Struct ColRef 

pub struct ColRef {
    pub qualifier: Option<Ident>,
    pub name: Ident,
}

A column reference: an optional qualifier and a name, taken straight off the AST. Stores sqlparser Idents (which keep quote-style) and compares with dialect-aware folding, never raw-string equality.

Fields

qualifier: Option<Ident>

The qualifier (a in a.x), if the reference was compound.

name: Ident

The column name (x in a.x, or in a bare x).

Implementations

impl ColRef

pub fn bare(name: impl Into<String>) -> Self

Build a bare (unqualified) column reference by name.

pub fn from_expr(e: &Expr) -> Option<ColRef>

Read a ColRef from a column-reference expression (Identifier/CompoundIdentifier, seeing through a Nested wrapper). Returns None for any expression that is not a column reference.

pub fn from_wrt_arg(func: &str, e: &Expr) -> Result<ColRef>

Parse the wrt argument of a marker: it must be a bare column (Identifier/CompoundIdentifier), never an expression (F: the design rejects grad(x*y, x+y)).

pub fn classify(&self, wrt: &ColRef, casing: IdentCasing) -> Match

Classify an occurrence self against the differentiation variable wrt under a folding policy — the whole of the ambiguity guard (F2).

The guard fires (returns Match::Ambiguous) only on an uncertain occurrence of the wrt base name; a non-matching name is always Match::Not, and a fully-qualified unambiguous match (e.g. a.x against a.x) is Match::Is with no error.

pub fn display(&self) -> String

Render for error messages (e.g. a.x or x).

Trait Implementations

impl Clone for ColRef

fn clone(&self) -> ColRef

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for ColRef

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

Formats the value using the given formatter.