Re: DSL in lua
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- Subject: Re: DSL in lua
- From: Vasiliy Tolstov <v.tolstov@...>
- Date: Thu, 6 Dec 2012 12:19:37 +0400
Big thanks!
But if that possible to avoid using = and not to create many function
like function owner/mode/group etc?
function dump(o)
if type(o) == 'table' then
local s = '{ '
for k,v in pairs(o) do
if type(k) ~= 'string' then k = '"'..k..'"' end
s = s .. ''..k..' = \'' .. dump(v) .. '\', '
end
return s .. '} '
else
return tostring(o)
end
end
function directory(name)
local t = {name=name}
return function (spec)
for key,value in pairs(spec) do
t[key] = value
end
print(dump(t))
-- create_directory(t) ---> actually makes the directory
end
end
directory "/etc" {
path = "/etc";
owner = "root";
group = "wheel";
mode = "0755";
}
2012年12月6日 steve donovan <steve.j.donovan@gmail.com>:
> On Thu, Dec 6, 2012 at 8:53 AM, Vasiliy Tolstov <v.tolstov@selfip.ru> wrote:
>> 1-2) can you provide me simple exmple, please.
>
> function directory(path)
> local t = {path=path}
> return function (spec)
> for key,value in pairs(spec) do
> t[key] = value
> end
> create_directory(t) ---> actually makes the directory
> end
> end
>
> So it's a function that returnsa function - or more accurately creates
> a closure that has a reference to the local t (an 'upvalue')
>
> If we had "directory '/tmp/foo' { owner='root' }" then
> create_directory will be called with the table
> {path='/tmp/foo',owner='root'}
>
> steve d.
>
--
Vasiliy Tolstov,
Clodo.ru
e-mail: v.tolstov@selfip.ru
jabber: vase@selfip.ru