Re: Shorthand for appending to a table (was Re: 5.2 feature list?)

[Andreas Stenius <kaos@...>]

Luiz Henrique de Figueiredo skrev:
> "t[] = value" as sugar for "t[#t+1]" can be easily done with token filters.
> at least if t is a single name, not a full expression. --lhf

Very true.
Wrote this in 5 minutes.

Example (from a live session, meaning I've actually tested this, at 
least once ;) :

> t = { "foo", "bar" }
> t[]="foobar"
> for k, v in ipairs(t) do print(k, v) end
1       foo
2       bar
3       foobar
>

t can be any *single* <name> token. Source is attached.
Requires dsilvers token filter patch.

//Andreas

-- syntactic sugar for LongTableName[] = value => LongTableName[#LongTableName + 1] = value

local function table_append_sugar(src)
	return function(get,put)
		put("table_append init") -- Eaten during the pipe setup
		local name
		while true do
			local line, tok, val = get()
			put( line, tok, val )
			if tok == "<name>" then
				name = val
			elseif tok == "[" then
				local line2, tok2, val2 = get()
				if line == line2 and tok2 == "]" then
					put( line, "#", nil )
					put( line, "<name>", name )
					put( line, "+", nil )
					put( line, "<number>", 1 )
				end
				put( line2, tok2, val2 )
			end
		end
	end
end

local function pipe(f,get,put)
   put = put or coroutine.yield
   local F=coroutine.wrap(f)
   F(get,put)
   return F
end


local pipeline

local getter
function _TOKEN_PUMP(_getter, source)
   if _getter then
      getter = _getter
      pipeline = pipe(table_append_sugar(source), getter)
   else
      return pipeline()
   end
end