Re: Integers-related trap in Lua 5.3
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- Subject: Re: Integers-related trap in Lua 5.3
- From: Philipp Janda <siffiejoe@...>
- Date: 2016年5月16日 16:04:31 +0200
Am 16.05.2016 um 14:34 schröbte Jonne Ransijn:
I don't really like the 1'000'000 syntax,
Me neither.
because I would personally rather be able to add syntax to call a function
like so:
print(sin 45)
-- (x) => expr
-- is the same as:
-- function(x) expr end
That probably should be `function(x) return expr end`.
local add = (x) => (y) => x + y
local con = (x) => (y) => x .. y
local con3 = (x) => (y) => (z) => x .. y .. z
I have written a `curry` function[1] that removes the need for this kind
of line noise:
local con3 = curry( 3, function( x, y, z ) return x .. y .. z end )
print(add 21 21)
print(con 'Hello, ' 7)
print(con3 1 '000' 000) -- con3(1000000) or con3(1)('000')(000)?
but 1_000_000 or 1..000..000 might work, or a whitespace could be made
mandatory?
Another syntax hack:
local function num( a, ... )
local r = 1.0 * a
for i = 1, select( '#', ... ) do
local v = select( i, ... )
assert( type( v ) == "number" and v >= 0 and v < 1000 )
r = r * 1000 + v
end
return r
end
print( num( 1,000,000,000,000 ) ) --> 1000000000000.0
print( num( 2,012,014,144,567 ) ) --> 2012014144567.0
print( num( 1,000,000,000,000,000,000,000 ) ) --> 1e+21
Converting to floats only when an integer overflow would occur, or
restricting fractions to the last argument is left as an exercise for
the reader.
Philipp
[1]: https://github.com/siffiejoe/lua-fx#reference