TC-4 Options

This section documents possible extensions you could implement in TC-4.

type::Error

One problem is that type error recovery can generate false errors. For instance our compiler usually considers that the type for incorrect constructs is Int, which can create cascades of errors.

is_devil.tig

"666" = if 000 then 333 else "666"

tc -T is_devil.tig

$ tc -T is_devil.tig
is_devil.tig:1.9-34: type mismatch
  then clause type: int
  else clause type: string
is_devil.tig:1.1-34: type mismatch
  left operand type: string
  right operand type: int
$ echo $?
5

One means to avoid this issue consists in introducing a new type, type::Error, that the type-checker would never complain about. This can be a nice complement to ast::Error.

Various Desugaring

See TC-D, Removing the syntactic sugar from the Abstract Syntax Tree, for more details. This is quite an easy option, and a very interesting one. Note that implementing desugaring makes TC-L and TC-5 easier.

Renaming object-oriented constructs

Like TC-R, this task consists in writing a visitor renaming AST nodes holding names (either defined or used), this time with support for object-oriented constructs (option --object-rename). This visitor, object::Renamer, shall also update named types (type::Named) and collect the names of all (renamed) classes. This option is essentially a preliminary step of TC-O. See TC-O, Desugaring object constructs.