Working with Arrays in Merry
A collection of useful stuff I've discovered about arrays:
Dynamic Manipulation
To set an array:
From client: +setprop zell favourite:colours ({ "green", "black" })
From merry: $actor."favourite:colours" = ({ "green", "black" })
Merry array operations:
| Operation | Description |
|---|---|
| array1 = array2 | set array1 to array2 |
| array1 += array2 | Adds all the elements in array2 to array1 |
| array1 |= array2 | "OR"s the two arrays, which essentially adds every element of array2 to array1, except for elements that already exist. |
| array1 &= array2 | "AND"s the two arrays, which removes all elements from array1 that are not also in array2. |
| array1 -= array2 | Removes all elements in array1 that are also in array2. |
Sample code - setting and modifying an array.:
$actor."favourite:colours" = ({ 1 }); /* it's now ({ 1 }) */
$actor."favourite:colours" += ({ 3, 2 }); /* now ({ 1, 3, 2 }) */
$actor."favourite:colours" |= ({ 4, 2 }); /* now ({ 1, 3, 2, 4 }) */
$actor."favourite:colours" &= ({ 2, 3, 4 }); /* now ({ 3, 2, 4 }) */
$actor."favourite:colours" -= ({ 2 }); /* now ({ 3, 4 }) */
... after that code is run, you can access the array like so:
$actor."favourite:colours"[0] -> 3
$actor."favourite:colours"[0 .. 0] -> ({ 3 })
$actor."favourite:colours"[0 .. 1] -> ({ 3, 4 })
The copy() function is useful when modifying for instance arrays and/or mappings, to avoid harming the original source. VAR = ARRAY does not instantly create a copy of ARRAY, which means there is a slight chance that modifying VAR will also modify ARRAY (the original source).
Example(s):
Merry code: copy( "abc" )
Merry result: "abc"
Merry code: copy( ({ "a", "b", "c" }) )
Merry result: ({ "a", "b", "c" })
Merry code: copy( $actor )
Merry result: <Marrach:players:K:kalle>
-- Main.andreww - 04 Sep 2002
Added more descriptions, and the operations table. -- Main.JamesSanders
- 29 Jun 2003
Added copy() helpfile. -- Main.JamesSanders - 09 Oct 2003