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Entrypoints `parameter_of`: new keyword for obtaining contract's (from module) parameter

E. Rivas requested to merge er433/attrs/parameter_of into dev

Motivation and Context

In some cases it could be useful to have a way of obtaining the parameter from a module (interpreted as a contract because of @entry attributes).


This MR adds a new keyword parameter_of for obtaining the parameter of a contract.


  • 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)


A new keyword is introduced: parameter_of. It can be used to obtain the type of a contract (from a module/namespace):

namespace C {
  type storage = int;

  // @entry
  const increment = (action: int, store: storage) : [list <operation>, storage] => [list([]), store + action];

  // @entry
  const decrement = (action: int, store: storage) : [list <operation>, storage] => [list([]), store - action];

const test_increment = (() => {
  let initial_storage = 42;
  let [taddr, _, _] = Test.originate_module(contract_of(C), initial_storage, 0 as tez);
  let contr : contract<parameter_of C> = Test.to_contract(taddr);
  let p : parameter_of C = Increment(1);
  let _ = Test.transfer_to_contract_exn(contr, p, 1 as mutez);
  return assert(Test.get_storage(taddr) == initial_storage + 1);
}) ();

As in the case of contract_of, now parameter_of becomes reserved. To still use parameter_of as an identifier, @ can be prepended.


  • 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).
Edited by E. Rivas

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