Param2);
Push(a_Param3);
if (!CallFunction(2))
{
return false;
}
GetStackValue(-2, a_Ret1);
GetStackValue(-1, a_Ret2);
lua_pop(m_LuaState, 2);
return true;
}
Note especially the negative numbers in GetStackValue() calls.
--]]
local function WriteOverload(f, a_NumParams, a_NumReturns)
-- Write the function doxy-comments:
f:write("/** Call the specified ", a_NumParams, "-param ", a_NumReturns, "-return Lua function:\n")
f:write("Returns true if call succeeded, false if there was an error. */\n")
-- Write the template <...> line:
f:write("template <typename FnT")
for i = 1, a_NumParams do
f:write(", typename ParamT", i)
end
if (a_NumReturns > 0) then
for i = 1, a_NumReturns do
f:write(", typename RetT", i)
end
end
f:write(">\n")
-- Write the function signature:
f:write("bool Call(")
f:write("FnT a_Function")
for i = 1, a_NumParams do
f:write(", ParamT", i, " a_Param", i)
end
if (a_NumReturns > 0) then
f:write(", const cLuaState::cRet & a_RetMark")
for i = 1, a_NumReturns do
f:write(", RetT", i, " & a_Ret", i)
end
end
f:write(")\n")
-- Common code:
f:write("{\n")
if (a_NumReturns > 0) then
f:write("\tUNUSED(a_RetMark);\n")
end
f:write("\tif (!PushFunction(a_Function))\n")
f:write("\t{\n")
f:write("\t\treturn false;\n")
f:write("\t}\n")
-- Push the params:
for i = 1, a_NumParams do
f:write("\tPush(a_Param", i, ");\n")
end
-- Call the function:
f:write("\tif (!CallFunction(", a_NumReturns, "))\n")
f:write("\t{\n")
f:write("\t\treturn false;\n")
f:write("\t}\n")
-- Get the return values:
for i = 1, a_NumReturns do
f:write("\tGetStackValue(", -1 - a_NumReturns + i, ", a_Ret", i, ");\n")
end
-- Pop the returns off the stack, if needed:
if (a_NumReturns > 0) then
f:write("\tlua_pop(m_LuaState, ", a_NumReturns, ");\n")
end
-- Everything ok:
f:write("\treturn true;\n")
f:write("}\n")
-- Separate from the next function:
f:write("\n\n\n\n\n")
end
local f = assert(io.open("LuaState_Call.inc", "w"))
-- Write file header:
f:write([[
// LuaState_Call.inc
// This file is auto-generated by gen_LuaState_Call.lua
// Make changes to the generator instead of to this file!
// This file contains the various overloads for the cLuaState::Call() function
// Each overload handles a different number of parameters / return values
]])
f:write("\n\n\n\n\n")
-- Write out a template function for each overload:
for _, combination in ipairs(Combinations) do
WriteOverload(f, combination[1], combination[2])
end
-- Close the generated file
f:close()
print("LuaState_Call.inc generated.")
|
