Re: Proposal for a new construct in Lua
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- Subject: Re: Proposal for a new construct in Lua
- From: Dirk Laurie <dpl@...>
- Date: 2011年5月14日 22:39:24 +0200
On Sat, May 14, 2011 at 07:26:18PM +0200, Michael Rose wrote:
> jump chr = str:byte(i) in 0,255 do
> "a".."z" do print("lower") break end
> "A".."Z" do print("higher") break end
> 32,"_-:" do print("delimiter") break end
> 0 .. 31, 127 .. 255 do print("unprintable") break end
> do print("other") end
> end
1. "a".."z" and 0 .. 31 already have meanings in Lua.
2. 0,255 and 0 .. 255 both seem to mean the range 0 to 255.
3. Comma already has a meaning in Lua.
4. "in" expects an iterator function in Lua.
5. Lua already has a way of writing ranges in a pattern.
6. This syntax is at least as verbose as doing it with if,then,elseif.
If all that "jump" is going to achieve is to make it easier to respond
to different values of a character, I'll stick to Lua 5.2.
match = string.match
if match(chr,"[a-z]") then print("lower")
elseif match(chr,"[A-Z]") then print("upper")
elseif match(chr,"[32円_%-:]") then print("delimiter")
elseif match(chr,"[0円-31円127円-255円]") then print("unprintable")
else print("other")
end
Dirk