TypeScript Type Aliases

[alexisthedev]

This is still a WIP. Opened PR for status reports and discussion on the progress of this feature since GitHub does not allow to reference already existing branches in Issues (#8).

[alexisthedev]

(WIP)

Things that need to be completed

• Extend AST for TypeScript type alias nodes
• Add type aliases as a type in typescript_types
• Extend generator by extending the list in top_level_decl through calling a builtin factory method with type alias gen func
• Add decl to context (look into already existing add_type function)

[alexisthedev]

What's left in this PR is solving a new bug that has appeared after adding type aliases, where hephaestus can not correctly recognize subtyping relations (ie. trying to assign a boolean to a number).

[alexisthedev]

Type Aliases are ready to go! For more information on the issue described on my previous message, please read this. A similar issue was encountered and fixed while developing the Union Types feature.

After adding complete support for TypeScript's Structural Typing system and Union Types, we will proceed with adding both Union Types as candidates for Type Aliases (should be trivial after adding support for these features). Keep an eye out for the progress on that update in the Union Types pull request.

[theosotr]

Good job!

Please also add unit tests for checking that the subtyping relations of the TypeAlias, StringLiteralType, and NumberLiteralType types work as expected.

[alexisthedev]

This should be ready to merge after pushing the required unit tests.