Expr.PrintSourceAlias for the type printing functions.
Determine whether to print the map of tags for each id/type/term or not.
Determines whether to print the unique index of each identifier or not.
The name tag is used for the printing of identifiers. When an identifier has an name tag, its value is used instead of the identifier intrinsic name.
Positioning for pretty printing. If this tag is set, the printing functions will ignore type arguments (for readability). Pretty.Infix uses the identifier as a separator when printing th argument list Pretty.Prefix just ignore type arguments.