Topics: suggested edits to Simplicity topic

Author: harding

_topics/en/simplicity.md

@@ -9,30 +9,39 @@ categories:
 
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-  **Simplicity** is a work in progress low level programming language with
+  **Simplicity** is a work-in-progress low-level programming language with
   greater flexibility and expressiveness than Bitcoin Script. It allows
   you to verify the safety, security and costs of a program. It also offers
   native merklized scripting, formal semantics and type checking. To use
-  Simplicity on Bitcoin requires a soft fork and a proposal is unlikely to be
-  formalized until at least 2022. Currently there is Simplicity support for
-  test branches of Bitcoin and Elements.
+  Simplicity on Bitcoin will require a soft fork and such a proposal has
+  not yet been made.  Currently there is Simplicity support for test
+  branches of the ElementsProject.org and Bitcoin Core codebases.
 
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-  Simplicity includes supports for Jets, pre-made building blocks that can be
-  combined to construct Simplicity programs. They have efficient machine-code
-  implementations for raw performance. At its core Simplicity consists of
-  nine primitive operators called combinators where semantics are formally
-  specified. However, implementing Bitcoin functionality at such a low level
-  typically results in large, slow and expensive programs. So instead
-  functionality like hash functions and signature verification are implemented
-  in higher level languages like C which are then proved to be equivalent to
-  the pure Simplicity programs. Assuming Simplicity is soft forked into Bitcoin
-  with sufficient jets at some stage, proposed soft forks like
-  [SIGHASH_ANYPREVOUT][topic sighash_noinput] could be utilized on Bitcoin
-  without needing a separate soft fork. Although Simplicity provides certain
-  proofs of correctness, care still needs to be applied in the design of any
-  contract protocol.
+  At its core, Simplicity consists of nine primitive operators called
+  combinators whose semantics are formally specified. However,
+  implementing Bitcoin functionality at such a low level results in
+  large, slow and expensive programs.  Pre-written Simplicity programs
+  that implement basic functions can be added to Bitcoin consensus so
+  that other Simplicity programs can inline those functions using a
+  short identifier, eliminating their size penalty.  The functionality
+  of the inlined Simplicity code can then be reimplemented in more
+  efficient languages, such as C, which can be proved to be equivalent
+  to the pure Simplicity program---eliminating speed or memory
+  penalties.  These substitutions (called *jets*) allow an entire
+  program to be specified in the Simplicity language, including
+  operations like hash functions and signature verification, and yet
+  be executed using code from other languages to achieve performance
+  similar to today's Bitcoin Script.
+
+  Assuming Simplicity is soft forked into Bitcoin with sufficient jets
+  at some stage, new features such as [SIGHASH_ANYPREVOUT][topic
+  sighash_noinput]---which currently requires a soft fork to
+  implement---could be used on Bitcoin without needing separate
+  consensus rule changes.  Although Simplicity provides certain proofs of
+  correctness, care will still need to be applied in the design of any
+  contract protocol that relies on more than just bitcoin encumbrances.
 
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