[myhdl-list] syntax sugar?

[Haitao Z. <ha...@gm...>]

One thing I miss in the MyHDL idiom is the simple concurrent statement:
a <= expr 
or
assign a = expr

In myhdl one has to do
def assign_blk():
    while 1:
        yield signals in expr
        a.next = expr

or:
def assign_blk():
    def blk():
        a.next = expr
    return always_comb(blk)

AND one needs to keep track of all the generators:
assign_blk_list.append(assign_blk())

Now of course the regular HDL statement and the myhdl are semantically
equivalent, so you may call the regular concurrent assignment simple
syntax sugar. But it does hide the details from the user and it is a
very good abstraction that can be consistently understood. In a real
design when one does a fair amount of concurrent assignment the tedium
of using the myhdl syntax could quickly add up.

I understand since myhdl is embedded in pure python it has to use all
the defs to control the evaluation and the partial evaluation. One
possibility is to add syntax sugar like the following:
assign("a", "expr")

And then hide the details in the assign function. One can try to
dynamically generate the necessary code in the assign function and
call exec, however this does not work with the inspect function used
by toVerilog and always_comb. I am not up to the task of adding this
capability natively to the myhdl codebase.  Another way to get around
it may be to use code generation tools to transform the short hand.
However with the tools I looked up on the web (Cog, Cheetah etc) the
solution seems to be worse than the problem.

Another nice to have (syntax sugar) is to be able to simply say:
clocked(
<code block>
)

instead of
def clocked_blk():
    while 1:
        yield posedge(clk)
        <code block>

clocked_blk_list.append(clocked_blk())

Comes in handy for all synchronous designs, but does not make as much
difference as the cocurrent assignment. This one is no longer python
semantics unless we put all <code block> in a '''string''', but that
would mess up the code highlighting in my editor :(

Haitao