Module ast 

rudb’s abstract syntax tree.

The parse tree the matcher produces is DuckDB’s grammar, faithfully. That is the point of it and it is also why nothing downstream should read it: a bump of the vendored grammar is allowed to rename BetweenInLikeExpression, and if the binder is matching on that name then the bump is a rewrite. This module is the boundary. It is ours, it changes when we decide it changes, and transform is the one place that knows both shapes.

Everything is an arena with u32 indices, per spec/04-architecture.md section 4.5. There is no Box and no Vec inside a node. A list of children is a Slice into a side vector, which means a node is a fixed size, the whole tree is a handful of allocations, and walking it is a sequential read rather than a pointer chase per node. It also means an Ast is Clone and Send without any thought, and that a subtree can be addressed by a u32 in a plan or an error without borrowing anything.

The one cost is that you cannot hold a reference to a node and index the arena at the same time, so the code reads a node out by value first. Nodes are small and Copy, so that is a register move.

Structs

Alter

ALTER TABLE name action or ALTER VIEW name RENAME TO other.

Ast

A parsed statement or script, with every arena it points into.

Attach

ATTACH [OR REPLACE] [IF NOT EXISTS] [DATABASE] path [AS alias] [(options)].

CaseArm

One WHEN a THEN b.

ColumnDef

One column of a CREATE TABLE.

Conflict

ON CONFLICT, INSERT OR REPLACE or INSERT OR IGNORE.

CopyTo

COPY ... TO, which writes what a query answers to a file.

CreateTable

CREATE TABLE name (columns) or CREATE TABLE name AS query.

CreateView

CREATE VIEW name (columns) AS query.

Cte

A WITH name AS MATERIALIZED (query), which is run once and read wherever it is named.

DropTable

DROP TABLE a, b or DROP VIEW a, b.

Index

CREATE [UNIQUE] INDEX name ON table (elements) or DROP INDEX name.

Insert

INSERT INTO name (columns) query.

OrderItem

One entry of an order by list.

Query

A query: a body, plus the modifiers that apply to whatever the body produced.

Schema

CREATE SCHEMA name or DROP SCHEMA name.

Select

One select block.

Sequence

CREATE SEQUENCE name options or DROP SEQUENCE name.

Setting

SET name = value and RESET name.

Slice

A run of items in one of the side vectors.

Target

One entry of a target list.

TypeDef

CREATE TYPE name AS type or DROP TYPE name.

WindowSpec

Everything inside the parentheses of an OVER.

Enums

AlterAction

What one ALTER TABLE does. A column is named as written.

BinaryOp

An infix operator.

ConflictAction

What happens to a row whose key is already held.

Constraint

One constraint of a CREATE TABLE, by its place in the list of its kind.

Distinct

What the DISTINCT clause of a select said.

Expr

One expression.

JoinKind

Which join.

LiteralKind

Which literal.

Nulls

Null placement in a sort.

Order

Sort direction, with the unwritten case kept apart from the default it resolves to.

Quantifier

Whether a set operator or an aggregate keeps duplicates.

QueryBody

What produces the rows of a query.

Scope

Which copy of a setting a statement means.

SetOp

Which set operator.

Source

One entry in a FROM clause, which is a tree because joins nest.

Statement

One statement.

Transaction

What a transaction statement asks for.

UnaryOp

A prefix or postfix operator.

WindowBound

One end of a window frame.

WindowExclude

Which peers of the current row the frame drops once its bounds have been applied.

WindowUnit

How a window frame measures the distance to its bounds.

Type Aliases

AlterRef

Index into Ast::alters.

AttachRef

An index into Ast::attaches.

CopyToRef

An index into Ast::copies.

CreateTableRef

An index into Ast::create_tables.

CreateViewRef

An index into Ast::create_views.

DropTableRef

An index into Ast::drop_tables.

ExprRef

An index into Ast::exprs.

IndexRef

Index into Ast::indexes.

InsertRef

An index into Ast::inserts.

QueryRef

An index into Ast::queries.

SchemaRef

Index into Ast::schemas.

SelectRef

An index into Ast::selects.

SequenceRef

Index into Ast::sequences.

SettingRef

An index into Ast::settings.

SourceRef

An index into Ast::sources.

StrRef

An index into Ast::strings.

TypeRef

Index into Ast::types.

WindowRef

An index into Ast::windows.