So, we need a special treatement when dealing with logical operators. Agree?

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Is it considered as a bug?

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The common way when we use the "and" operator as php does is to not evaluate the seconds condition. By allow it, we need to change our code regarding what we should do with PHP.

Example:

if (isset($value) && checkSomething($value)) ? echo 'true' : echo 'false';

In this example, until $value is false checkSomething() will never be interpreted!

For someone this could be considered as a bug or an improvement.

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Who want to address this issue? /cc @hoaproject/hoackers

Design and algorithm

We are speaking about introducing lazy evaluation in operators.
Reminder: functions and operators are strictly the same. An operator is just a function with 2 arguments.

The algorithm is the following:

• we evaluate arguments one after the other,
• if one is evaluated as X then we Y the evaluation,

where X can be anything and Y can be break or continue.

How to solve?

This can be done in 2 steps:

1. inside Hoa\Ruler\Model\Operator, we can add a lazy evaluation flag (on or off) and a lazy evaluation condition (X and Y); flag would be turned off by default, on if the operator is and or or,
2. inside Hoa\Ruler\Visitor\Asserter, in the visitOperator method, the received $element is of kind Hoa\Ruler\Model\Operator, so regarding the lazy evaluation flag and condition, we can visit arguments and apply the above algorithm.

Thoughts?

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This is a good improvement indeed.

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👍 I think this is a good improvement... To me, this is not really a bug just a missing feature.

BTW, reading your comments, it seems you only talk about the and operator but this should also apply to the logical or: http://3v4l.org/FPMFp

-- EDIT --

My bad, I just saw the or mentioned in @Hywan's last comment:

flag would be turned off by default, on if the operator is and or or,

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@jubianchi 👍
@Hywan 👍

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@Hywan 👍 and yes should not be tagged as a bug, it's a design consideration (not even sur if it's a feature, should be benchmarked agains more or less complex expressions and if the lazy version wins all time this is not even an option that you can switch on or off).

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Any volunteers for a PR :-)?

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Let's go, I will try it!

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@vonglasow w00t! Excellent initiative 👍.

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technically speaking, i think this is called boolean short circuit evaluation. Here is a stackoverflow question on this topic http://stackoverflow.com/q/1232603/80353 I think this will be a good feature especially for use cases with 1000s of rules that require assertions.

I think the lazy evaluation or short circuit evaluation should be turned on by default just like most modern languages.

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@simkimsia It will be enabled by default ;-). Thanks for the link!

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👍 Woot Woot!

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I think is done ;)

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@vonglasow Thanks for the clean up ;-).

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