Struct ExprContext 

pub struct ExprContext<'a, T = Schema> { /* private fields */ }

Provides schema-aware context for expression type inference and reference resolution.

An ExprContext binds a schema reference, an optional parent scope (for nested queries), and a target indicating what the expressions reference (a model, table, or source). It is used by the query engine to infer expression types and resolve column/field references.

Examples

use toasty_core::stmt::{ExprContext, ExprTarget};

let cx = ExprContext::new(&schema);
let ty = cx.infer_expr_ty(&expr, &[]);

Implementations

impl<'a, T> ExprContext<'a, T>

pub fn schema(&self) -> &'a T

Returns a reference to the schema.

pub fn target(&self) -> ExprTarget<'a>

Returns the current expression target.

pub fn target_at(&self, nesting: usize) -> &ExprTarget<'a>

Return the target at a specific nesting

impl<'a> ExprContext<'a, ()>

pub fn new_free() -> ExprContext<'a, ()>

Creates a free context with no schema and no target.

impl<'a, T> ExprContext<'a, T>

where T: Resolve,

pub fn new(schema: &'a T) -> ExprContext<'a, T>

Creates a context bound to the given schema with a free target.

pub fn new_with_target( schema: &'a T, target: impl IntoExprTarget<'a, T>, ) -> ExprContext<'a, T>

Creates a context bound to the given schema and target.

pub fn scope<'child>( &'child self, target: impl IntoExprTarget<'child, T>, ) -> ExprContext<'child, T>

Creates a child context with a new target, linked to this context as parent for nested scope resolution.

pub fn resolve_expr_reference( &self, expr_reference: &ExprReference, ) -> ResolvedRef<'a>

Resolves an ExprReference::Column reference to the actual database Column it represents.

Given an ExprReference::Column (which contains table/column indices and nesting info), returns the Column struct containing the column’s name, type, constraints, and other metadata.

Handles:

• Nested query scopes (walking up parent contexts based on nesting level)
• Different statement targets (INSERT, UPDATE, SELECT with joins, etc.)
• Table references in multi-table operations (using the table index)

Used by SQL serialization to get column names, query planning to match index columns, and key extraction to identify column IDs.

pub fn infer_stmt_ty(&self, stmt: &Statement, args: &[Type]) -> Type

Infers the return type of a statement given argument types.

pub fn infer_expr_ty(&self, expr: &Expr, args: &[Type]) -> Type

Infers the type of an expression given argument types.

pub fn infer_expr_reference_ty(&self, expr_reference: &ExprReference) -> Type

Infers the type of an expression reference (field or column).

impl<'a> ExprContext<'a>

pub fn target_as_model(&self) -> Option<&'a ModelRoot>

Returns the context target as a ModelRoot reference, or None if the target is not a model.

pub fn expr_ref_column(&self, column_id: impl Into<ColumnId>) -> ExprReference

Creates an ExprReference::Column for the given column ID.

Panics

Panics if the context has no table target (ExprTarget::Free), if the column does not belong to the table associated with the current target, or if the target’s model has no mapped database table.

Trait Implementations

impl<'a, T> Clone for ExprContext<'a, T>

fn clone(&self) -> ExprContext<'a, T>

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl<'a, T> Debug for ExprContext<'a, T>

where T: Debug,

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

Formats the value using the given formatter.

impl<'a, T> Copy for ExprContext<'a, T>