# Syntax ? using while|until

**URL:** <https://forum.crystal-lang.org/t/syntax-using-while-until/5398>\
**Category:** Help & Support\
**Created:** [February 17, 2023, 7:05pm UTC](https://forum.crystal-lang.org/t/syntax-using-while-until/5398 "2023-02-17T19:05:24Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![jzakiya](https://yyz2.discourse-cdn.com/flex036/user_avatar/forum.crystal-lang.org/jzakiya/32/278_2.png) [@jzakiya](https://forum.crystal-lang.org/u/jzakiya)\
**Post date:** [February 17, 2023, 7:05pm UTC](https://forum.crystal-lang.org/t/syntax-using-while-until/5398/1 "2023-02-17T19:05:24Z")

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I was looking to find the answer to this, but it just became easier to ask here:

In Crystal|Ruby you can do these:

```auto
xzy if ab

xzy unless ab

```

And you can do this in Ruby but not Crystal, and I was just wondering why?

```auto
xzy while ab

xzy until ab

```

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<div class="post-metadata">

**Author:** ![asterite](https://yyz2.discourse-cdn.com/flex036/user_avatar/forum.crystal-lang.org/asterite/32/60_2.png) [@asterite](https://forum.crystal-lang.org/u/asterite)\
**Post date:** [February 17, 2023, 7:16pm UTC](https://forum.crystal-lang.org/t/syntax-using-while-until/5398/2 "2023-02-17T19:16:40Z")

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> **[FAQ](https://github.com/crystal-lang/crystal/wiki/FAQ#why-trailing-whileuntil-is-not-supported-unlike-ruby)**
>
> The Crystal Programming Language. Contribute to crystal-lang/crystal development by creating an account on GitHub.

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<div class="post-metadata">

**Author:** ![jzakiya](https://yyz2.discourse-cdn.com/flex036/user_avatar/forum.crystal-lang.org/jzakiya/32/278_2.png) [@jzakiya](https://forum.crystal-lang.org/u/jzakiya)\
**Post date:** [February 17, 2023, 7:25pm UTC](https://forum.crystal-lang.org/t/syntax-using-while-until/5398/3 "2023-02-17T19:25:43Z")

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Thanks @asterite. I remember seeing that a _looong_ time ago, but couldn’t find it.