Thoughts wanted on automatically "wrapping" existing functions.
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- Subject: Thoughts wanted on automatically "wrapping" existing functions.
- From: Matthew Burke <matthew@...>
- Date: 2020年4月18日 07:24:09 -0400
First a little background:
I often use Lua-GD because in many cases, I find it easier to create an
image by writing code than to try and draw it.
Recently I came up with an idea to make the process a little more
interactive, and to type less. I've tried it out with just a small
handful of the functions and I like how it's shaping up.
Here's the essence of the idea:
gd = require 'gd'
local _img
local _file = os.tmpname()
function show()
_img:png(_file)
os.execute('open -a Preview ' .. _file)
end
function create(sx, sy)
_img = gd.create(sx, sy)
--
-- some code to create a set of colors...
---
end
function setpixel(x, y, c)
local result = _img:setPixel(x, y, c)
show()
return result
end
function rectangle(x1, y1, x2, y2, c)
local result = _img:rectangle(x1, y1, x2, y2, c)
show()
return result
end
-- etc, etc
Now for my question:
I could write the "wrapper" functions by hand. There are roughly 130
functions and constants in Lua-GD, so it wouldn't take forever. But I
feel like there's some clever way I'm not seeing to do it more
automatically.
Another possibility is to change the C code that implements the library.
But I'd prefer to leave it intact.
Here are a couple of issues with doing it automatically:
- debug.getInfo tells me that all the functions are vararg so I can't
build a parameter list
- if I build up the wrapped function as a string and then pass it to
load() to create, since _img is local, I get an error about it being nil
when I try and invoke the function.
So I could easily crank this out by hand and already be done. But I'd
like to hear any suggestions on what's a more clever approach.