docs: proofread pyosys.rst

Primarily address feedback from @KrystalDelusion (thanks!)

docs/source/using_yosys/pyosys.rst

@@ -4,17 +4,21 @@ Scripting with Pyosys
 Pyosys is a limited subset of the Yosys C++ API (aka "libyosys") made available
 using the Python programming language.
 
-It offers access both to writing Yosys scripts like ``.ys`` and ``.tcl`` files
+Like ``.ys`` and ``.tcl`` scripts, Pyosys provides an interface to write Yosys
-with the amenities of the Python programming language (functions, flow control,
+scripts in the Python programming language, giving you the benefits of
-etc), but also allows some access to internal data structures at the same time
+a type system, control flow, object-oriented programming, and more; especially
-unlike those two platforms, allowing you to also implement complex functionality
+that the other options lack a type system and control flow/OOP in Tcl is
-that is would otherwise not possible without writing custom passes using C++.
+limited.
+
+Though unlike these two, Pyosys goes a bit further, allowing you to use the
+Yosys API to implement advanced functionality that would otherwise require
+custom passes written in C++.
 
 
 Getting Pyosys
 --------------
 
-Pyosys supports Python 3.8.1 or higher. You can access Pyosys using one of two
+Pyosys supports CPython 3.8 or higher. You can access Pyosys using one of two
 methods:
 
 1. Compiling Yosys with the Makefile flag ``ENABLE_PYOSYS=1``
@@ -26,8 +30,8 @@ methods:
 
 2. Installing the Pyosys wheels
 
-   On macOS and GNU/Linux (specifically, not musllinux,) you can install
+   On macOS and GNU/Linux you can install pre-built wheels of Yosys using
-   pre-built wheels of Yosys using ``pip`` as follows:
+   ``pip``:
 
    ``python3 -m pip install pyosys``
 
@@ -56,7 +60,7 @@ this import may be preferable for terseness:
 
 Now, scripting is actually quite similar to ``.ys`` and ``.tcl`` script in that
 you can provide mostly text commands. Albeit, you can construct your scripts
-to use Python's amenities including flow controls, loops, and functions:
+to use Python's amenities like conditional execution, loops, and functions:
 
 .. code-block:: python
 
@@ -67,9 +71,9 @@ to use Python's amenities including flow controls, loops, and functions:
    if do_flatten:
       ys.run_pass("flatten")
 
-…but this does not provide anything that Tcl scripts do not provide you with.
+…but this does not strictly provide anything that Tcl scripts do not provide you
-The real power of using Pyosys comes from the fact you can manually instantiate,
+with. The real power of using Pyosys comes from the fact you can manually
-manage, and interact with the design database.
+instantiate, manage, and interact with the design database.
 
 As an example, here is the same script with a manually instantiated design.
 
@@ -79,8 +83,8 @@ As an example, here is the same script with a manually instantiated design.
    :language: python
 
 What's new here is that you can manually inspect the design's database. This
-gives you access to huge chunk of the design database API as in declared in the
+gives you access to a huge chunk of the design database API as declared in
-``kernel/rtlil.h`` header.
+the ``kernel/rtlil.h`` header.
 
 For example, here's how to list the input and output ports of the top module
 of your design:
@@ -95,12 +99,18 @@ of your design:
    C++ data structures in Yosys are bridged to Python such that they have a
    pretty similar API to Python objects, for example:
 
-   - ``std::vector`` supports the same methods as iterables in Python.
+   - ``std::vector`` supports the same methods as
-   - ``std::set`` and hashlib ``pool`` support the same methods as ``set``\s in
+     `iterables <https://docs.python.org/3/glossary.html#term-iterable>`_ in
      Python.
+   - ``std::set`` and hashlib ``pool`` support the same methods as ``set``\s in
+     Python. While ``set`` is ordered, ``pool`` is not and modifications may
+     cause a complete reordering of the set.
    - ``dict`` supports the same methods as ``dict``\s in Python, albeit it is
      unordered, and modifications may cause a complete reordering of the
      dictionary.
+   - ``idict`` uses a custom set of methods because it doesn't map very cleanly
+     to an existing Python data structure. See ``pyosys/hashlib.h`` for more
+     info.
 
    For most operations, the Python equivalents are also supported as arguments
    where they will automatically be cast to the right type, so you do not have
@@ -121,8 +131,8 @@ to modify it, and introduce new elements and/or changes to your design.
 As a demonstrative example, let's assume we want to add an enable line to all
 flip-flops in our fiedler-cooley design.
 
-First of all, we will run :yoscrypt:`synth` to convert all of the logic to Yosys's
+First of all, we will run :yoscrypt:`synth` to convert all of the logic to
-internal cell structure (see :ref:`sec:celllib_gates`):
+Yosys's internal cell structure (see :ref:`sec:celllib_gates`):
 
 .. literalinclude:: /code_examples/pyosys/simple_database.py
    :start-after: # synth
@@ -163,7 +173,8 @@ Next, we can iterate over all constituent cells, and if they are of the type
    :language: python
 
 To verify that you did everything correctly, it is prudent to call ``.check()``
-on the module you're manipulating as follows:
+on the module you're manipulating as follows after you're done with a set of
+changes:
 
 .. literalinclude:: /code_examples/pyosys/simple_database.py
    :start-after: run check
@@ -177,15 +188,15 @@ file and :yoscrypt:`synth_ice40` to map it to the iCE40 architecture.
    :start-after: write output
    :language: python
 
-And voila, you will note that in the intermediate output, all ``always @``
+And voilà, you will note that in the intermediate output, all ``always @``
-statements have an ``if (enable)``\.
+statements should have an ``if (enable)``\.
 
 Encapsulating as Passes
 -----------------------
 
-Just like when writing C++, you can encapsulate behavior in terms of "passes",
+Just like when writing C++, you can encapsulate routines in terms of "passes",
-which are the commands you access using ``run_pass``\. This adds it to a global
+which adds your Pass to a global registry of commands accessible using
-registry of commands that you can use using ``run_pass``.
+``run_pass``\.
 
 .. literalinclude:: /code_examples/pyosys/pass.py
    :language: python