Implement `String.concats` and `Bytes.concats` in stdlib

E. Rivas requested to merge er433/stdlib/concats into dev

Motivation and Context

As it was reported by Rodrigo in #ligo, there are missing functions for concatenating lists of bytes and strings (using Michelson's CONCAT).


In this MR we implement CONCAT for lists of bytes/strings using an internal op. C_CONCATS.

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)


New functions have been implemented for concatenating lists of strings and bytes:

  • String.concats : string list -> string
  • Bytes.concats : bytes list -> bytes


  • 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

Merge request reports