Re: Some enhancements in table initializations
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- Subject: Re: Some enhancements in table initializations
- From: David Manura <dm.lua@...>
- Date: 2010年9月21日 01:04:45 -0400
On Mon, Sep 20, 2010 at 11:53 PM, Jonathan Castello <twisolar@gmail.com> wrote:
> On Mon, Sep 20, 2010 at 8:29 PM, Nilson <nilson.brazil@gmail.com> wrote:
>> Proposition 1. Make the separator optional in table initialization
>> Proposition 2. Extending the function name syntactic sugar to tables.
>
> If they're doable, I like these two a lot.
There have been proposals for these before:
http://lua-users.org/lists/lua-l/2003-02/msg00405.html
http://lua-users.org/lists/lua-l/2010-01/msg01405.html
http://lua-users.org/lists/lua-l/2008-02/msg00830.html
http://lua-users.org/lists/lua-l/2010-08/msg00569.html
And personally, I've wanted something like Proposition 1. Lisp and
CMake languages allow this simpler syntax. The major problem it poses
in Lua is that Lua expressions without a commas between them can too
easily run together. {a "" {}} is valid in Lua 5.1, for example. The
problem also occurs with statements without semicolons between them
("ambiguous syntax" error) but with a much lower frequency.
You can simulate a Perl-like "qw" quote operator though:
-- like http://perldoc.perl.org/perlop.html#Quote-Like-Operators
local function qw(s)
local t = {}
for x in s:gmatch("%S+") do
t[#t+1] = x
end
return t
end
t = qw[[ foo bar baz ]]
Unfortunately, you can't easily embed variables, particularly
lexicals, inside these strings. That's a common problem, and more
ideally you'd want Lua to expand qw at the macro/lexical processing
stage rather than at run-time:
http://lua-users.org/wiki/StringInterpolation
>> Proposition 3: Unquoted strings constants
See qw above.