Syntax tree nodes for language types, of type
Ast.ctyp. The basic nodes are:
<:ctyp< $t1$ . $t2$ >>: access in module.
<:ctyp< $t1$ as $t2$ >>: type alias
<:ctyp< _ >>: wildcard.
<:ctyp< $t1$ $t2$ >>: application.
<:ctyp< $t1$ -> $t2$ >>: arrow.
<:ctyp< $lid:s$ >>: identfier starting with a
lowercase letter.
<:ctyp< '$s$ >>: type variable.
<:ctyp< $t1$ == $t2$ >>: type manifest.
<:ctyp< { $list:sbtl$ } >>: record definition.
<:ctyp< [ $list:stll$ ] >>: concrete type definition.
<:ctyp< ( $list:tl$ ) >>: tuple.
<:ctyp< $uid:s$ >>: identifier starting with an
uppercase letter.