Struct ListComprehension 

pub struct ListComprehension<X: Extension = NoExt> {
    pub element: Box<Expr<X>>,
    pub vars: ThinVec<Ident>,
    pub source: ComprehensionSource<X>,
    pub filter: Option<Box<Expr<X>>>,
    pub meta: Meta,
}

A DuckDB list comprehension [element for var in source (if filter)?].

Python-style syntax DuckDB desugars to list_transform/list_filter: it maps element over each var drawn from source, keeping only those matching the optional filter. The canonical node keeps the source spelling so a comprehension round-trips; DuckDB binds it only inside COLUMNS(…) when source is a column star, but that is a bind-time rule past this parse-level shape. Boxed inside ArrayExpr::Comprehension to keep the array node within its size budget.

Fields

element: Box<Expr<X>>

The output expression evaluated for each iteration.

vars: ThinVec<Ident>

Loop variables: one name (for x in …) or two (for x, i in … — value plus 1-based index). DuckDB’s binder rejects three or more (lambda max 2); the parser admits a non-empty list so the multi-var form is representable.

source: ComprehensionSource<X>

Input source for this syntax.

filter: Option<Box<Expr<X>>>

Optional filter for this syntax.

meta: Meta

Source location and node identity.

Trait Implementations

impl<X: Clone + Extension> Clone for ListComprehension<X>

fn clone(&self) -> ListComprehension<X>

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl<X: Debug + Extension> Debug for ListComprehension<X>

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl<'de, X> Deserialize<'de> for ListComprehension<X>

where X: Deserialize<'de> + Extension,

fn deserialize<__D>(__deserializer: __D) -> Result<Self, __D::Error>

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl<X: Eq + Extension> Eq for ListComprehension<X>

impl<X: Hash + Extension> Hash for ListComprehension<X>

fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl<X: PartialEq + Extension> PartialEq for ListComprehension<X>

fn eq(&self, other: &ListComprehension<X>) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.

impl<X> Serialize for ListComprehension<X>

where X: Serialize + Extension,

fn serialize<__S>(&self, __serializer: __S) -> Result<__S::Ok, __S::Error>

where __S: Serializer,

Serialize this value into the given Serde serializer.

impl<X: Extension> Spanned for ListComprehension<X>

fn span(&self) -> Span

Return the span for this value.

impl<X: PartialEq + Extension> StructuralPartialEq for ListComprehension<X>