Interface LogicalExpression

All Known Implementing Classes:
FilterQuery, FunctionCall.Logical, FunctionCall.Nodes, LogicalExpression.And, LogicalExpression.Comparison, LogicalExpression.Not, LogicalExpression.Or
public sealed interface LogicalExpression permits LogicalExpression.Or, LogicalExpression.And, LogicalExpression.Not, LogicalExpression.Comparison, FilterQuery, FunctionCall.Logical, FunctionCall.Nodes

An expression with a logical result: LogicalTrue or LogicalFalse (RFC 9535, Section 2.3.5).

Expression Query text True if
LogicalExpression.Or @.a || @.b an operand is true
LogicalExpression.And @.a && @.b all operands are true
LogicalExpression.Not !@.a, !(@.a == 1) the operand is false
LogicalExpression.Comparison @.price < 10 the comparison is true (Section 2.3.5.2.2)
FilterQuery @.isbn, $.config.debug the query selects at least one node (existence test)
FunctionCall.Logical match(@.date, '1974-.*') the function gives LogicalTrue
FunctionCall.Nodes myNodes(@.*) the nodelist of the function is not empty (Section 2.4.2)

The operator precedence is: parentheses and functions, then !, then comparisons, then &&, then ||. Thus the parser makes @.a || @.b && @.c into Or[a, And[b, c]]. A tree does not keep parentheses: the structure of the tree gives the grouping.

An existence test is true also for a node with the value null or false. To test the value, use a comparison, for example @.debug == true.