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Like functions, it's also possible to make user-defined operators. Here's a simple example.

The World Programming Language has different datatypes known as series to hold collections of data. One is the block! datatype:

    block: [1 2 "blue" 3]

The value, "blue", can be removed from the block with this code:

    remove find block "blue"

The same can be achieved using the FROM operator:

    remove "blue" from block

Some may prefer to write it this way to make the code more readable. FROM is defined as:

    from: operator [
        "Finds a value in a series."
        series [series!]
        find series value

To insert "blue" back into the block after 2, instead of writing:

    insert next find block 2 "blue"

you could write:

    insert block after 2 "blue"

where AFTER is defined as:

    after: operator [series value] [next find series value]

The same could in this example be achieved with:

    insert find block 3 "blue"
    insert block before 3 "blue"