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This is a simple package for evaluating boolean logic in a data structure.

The entry point is Criteria::evaluate(array $criteria, callable $accessor).

$criteria is an array of terms. If any of the terms evaluates as true, evaluate returns. This is an implicit "or" operation.

Terms

A term is an array with these elements:

arg - the name of a value to be retrieved via the accessor callback.
op - A comparison operator, see below.
value or var - Required for binary operators (i.e. those other than null, !null), the value to be compared or the regular expression to be matched. The value can be an array. If an array value is provided for a binary operator (other than "in" or "includes"), each value is compared and the first true result causes the expression to be true. If var is provided, it must be a string. This is passed to the accessor callback to retrieve a value from the application.
name - An optional name, used when reporting errors.
invert - An optional boolean. When true, the result of the current (sub-)criteria is inverted.
and - An optional list of sub-criteria. The list is evaluated as a series of logical "or" conjunctions, then a logical "and" is performed against the result of the argument/value operation.
xor - Similar to the and element instead the result is exclusive or-ed with the result.

Element names are configurable to suit the application. See "property configuration" below.

Operators

The operator is one of ==, ===, !=, !==, >, >=, <, <=, contains, !contains, in, !in, includes, !includes, null, !null, regex, !regex. If no operator is specified, then == is assumed.

The "contains" operator is true if var/value is a substring of arg. This test is case-sensitive.
The "in" operator is true if arg can be found in var/value, which normally is an array. If both arg and var/value are scalar, "in" is equivalent to ==. If arg is an array, then the expression is true if all elements in arg can be found in var/value.
The "includes" operator is true if var/value can be found in arg, which normally is an array. If both arg and var/value are scalar, "in" is equivalent to ==. If both arg and var/value are arrays, then the expression is true if all elements in var/value can be found in arg.
The "null" operator is unary, any var/value is ignored.
The "regex" operator expects a PHP regular expression.
A ! in front of "contains", "in", "includes", and "regex" will invert the result of the test.

Examples

Criteria are specified in JSON for readability.

[
  {
    "arg": "language",
    "op": "==",
    "value": "en"
  }
]

Will evaluate true if the value of acessor('language') is "en".

[
  {
    "arg": "firstName",
    "var": "lastName"
  }
]

This assumes the operator is == and Will evaluate true if acessor('firstName') is equal to acessor('lastName').

[
  {
    "arg": "firstName",
    "op": "==",
    "var": "lastName"
  },
  {
    "arg": "firstName",
    "op": "==",
    "var": ""
  }
]

Will evaluate true if acessor('firstName') is equal to acessor('lastName') or if acessor('firstName') is an empty string.

[
  {
    "arg": "province",
    "op": "==",
    "value": "ON",
    "and": [
      {
        "arg": "areaCode",
        "op": "in",
        "value": [
          "226",
          "249",
          "289",
          "343",
          "365",
          "416",
          "437",
          "519",
          "548",
          "613",
          "647",
          "705",
          "807",
          "905"
        ]
      }
    ]
  }
]

Will evaluate true if acessor('province') is "ON" and accessor('areaCode') matches one of the values in the list.

Operator Access Control

If your application is processing user-generated data and you want to restrict access to some operators, this is possible with the operatorState option.

$criteria = new \Abivia\Criteria\Criteria(
   ['operatorState' => ['regex' => false, '!regex' => false]]
);

This will disable use of the regular expression operators.

Property Configuration

Property names used in the criteria can be changed at instantiation by passing an array of replacements. Only the passed in properties will be modified.

$criteria = new \Abivia\Criteria\Criteria(
   ['overrides' => ['arg' => 'left', 'op' => 'operator', 'value' => 'right']]
);

Would change a valid input to:

[
  {
    "left": "firstName",
    "operator": "==",
    "right": "lastName",
    "invert": true
  }
]

abivia / criteria

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