PHP & ZF2 / Comparison: expected == actual

Question

does anyone know why some developers (especially seen in the sources of Zend Framework 2) write the expected value before the actual value in comparisons?

Example:

if (true === $actualValue) { ... }

instead of

if ($actualValue === true) { ... }

This case is not defined in the PSR coding standard.

Note: There is a similar topic for c++ but without really helpful answers.

I thought it was as a way of eliminating the possibility of assignment within a condition accidentally (i.e. if you forget one of the equals signs). Not sure if that's the main reason, but I've seen that before. true = $actualValue throws a parse error, while $actualValue = true doesn't. — Benno
– Benno, Commented Aug 20, 2012 at 11:40

Kristoffer Sall-Storgaard · Accepted Answer · 2012-08-20 11:45:49Z

10

What you are seeing is Yoda conditions. There is no standard defining these (at least not to my knowledge). They are merely a way to protect yourself against a common coding error (assignment in your conditions).

Example:

if( number = 4 ) // Works perfectly if( 4 = number ) // Throws an exception

edited Aug 20, 2012 at 11:45

answered Aug 20, 2012 at 11:39

Kristoffer Sall-Storgaard

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4 Comments

Fluffeh Over a year ago

+1 for reading the question correctly (unlike I did) and knowing the reference :)

Kristoffer Sall-Storgaard Over a year ago

I had to look it up, but I did know the name, Jeff recently blogged about it: codinghorror.com/blog/2012/07/new-programming-jargon.html

Fluffeh Over a year ago

Good god, I wish I could Give you another +1 for the laughs I just got from the link. I normally just read Joel

Daniel M Over a year ago

Thanks for the answers. May the force be with you.

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