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use crate::{
ast::{
Assignment, ConflictAction, ConflictTarget, InsertSource, InsertStmt, ObjectName,
OnConflict,
},
lexer::TokenKind,
parser::{Parser, ParserError},
};
impl<'a> Parser<'a> {
/// Parses an `INSERT INTO` statement.
///
/// # Grammar
///
/// ```text
/// INSERT INTO table_name [(col1, col2, ...)]
/// ( VALUES (expr, ...) [, (expr, ...)]*
/// | SELECT ...
/// | DEFAULT VALUES )
/// [ON CONFLICT [(col1, ...) | ON CONSTRAINT name]
/// DO NOTHING
/// | DO UPDATE SET col = expr [, col = expr]* [WHERE expr]]
/// [RETURNING select_item [, select_item]*]
/// ```
///
/// # Errors
///
/// Returns [`ParserError`] if any required token is missing or a
/// sub-clause (column list, row tuple, conflict target/action,
/// returning list) is malformed.
pub fn parser_insert(&mut self) -> Result<InsertStmt, ParserError> {
// parse_statement dispatches to this function without consuming
// INSERT itself, so it is consumed here.
self.consume(&TokenKind::Insert);
self.expect(TokenKind::Into)?;
let table = ObjectName(self.parse_qualified_name()?);
let columns = self.parse_insert_columns()?;
let source = self.parse_insert_source()?;
let on_conflict = self.parse_on_conflict()?;
let returning = self.parse_returning()?;
Ok(InsertStmt {
table,
columns,
source,
on_conflict,
returning,
})
}
/// Parses an optional explicit column list: `(col1, col2, ...)`.
///
/// An empty result means no column list was given. Callers (the
/// binder) interpret this as "all table columns, in table-declared
/// order".
fn parse_insert_columns(&mut self) -> Result<Vec<crate::common::symbol::Symbol>, ParserError> {
let mut columns = vec![];
if self.consume(&TokenKind::LParen) {
loop {
columns.push(self.expect_identifier()?);
if !self.consume(&TokenKind::Comma) {
break;
}
}
self.expect(TokenKind::RParen)?;
}
Ok(columns)
}
/// Parses the row-source clause: `VALUES (...)`, `SELECT ...`, or
/// `DEFAULT VALUES`.
fn parse_insert_source(&mut self) -> Result<InsertSource, ParserError> {
match self.current_token() {
TokenKind::Values => {
self.advance();
Ok(InsertSource::Values(self.parse_value_rows()?))
}
TokenKind::Select | TokenKind::With => {
Ok(InsertSource::Select(Box::new(self.parse_select()?)))
}
TokenKind::Default => {
self.advance();
self.expect(TokenKind::Values)?;
Ok(InsertSource::DefaultValues)
}
_ => Err(ParserError::new(
format!(
"Expected VALUES, SELECT, or DEFAULT VALUES after INSERT INTO, found {:?}",
self.current_token()
),
self.current_span().clone(),
)),
}
}
/// Parses one or more parenthesized, comma-separated row tuples:
/// `(expr, expr, ...) [, (expr, expr, ...)]*`.
///
/// Assumes `VALUES` has already been consumed by the caller.
fn parse_value_rows(&mut self) -> Result<Vec<Vec<crate::ast::Expr>>, ParserError> {
let mut rows = Vec::new();
loop {
self.expect(TokenKind::LParen)?;
let mut row = Vec::new();
loop {
row.push(self.parse_expr()?);
if !self.consume(&TokenKind::Comma) {
break;
}
}
self.expect(TokenKind::RParen)?;
rows.push(row);
if !self.consume(&TokenKind::Comma) {
break;
}
}
Ok(rows)
}
/// Parses an optional `ON CONFLICT [target] action` clause.
///
/// Returns `Ok(None)` if the statement has no `ON CONFLICT` clause.
fn parse_on_conflict(&mut self) -> Result<Option<OnConflict>, ParserError> {
if !self.consume(&TokenKind::On) {
return Ok(None);
}
self.expect(TokenKind::Conflict)?;
let target = self.parse_conflict_target()?;
let action = self.parse_conflict_action()?;
Ok(Some(OnConflict { target, action }))
}
/// Parses an optional conflict target: either a column list
/// `(col1, col2, ...)` or `ON CONSTRAINT constraint_name`.
///
/// Returns `Ok(None)` if neither form is present, which is valid SQL —
/// `ON CONFLICT DO NOTHING` may omit the target and rely on any
/// applicable unique or exclusion constraint.
fn parse_conflict_target(&mut self) -> Result<Option<ConflictTarget>, ParserError> {
if self.consume(&TokenKind::LParen) {
let mut cols = vec![self.expect_identifier()?];
while self.consume(&TokenKind::Comma) {
cols.push(self.expect_identifier()?);
}
self.expect(TokenKind::RParen)?;
return Ok(Some(ConflictTarget::Columns(cols)));
}
if self.current_token() == &TokenKind::On {
self.advance();
self.expect(TokenKind::Constraint)?;
let name = self.expect_identifier()?;
return Ok(Some(ConflictTarget::Constraints(name)));
}
Ok(None)
}
/// Parses the conflict action: `DO NOTHING` or
/// `DO UPDATE SET col = expr, ... [WHERE expr]`.
fn parse_conflict_action(&mut self) -> Result<ConflictAction, ParserError> {
self.expect(TokenKind::Do)?;
if self.consume(&TokenKind::Nothing) {
return Ok(ConflictAction::DoNothing);
}
self.expect(TokenKind::Update)?;
self.expect(TokenKind::Set)?;
let mut assignments = Vec::new();
loop {
let column = self.expect_identifier()?;
self.expect(TokenKind::Eq)?;
let value = self.parse_expr()?;
assignments.push(Assignment { column, value });
if !self.consume(&TokenKind::Comma) {
break;
}
}
let where_ = if self.consume(&TokenKind::Where) {
Some(self.parse_expr()?)
} else {
None
};
Ok(ConflictAction::DoUpdate {
assignments,
where_,
})
}
/// Parses an optional `RETURNING select_item [, select_item]*` clause.
///
/// Returns an empty `Vec` if no `RETURNING` clause is present.
fn parse_returning(&mut self) -> Result<Vec<crate::ast::SelectItem>, ParserError> {
if !self.consume(&TokenKind::Returning) {
return Ok(vec![]);
}
let mut items = Vec::new();
loop {
let item = if self.consume(&TokenKind::Star) {
crate::ast::SelectItem::Wildcard
} else {
let expr = self.parse_expr()?;
let alias = if self.consume(&TokenKind::As) {
Some(self.expect_identifier()?)
} else if matches!(self.current_token(), TokenKind::Ident) {
Some(self.expect_identifier()?)
} else {
None
};
crate::ast::SelectItem::Expr { expr, alias }
};
items.push(item);
if !self.consume(&TokenKind::Comma) {
break;
}
}
Ok(items)
}
}