feat: rename repr to expr

internal/registry/expr.go

@@ -0,0 +1,24 @@
+package registry
+
+// A Expr is a lambda calculus expression. It can have any type of
+// Expresentation, so long as that class is known to the registry it is handled
+// by.
+type Expr interface {
+	// Repr returns the name of the underlying Expresentation. It is assumed if
+	// two expressions have the same Repr(), they have the same Expresentation.
+	Repr() string
+
+	// The base expression data.
+	Data() any
+}
+
+type baseExpr struct {
+	id   string
+	data any
+}
+
+func (r baseExpr) Repr() string { return r.id }
+
+func (r baseExpr) Data() any { return r.data }
+
+func NewExpr(id string, data any) Expr { return baseExpr{id, data} }