Capture

bcql_py.models.capture

Dealing with capturing inside variable assignment, references to it, and constraints inside capture expressions. This includes the label:body capture operator, annotation references like A.word, and constraint expressions like A.word = "over".

CaptureNode

Bases: BCQLNode

A capture label applied to a sub-query: label:body, e.g. A:[word="hello"].

Everything matched by body is captured under label in the match info.

Attributes:

Name	Type	Description
label	str	The capture group name (e.g. "A").
body	BCQLNodeUnion	The sub-query whose match is captured

AnnotationRef

Bases: BCQLNode

Reference to a captured token's annotation: label.annotation, or a bare capture label.

Examples: - A.word refers to the word annotation of capture A. - A as a bare label (typically used as a function argument, e.g. start(A)).

Attributes:

Name	Type	Description
label	str	Capture group name.
annotation	str	Annotation name, or empty string for a bare label reference.

ConstraintLiteral

Bases: BCQLNode

A literal string value in a capture constraint.

Example: the "over" in A.word = "over".

Attributes:

Name	Type	Description
value	str	The literal string (without quotes)
quote_char	Literal['"', "'"]	The quote character used in the original query, either " or '.

ConstraintComparison

Bases: BCQLNode

A comparison in a capture constraint: left op right.

Supported operators: =, !=, <, <=, >, >=. Operators here do not get their own class; should not be needed here.

Attributes:

Name	Type	Description
operator	Literal['=', '!=', '<', '<=', '>', '>=']	The comparison operator.
left	CaptureConstraintExpr	Left-hand operand (usually an AnnotationRef).
right	CaptureConstraintExpr	Right-hand operand (annotation ref, literal, or function call).

ConstraintBoolean

Bases: BCQLNode

Boolean combination of capture constraints: left op right.

Operators: & (AND), | (OR), -> (implication). All three share the same precedence per Bcql.g4's booleanOperator rule. The -> implication operator is most commonly seen in capture constraints (e.g. A.word = "cat" -> B.word = "dog") but the grammar allows it at every level.

Attributes:

Name	Type	Description
operator	Literal['&', '|', '->']	"&", "|", or "->".
left	CaptureConstraintExpr	Left operand.
right	CaptureConstraintExpr	Right operand.

ConstraintNot

Bases: BCQLNode

Logical NOT in a capture constraint

Attributes:

Name	Type	Description
operand	CaptureConstraintExpr	The constraint being negated.

ConstraintInteger

Bases: BCQLNode

An integer literal in a capture constraint.

Example: the 5 in focus.pos > 5.

Attributes:

Name	Type	Description
value	int	The integer value.

ConstraintFunctionCall

Bases: BCQLNode

A function call in a capture constraint.

Examples: start(A) or end(B) used in expressions like start(B) < start(A).

Attributes:

Name	Type	Description
name	str	Function name (e.g. "start", "end").
args	list[CaptureConstraintExpr]	Function arguments (annotation refs, literals, etc.).

GlobalConstraintNode

Bases: BCQLNode

A query with a global capture constraint.

The constraint expression follows the :: operator and relates captures defined in body.

Example: A:[] "by" B:[] :: A.word = B.word where A:[] "by" B:[] is the body and A.word = B.word is the constraint expression.

Attributes:

Name	Type	Description
body	BCQLNodeUnion	The main query containing captures.
constraint	CaptureConstraintExpr	The constraint expression relating captures.