APL Hacking: Project Euler Daily (#1)

This is the first of a series of posts as I go through Project Euler in APL to stretch my knowledge of APL. I hope to post one problem a day to this blog.

Problem #1:

∇R←PEONE;X;⎕IO
 ⎕IO←1
⍝ Find the sum of all the multiples of 3 or 5 below 1000.

X←⍳999

R←+/((0=3∣X)∨0=5∣X)/X

∇