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Date: Sun, 6 Nov 2016 21:29:13 +0100
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Subject: [RFC] Interval Comparison
From: php@fleshgrinder.com (Fleshgrinder)

Validating whether a number is within a closed or open interval is
currently possible only via a construct like the following:

```
if (0 < $x && $x < 42) {
    echo 'x is in (0, 42)';
}

if (0 <= $x && $x <= 42) {
    echo 'x is in [0, 42]';
}
```

It is not very readable and repetitive. It would be interesting to
support a more mathematical notation for this:

```
if (0 < $x < 42) {
    echo 'x is in (0, 42)';
}

if (0 <= $x <= 42) {
    echo 'x is in [0, 42]';
}
```

I cannot judge how complicated it is to extend the Bison definitions to
allow this. However, if there is interest I'm sure there is a way. :)

-- 
Richard "Fleshgrinder" Fussenegger