Dynamic entries V3

Motivation and Context

Helpers to define initial dynamic entries and an interface for update.

To define a contract with dynamic entries:

• define a storage type of the form {dynamic_entries ; storage = <ty> } (using type puning)
• if any, define initial dynamic entries using attribute @dyn_entry

closes #1791 (closed)

Description

Following @alistair.obrien design here

New entry in std_lib:

• the dynamic_entrypoints type: just (nat,bytes) big_map
• the (p,s) dynamic_entrypoint type: an abstract type used as a typed key into dynamic_entrypoints which winds up being casted to nat
• two helping function in module Dynamic_entrypoints letting you set and get dynamic entries directly from the @dyn_entry declarations:
  • val set_entrypoint (type p s) : (p, s) dynamic_entrypoint -> (p, s) entrypoint option -> dynamic_entrypoints -> dynamic_entrypoints
  • val get_entrypoint (type p s) : (p, s) dynamic_entrypoint -> dynamic_entrypoints -> (p, s) entrypoint option

Changes in the typechecking:

• C_CAST_DYNAMIC_ENTRYPOINT used to cast any (p, s) dynamic_entrypoint to a nat

• C_OPT_OUT_ENTRY used as a placeholder for entries which should not appear in the initial storage

  [%external ("OPT_OUT_ENTRY", ())]

• storage types holding a dynamic_entrypoints field must only have one other field storage

• [@dyn_entry] let x = e is type checked as:

  e : ('param, 'storage) entrypoint
  x : ('param, 'storage) dynamic_entrypoint 

In a dedicated pass (self_ast_typed) and for each module with a contract sort:

• Generate a binder $initial_dynamic_entrypoints of type dyn_entrypoints holding inital dynamic entrypoints definition
• Morph @dyn_entry declarations right-end sides into natural numbers
• Morph all applications C_CAST_DYNAMIC_ENTRYPOINT x to x

LIGO CLI:

If a contract storage has two fields: dynamic_entrypoints and storage then compile storage command expects an expression of type storage and will automatically fill up the dynamic_entrypoints field

Component

• compiler
• website
• webide
• vscode-plugin
• debugger

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Performance improvement (non-breaking change that improves performance)
• None (change with no changelog)

Changelog

Dynamic entrypoints helpers in LIGO

Checklist:

• If a new syntax has been introduced, put a message on slack ligo-lsp
• Changes follow the existing coding style (use dune @fmt to check).
• Tests for the changes have been added (for bug fixes / feature).
• Documentation has been updated.
• Changelog description has been added (if appropriate).
• Start titles under ## Changelog section with #### (if appropriate).
• There is no image or uploaded file in changelog
• Examples in changed behaviour have been added to the changelog (for breaking change / feature).