tree of which the current structure is the root. @code{where} is the locus of
this expression in the source code.
-Depending on the flavour of the expression being described by the object
+Depending on the flavor of the expression being described by the object
(that is, the value of its @code{expr_type} member), the corresponding structure
in the @code{value} union will usually contain additional data describing the
expression's value in a type-specific manner. The @code{ref} member is used to