This class provides a parser which can construct an SQL WHERE clause from a Google-like search expression.
The expression recognizes boolean "AND", "OR", and "NOT" (providing no operator between keywords implies "AND"), like so:
cat and dog cat or dog cat and not dog
If no operator appears between keywords or quoted strings, "AND" is assumed. A comma can be used instead of "OR":
cat dog cat, dog cat not dog
The parser recognizes parentheses, so complex expressions can be created:
cat and not (dog or puppy)
Quoted strings are also recognized, and are taken as literal keywords:
"cat and dog"
Parsing is designed to be as fuzzy as possible, so it shouldn't error unless people search for "AND", "OR", or "NOT" without quoting it or use unbalanced parentheses.
parse(string $column, string $expr) : string
Parses a keyword expression.
| string | $column | This is the SQL field name the resulting expression should test against. |
| string | $expr | This is the keyword expression we want to parse. |
The query expression.