Lotus.Query.OptionalClause (Lotus v1.2.0)

Processes [[...]] optional clause syntax in any text-based query language.

Clauses wrapped in double brackets are stripped entirely when the enclosed variables have no value, making them optional. When all variables inside a block have values, the brackets are removed and the content is kept.

The [[ ... ]] / {{var}} template syntax is language-agnostic — it works on SQL, JSON DSLs, Cypher, or any other textual query format. Adapters that work on AST representations should apply this before serialization.

Blocks are found with Lotus.Query.Tokenizer, so [[ inside a string literal or a comment is plain text, and a {{var}} inside a comment does not make a block conditional. Blocks nest: an inner block is resolved on its own, and the outer block only depends on the variables directly inside it. Every function takes an optional Lotus.Query.Tokenizer.Profile; the default is ANSI SQL.

Example (SQL)

SELECT * FROM users
WHERE 1=1
  [[AND "name" ILIKE '%' || {{name}} || '%']]
  [[AND "status" = {{status}}]]

If name has no value, the first [[...]] block is removed entirely. If status has a value, the second block becomes AND "status" = {{status}}.

Summary

Functions

extract_optional_variable_names(sql, profile \\ Profile.for_language("sql"))

Returns a MapSet of variable names that appear inside [[...]] blocks.

process(sql, supplied_vars, profile \\ Profile.for_language("sql"))

Processes optional clauses in SQL. Removes [[...]] blocks where any enclosed variable has no value. Keeps content (without brackets) when all variables have values.

strip_brackets(content, profile \\ Profile.for_language("sql"))

Strips [[ and ]] brackets from the string, keeping the inner content.