PredicaTree

This is a (somewhat) lightweight library to parse and execute predicate-based structure algorithms.

A useful application example is dynamic sorting.

Installation

Add this to composer.json:

"require": {
	"adeptoas/predicatree": "^1.0.0"
}

Make sure to merge your require-blocks!

Usage

Currently only supports sorting.

Programs

Programs are sequences of predicates executed in order to give some kind of result. You can create your own by extending from Adepto\PredicaTree\Program\Program. Be sure to call the constructor:

protected function __construct($subject, array $predicates, array $aprioriData = [])

It is marked as protected to encourage use of static factory methods. Some pre-defined programs are explained below.

Every program is run by calling $program->run(). Be aware that this only executes the program. If you actually want to retrieve the computation result, you have to call $program->getResult(), which will run the program automatically (if not already done).

Every program has a subject which is the data the program operates on. A program can have optional apriori data, which is an array specifying any value you want

SortProgram

Sorting programs are generated by SortProgram::build(array $data).

The data array is specified as follows:

[
    'apriori'       =>  array,
    'collection'    =>  [
        'a collection specifier (see section below)'
    ],
    'predicates'    =>  [
        'a sequential list',
        'of if-then predicates',
        'just as specified below'
    ]
]

Collections

In order to sort stuff, you have to give it order. Therefor, this library contains some collection types. Features basic sort operations like add, remove and move.

Collections are specified by their type (currently Dictionary and OrderedSet) and their items like so:

[
    'type'  =>  'OrderedSet',
    'items' =>  [1, 3, 7, 9, 11]
]

Predicates

Predicates represent the if-then rules in this package, and are specified as follows:

[
    'if'    =>  [
        'condition' =>  'CONDITION-NAME',
        'arguments' =>  ['all', 'arguments', 'for', 'the', 'condition']
    ],
    'then'  =>  [
        'action'    =>  'ACTION-NAME',
        'arguments' =>  ['all', 'arguments', 'for', 'the', 'action']
    ]
]

Please note that arguments are passed as sequential arrays and thus are order-sensitive

Pre-defined conditions

• EQUAL: two (obvious) arguments, plus an optional boolean for strict comparison
• BETWEEN: needle followed by two boundaries
• IN: needle and haystack, plus an optional boolean for strict comparison
• STR-BEGINS: needle and haystack
• STR-CONTAINS: needle and haystack
• STR-ENDS: needle and haystack
• NOT: a fully specified predicate (as array). Attention: Sequential array with one argument formatted as array means double array braces!!
• AND: any amount of conditions specified as array
• OR: any amount of conditions specified as array

Currently features methods:

• COLLECTION: first argument is collection method, followed by whatever more arguments necessary
• EVAL: a fully specified predicate (as array)
• PRINT: a string and an optional second boolean for applying JSON encoding
• CHAIN: any amount of actions specified as array

Apriori contents can be accessed by prefixing an argument with ::. Nested array access can be realised by infixing the same :: in between keys.

Subject contents can be accessed during program execution by prefixing an argument with __. The part after this marker specifies the exact key under which the collection will be accessed. Plain __ accesses the entire collection contents as array

Examples

Examples will be added to the Examples/ directory once I come up with meaningful examples that don't involve confidential data from my dayjob.