PhiloLogic4’s query syntax has 5 basic operators:

1. the plain token, essentially, any word at all, split on space, e.g. token
2. the quoted token–a string in double quotes, which may contain a space, e.g. "token"
3. the range–two tokens separated by a dash, e.g. 1700-1750
4. boolean OR, represented grep-style as |, e.g. token | word
5. boolean NOT, represented SQL-style as NOT, e.g. token.* NOT tokens

This syntax is the same, but interpreted slightly differently, for the two different types of text query fields: word search and metadata search.

Word Searches

Full-text word search is unique in having the concept of a “term”, which is either a single plain/quoted term, or a group of plain/quoted terms joined by |, optionally followed by NOT and another term-like filter expression. When specifying a query, one can select a query method to constrain the relation between terms, such as within k words or in the same sentence

1. plain terms are evaluated without regard to accent or to case. Regexes are permitted.
2. quoted terms are case and accent sensitive. Regexes are permitted.
3. a quoted term with spaces is a phrase: its words are found next to each other, in order. With a query method such as within k words or in the same sentence, the phrase is one term: its words stay together, and the phrase counts as one word for the distance, so "peuple français" souverain within 3 words finds souverain up to 3 words before peuple or after français.
4. the range is not operational. In the future, stub this out to make hyphenated search terms less of a pain to escape.
5. OR can conjoin plain and quoted tokens, and precedes evaluation of phrase distance.
6. NOT is a filter on a preceding term, but cannot stand alone: a.* NOT abalone is legal, NOT a.* is illegal

Lemma and word attribute Searches

If you text collection contains lemma and/or word attribute information (usually in tags), then PhiloLogic allows you to query words based on lemma and/or word attribute value

1. For simple lemma searching, just preprend the lemma with lemma: such as in lemma:have. Regexes are permitted on the token portion of the search, e.g. lemma:constitut.*.
   • Multi-word lemmas (e.g. the French compound parce que) are stored with whitespace collapsed to underscores. Query them as lemma:parce_que, not lemma:parce que.
2. For word attribute searching, use the word:attribute:attribute syntax such as in love:pos:NOUN. Regexes are permitted on the token portion of the search, e.g. lov.*:pos:NOUN.
3. You can combine lemma searching with word attribute filtering. Just preprend your token with lemma: such as in lemma:love:pos:NOUN. Regexes are permitted on the token portion of the search, e.g. lemma:lov.*:pos:NOUN.
4. You can give a token several word attributes, such as in charles:pos:PROPN:ner:PERS: the occurrences of charles that have them all. Regexes are permitted on the token portion here too, e.g. char.*:pos:PROPN:ner:PERS.

Metadata Searches

Metadata values have a syntax of their own: the database’s word-search settings (query_parser_regex) don’t apply to them.

1. plain words separated by spaces must all be words of the value, in any order, regardless of case and (with ascii_conversion) accents. A word with hyphens or apostrophes, as jean-jacques, needs its parts side by side. Regexes are permitted, and match whole words.
2. quoted text must match the ENTIRE value exactly, including spaces and punctuation. It is not a regex. A quote inside it is written twice: "Les Révoltés de la ""Bounty""".
3. ranges, as 1700-1750, -1750 or 1750-, work in numeric fields only. In text fields, - is part of a word.
4. OR (or |) joins alternatives, preceding the implied Boolean AND.
5. NOT excludes what follows, and may stand alone: contrat NOT social is legal, so is NOT rousseau. Objects with no value are not excluded: NOT rousseau NOT NULL leaves them out too.
6. NULL matches the objects with no value, NOT NULL those with one.
7. In date fields, dates are written 1789, 1789-07 or 1789-07-14, and a year or a month matches all its days. A range joins two dates with <=>, from the first day of one to the last of the other, as 1789<=>1790-06; leave one out for no bound: <=>1790, 1789<=>. Dates separated by spaces are alternatives, as with OR.

Metadata objects also have the unique property of recursion, which creates some unusual consequences for search semantics. Searching for a div that has property NOT x does not guarantee that the result does not contain a child with property x, or a parent with property x. This can often be handled at the database level by normalizing metadata to a single fine-grained layer, but is tricky. Likewise, searches for NULL values in recursive objects will often return “virtual” philologic objects, which don’t exist in the XML but are necessary for balanced tree arithmetic.

Regexp syntax

Basic regexp syntax, adapted from the egrep regular expression syntax.

• The character . matches any single character except newline.
• Bracket expressions can match sets or ranges of characters: [aeiou] or [a-z], but will only match a single character unless followed by one of the quantifiers below.
• * indicates that the regular expression should match zero or more occurrences of the previous character or bracketed group.
• + indicates that the regular expression should match one or more occurrences of the previous character or bracketed group.
• ? indicates that the regular expression should match zero or one occurrence of the previous character or bracketed group. Thus, .* is an approximate “match anything” wildcard operator, rather than the more traditional (but less precise) * in many other search engines.