Module ir 

Intermediate representation for the FHIRPath → SQL compiler.

Two layered IRs:

• SqlExpr is a dialect-independent value-level expression. Every FHIRPath sub-expression compiles to one of these. The Dialect trait lowers an SqlExpr to a SQL string per backend.
• PlanNode is the row-source-level plan: scans, lateral unnests, filters, projections, unions, and recursive descents (repeat:).

Stages 2–5 progressively populate the consumers of these types. Stage 1 just defines the shapes so later work has a stable target.

Structs

Column

Output column projected by a Project node.

JsonPath

Ordered sequence of PathSteps applied to a JSON root.

SubQuery

A subquery embedded inside a SqlExpr. Holds the inner plan together with the scalar projection extracted from each row.

Enums

BinOp

Binary operator for SqlExpr::BinOp.

BoundaryKind

Source value type for SqlExpr::Boundary.

BoundarySide

Selects between lowBoundary() and highBoundary() semantics.

JsonType

JSON value-type predicate, used by PathStep::TypeFilter and polymorphic-field guards.

LitValue

Literal scalar value embedded directly in SQL.

PathStep

One navigation step in a JsonPath.

PlanNode

Row-source plan node.

SqlExpr

A dialect-independent value-level SQL expression.

SqlType

SQL type tag used by SqlExpr::Cast and column projections.

UnaryOp

Unary operator for SqlExpr::UnaryOp.

Type Aliases

DialectRef

Boxed dialect handle used by emission helpers.