raze-gles/polymer/eduke32/source/lunatic/control.lua

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-- Game control module for Lunatic.
local ffi = require("ffi")
local setmetatable = setmetatable
local assert = assert
local error = error
local type = type
module(...)
local lastid = { action=0, move=0, ai=0 }
local def = { action={}, move={}, ai={} }
local function forbidden() error("newindex forbidden", 2) end
AC = setmetatable({}, { __index=def.action, __newindex=forbidden })
MV = setmetatable({}, { __index=def.move, __newindex=forbidden })
AI = setmetatable({}, { __index=def.ai, __newindex=forbidden })
local function check_name(name, what, errlev)
if (type(name)~="string" or #name > 63) then
error("bad argument #1 to "..what..": must be a string of length <= 63", errlev+1)
end
end
local function action_or_move(what, numargs, tab, name, ...)
assert(lastid[what] > -(2^31))
check_name(name, what, 3)
local args = {...}
assert(#args <= numargs)
for i=1,#args do
local n = args[i]
if (type(n)~="number" or not (n >= -32768 and n <= 32767)) then
error("bad argument #".. i+1 .." to "..what..
": must be numbers in [-32768..32767]", 3)
end
end
-- missing fields are initialized to 0 by ffi.new
-- Named actions or moves have negative ids so that non-negative ones
-- can be used as (different) placeholders for all-zero ones.
lastid[what] = lastid[what]-1
-- ffi.new takes either for initialization: varargs, a table with numeric
-- indices, or a table with key-value pairs
-- See http://luajit.org/ext_ffi_semantics.html#init_table
tab[name] = ffi.new("const con_"..what.."_t", lastid[what], args)
end
function action(name, ...)
action_or_move("action", 5, def.action, name, ...)
end
function move(name, ...)
action_or_move("move", 2, def.move, name, ...)
end
local function get_action_or_move(what, val, argi)
if (val == nil) then
return {} -- will init the struct to all zeros
elseif (type(val)=="string") then
local am = def[what][val]
if (am==nil) then
error("no "..what.." '"..val.."' defined", 3)
end
return am
elseif (ffi.istype("con_"..what.."_t", val)) then
return val
end
-- TODO: literal number actions/moves?
error("bad argument #"..argi.." to ai: must be string or "..what)
end
function ai(name, action, move, flags)
assert(lastid.ai > -(2^31))
check_name(name, "ai", 2)
lastid.ai = lastid.ai-1
local act = get_action_or_move("action", action, 2)
local mov = get_action_or_move("move", move, 3)
if (flags~=nil) then
if (type(flags)~="number" or not (flags>=0 and flags<=32767)) then
error("bad argument #4 to ai: must be a number in [0..32767]", 2)
end
else
flags = 0
end
def.ai[name] = ffi.new("const con_ai_t", lastid.ai, act, mov, flags)
end