Module std.functional.tuple
Tuple container.
An interned, immutable, nil-preserving tuple object.
Like Lua strings, tuples with the same elements can be quickly compared
with a straight-forward == comparison.
The immutability guarantees only work if you don't change the contents of tables after adding them to a tuple. Don't do that!
Objects
| Tuple | Immutable Tuple container. |
Metamethods
| __call ([i=1[, j=self.n]]) | Unpack tuple values between index i and j, inclusive. |
| prototype:__len () | Return the length of this tuple. |
| prototype:__newindex (k, v) | Prevent mutation of tup. |
| prototype:__tostring () | Return a string representation of tup |
Objects
- Tuple
-
Immutable Tuple container.
Fields:
- _type string object name (default 'Tuple')
- n integer number of tuple elements
Usage:
local Tuple = require 'std.functional.tuple' function count(...) argtuple = Tuple(...) return argtuple.n end count() --> 0 count(nil) --> 1 count(false) --> 1 count(false, nil, true, nil) --> 4
Metamethods
- __call ([i=1[, j=self.n]])
-
Unpack tuple values between index i and j, inclusive.
Parameters:
- i integer first index to unpack (default 1)
- j integer last index to unpack (default self.n)
Returns:
-
... values at indices i through j, inclusive
Usage:
tup = Tuple(1, 3, 2, 5) --> 3, 2, 5 tup(2)
- prototype:__len ()
-
Return the length of this tuple.
Returns:
-
int
number of elements in tup
Usage:
-- Only works on Lua 5.2 or newer: #Tuple(nil, 2, nil) --> 3 -- For compatibility with Lua 5.1, use operator.len len(Tuple(nil, 2, nil)
- prototype:__newindex (k, v)
-
Prevent mutation of tup.
Parameters:
- k tuple key
- v tuple value
Raises:
cannot change immutable tuple object - prototype:__tostring ()
-
Return a string representation of tup
Returns:
-
string
representation of tup
Usage:
-- "Tuple('nil', nil, false)" print(Tuple('nil', nil, false))