minetest-i4/src/operators.lua
2021-11-30 19:00:47 +01:00

83 lines
1.7 KiB
Lua

--[[ All source files have to be preprocessed before loading.
This allows implementing custom operators like bitwise ones. ]]
local fmt, split = string.format, string.split
local var = "[%w%.%[%]\"\'_]"
local operators = {
["([%+%-%*%^/&|])="] = function(a, b, c)
return fmt("%s = %s %s %s", a, a, b, c)
end,
["+%+"] = function(a, b)
return fmt("%s = %s + 1\n%s", a, a, b)
end,
["&"] = function(a, b)
return fmt("bit.band(%s, %s)", a, b)
end,
["|"] = function(a, b)
return fmt("bit.bor(%s, %s)", a, b)
end,
["<<"] = function(a, b)
return fmt("bit.lshift(%s, %s)", a, b)
end,
[">>"] = function(a, b)
return fmt("bit.rshift(%s, %s)", a, b)
end,
["<<="] = function(a, b)
return fmt("%s = bit.lshift(%s, %s)", a, a, b)
end,
[">>="] = function(a, b)
return fmt("%s = bit.rshift(%s, %s)", a, a, b)
end,
}
local function compile(data)
data = data:gsub("IMPORT%((.-)%)", function(a)
return "local " .. a:gsub("\"", "") .. " = i3.get(" .. a .. ")"
end)
for op, func in pairs(operators) do
data = data:gsub("(" .. var .. "+)%s?" .. op .. "%s?(" .. var .. "*)", func)
end
return data
end
local function _load(path, line, data, t)
if line then
if not t then
t = split(data, "\n")
end
t[line] = t[line]:gsub("(" .. var .. "+)%s?=%s?(" .. var .. "*)", "%2")
data = table.concat(t, "\n")
else
local file = assert(io.open(path, "r"))
data = file:read"*a"
file:close()
data = compile(data)
end
local l, err = loadstring(data)
if not l then
local err_line = tonumber(err:match(":(%d+):"))
if line ~= err_line then
return _load(path, err_line, data, t)
end
end
return l, err
end
return function(path)
return _load(path) or loadfile(path)
end