I get an error in the HTML5 bundled application when I call string.format with a table argument after the format string. The table has a __tostring metatmethod so it should convert to a string and it works as expected when running from the editor. But in the bundled application in causes an error as string.format complains about being given a table when expecting a string.
HTML5 use Lua 5.1.4 while all other platforms use LuaJIT. I bet there is some subtle difference where the __tostring metamethod isn’t invoked in this case…
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Yep:
> lua -v
Lua 5.1.5 Copyright (C) 1994-2012 Lua.org, PUC-Rio
> cat foo.lua
local t = setmetatable({}, {
__tostring = function(t, ...)
return "Hello" .. 123
end
})
print(t)
print(string.format("Testing %s", t))%
> lua foo.lua
Hello123
lua: foo.lua:8: bad argument #2 to 'format' (string expected, got table)
stack traceback:
[C]: in function 'format'
foo.lua:8: in main chunk
[C]: ?
2 Likes
I came back to say that I tested it and you are right. Interesting to know…
A quick hack to give better behaviour:
function log(f, ...)
local args = { ... }
for i, v in ipairs(args) do
if type(v) == "table" then
args[i] = tostring(v)
else
args[i] = v
end
end
print(string.format(f, unpack(args)))
end
I do more in my log function but just in case anybody else hits this problem this shows one way to work around it.
1 Like