---
title: when two macros are faster than one
draft: "false"
---
While working on my Database datapack (still WIP), I knew I'd want to find 

# scenario
## dataset
The data is stored in a storage `#_macro.array`. Array is populated with a total of 500 entries, each having `id` and `string` fields.
```json
[
	{
		id: 1,
		string: "entry1"
	},
	...
	{
		id: 500,
		string: "entry500"
	}
]
```
## constraints
The objective is to create an interface that receives a keyword, say `entry500`, and searches `#_macro.array` for an entry where the value of `string` matches the keyword.

The keyword must be able to be entered by a player at runtime, and `#_macro.array` can have an arbitrary number of custom entries created by a player.

In TypeScript, it would look something like this:
```ts
function searchArray(keyword: string) {
	// logic
	return theRelevantEntry
}

searchArray('entry500')
```
In mcfunction, this is not so straightforward. Macros would make this really clean:
```vb
function test_namespace:search_array {keyword: "entry500"}
```
Unfortunately, macros come with a performance hit. A more performant method, albeit less elegant, is to store the keyword in NBT storage prior to calling the function. The storage can be removed after the function is run:
```vb
data modify storage test_namespace:test_namespace temp.keyword set value 'entry500'
function test_namespace:search_array
data remove storage test_namespace:test_namespace temp.keyword

```
Once the entry is found, it is stored in the `temp.result` storage, which can then be consumed by another function.

Now for the logic to do the actual array searching...
# one macro
Macros allow us to reach into our array and pick out an entry that matching value in the `string` property. This is something that I didn't realize (for some reason) and was pointed out by **PuckiSilver** and **amandin** on the Datapack Hub discord server.
```vb
... one_macro.array[string:$(keyword)]
```
This method is super clean and results in a one liner that is wordy but simple:
```vb
'# one_macro/_searcharray.mcfunction

$data modify storage test_namespace:test_namespace temp.result set from storage test_namespace:test_namespace one_macro.array[string:$(keyword)]
```
`_searcharray` can then be called using the `temp.keyword` storage:
```vb
'# one_macro/run.mcfunction

data modify storage test_namespace:test_namespace temp.keyword set value 'entry500'

function test_namespace:one_macro/_searcharray with storage test_namespace:test_namespace temp

data remove storage test_namespace:test_namespace temp.keyword

'# call the function that consumes 'temp.result', then remove it
data remove storage test_namespace:test_namespace temp.result
```
# two macro
Another way to crack the problem is through indexing. This was my original plan when I didn't realize that `...[string:$(keyword)]` was possible.

This method requires the creation of an index of the field that is going to be searched. The index will look something like this:
```json
[
	{entry1: 0},
	{entry2: 1},
	...
	{entry500: 499}
]
```
The *key*, e.g. `entry2:` corresponds with the value of a `string` field in the main array, while the value `1` indicates the main array index where we'll find the full entry. The index can be searched with a direct path, `index.$(keyword)`, and the main array can also be searched with a direct reference to the entry index, `array.#(index)`. Keep in mind that *the index must already exist prior to running the search function*. In a practical application, an index could be updated every time the main array is updated. A scheduled task could also audit the index to ensure that it's up to date.

The index search looks like this:
```vb
'# two_macro/_searchindex.mcfunction

$data modify storage test_namespace:test_namespace temp.index set from storage test_namespace:test_namespace two_macro.index.$(keyword)
```
And the array search looks like this:
```vb
'# two_macro/_searcharray.mcfunction

$data modify storage test_namespace:test_namespace temp.result set from storage test_namespace:test_namespace two_macro.array[$(index)]
```
The index and array search functions are then called using the `temp.keyword` storage:
```vb
'# two_macro/run.mcfunction

data modify storage test_namespace:test_namespace temp.keyword set value 'entry500'

function test_namespace:two_macro/_searchindex with storage test_namespace:test_namespace temp

function test_namespace:two_macro/_searcharray with storage test_namespace:test_namespace temp

data remove storage test_namespace:test_namespace temp.keyword
data remove storage test_namespace:test_namespace temp.index

'# call the function that consumes 'temp.result', then remove it
data remove storage test_namespace:test_namespace temp.result
```