Construction of function pipeline wrapper in runtime
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- Subject: Construction of function pipeline wrapper in runtime
- From: "Alexander Gladysh" <agladysh@...>
- Date: 2006年6月29日 21:03:19 +0400
Hi, all!
Lua 5.1.
Sometimes I need to write a function like this:
foo = function(a1)
return function(a2)
print(a1, a2.data)
end
end
This is useful when creating small DSLs with entries like this:
foo "name" { data = 123 }
Nesting of this functions is usually 2-3 levels. Also I found useful
to validate argument types in this functions. I use pipeline-generator
function:
name_data = function(sink)
assert(type(sink) == "function")
return function(name)
assert(type(name) == "string")
return function(data)
assert(type(data) == "table")
return sink(name, data)
end
end
end
So I can write more readable function definition:
foo = name_data(function(name, data)
print(name, data.123)
end)
But I need many pipeline-generation functions, for different types and
number of arguments. Is there a way to build them in runtime? There
are no strict limitations on wrapper (like name_data) creation-time
overhead, but call overhead on the wrapped function (foo in this case)
should be minimal.
There is obvious solution:
make_wrapper = function(types)
local n = #types
for i = 1, n do
end
end