BooleanSearchParser

The aim of this class is to take a Boolean Search and to convert it into something that can be used in a MySQL Fulltext Search.

The idea came about after recently working a lot with Boolean Search systems, and after reading this StackOverflow question, nothing really exists out there for MySQL.

Big thanks goes to PHP SQL Parser for having such a lovely Tokeniser and related methods, which made this easier.

Goals

• To provide a good-enough conversion
• To not try and correct mistakes with brackets and quotes etc.

Notes

Use

$parser = new \DuncanOgle\BooleanSearchParser\Parser();

echo $parser->parse("ict OR (technology AND bob)");
// ict (+technology +bob)

Regarding order

Order and brackets are important, more often than not OR logic takes priority

sales OR finance AND manager will become sales finance +manager and not sales +finance +manager

Todo

• Handle the * character
• Turn into a package that can be pulled in via composer
• Move tests over to PHP Unit
• Add custom priority settings (currently its OR>AND>NOT)
• Add optional word stemmer like the one used here

Simple Examples

Input	Output
ict	+ict
ict it	+ict +it
ict OR it	ict it
NOT ict	-ict
it NOT ict	+it -ict
web AND (ict OR it)	+web +(ict it)
ict OR (it AND web)	ict (+it +web)
ict NOT (ict AND it AND web)	+ict -(+ict +it +web)
php OR (NOT web NOT embedded ict OR it)	php (-web -embedded ict it)
(web OR embedded) (ict OR it)	+(web embedded) +(ict it)
develop AND (web OR (ict AND php))	+develop +(web (+ict +php))
"ict	null
"ict OR it"	+"ict OR it"

Complex Examples

Input	Output
"business development" or "it sales" and (danish or dutch or italian or denmark or holland or netherlands or italy)	"business development" "it sales" +(danish dutch italian denmark holland netherlands italy)
(procurement or buying or purchasing) and (marine or sea) and (engineering or engineer)	+(procurement buying purchasing) +(marine sea) +(engineering engineer)