Sequence¶
AST nodes for sequence-level constructions.
These models represent sequences of tokens, repetition quantifiers,
parenthesized groups, logical union/intersection/negation at the
sequence level, and the _ underscore used in relation queries where applicable
Bases: BCQLNode
An ordered sequence of adjacent tokens / sub-queries. A very high-level node type that can represent an entire query or a sub-sequence
Attributes:
| Name | Type | Description |
|---|---|---|
children |
list[BCQLNodeUnion]
|
The ordered list of child nodes in the sequence. |
Bases: BCQLNode
A repetition quantifier applied to a sub-query.
Supports + (1+), * (0+), ? (0 or 1), {n}, {n,m},
{n,}. Note that "up to" quantifiers like {0,m} are exported as
{,m} and may therefore be different in surface form from the original.
Attributes:
| Name | Type | Description |
|---|---|---|
child |
BCQLNodeUnion
|
The sub-query being repeated. |
min_count |
int
|
Minimum number of repetitions (inclusive, min. 0). |
max_count |
int | None
|
Maximum number of repetitions (inclusive), or |
Bases: BCQLNode
A parenthesized group of sub-queries.
Groups allow applying repetition operators or capture constraints to a complex sub-expression. We specify that there can only be one child node in a group, which typically would be a SequenceNode if there are multiple adjacent tokens or a token-level Node.
Attributes:
| Name | Type | Description |
|---|---|---|
child |
BCQLNodeUnion
|
The inner sub-query. |
Bases: BCQLNode
Sequence-level boolean combination (&, |, ->).
Binary, left-associative node mirroring the booleanOperator rule in Bcql.g4:
all three operators share the same precedence. For example, "a" | "b" & "c"
parses as ("a" | "b") & "c".
Attributes:
| Name | Type | Description |
|---|---|---|
operator |
Literal['&', '|', '->']
|
The boolean operator. |
left |
BCQLNodeUnion
|
The left operand. |
right |
BCQLNodeUnion
|
The right operand. |
Bases: BCQLNode
Sequence-level negation (!).
Negation sits at the span level in the precedence chain (above repetition), so
!"man"+ parses as !("man"+) per Bcql.g4's sequencePartNoCapture rule.
The child is always a single span-level node (never a bare sequence), so
to_bcql just prepends ! without extra parentheses.
Attributes:
| Name | Type | Description |
|---|---|---|
child |
BCQLNodeUnion
|
The sub-query being negated. |