Re: [Pyparsing] Parsing multiple items into the same Dict

[George P. <ge...@ga...>]

> George -
>
> Is it really necessary to create the dict directly in the ParseResults?
> This could probably be done in some tricky parse actions, but things might
> be simpler if your ParseResults just reflect the expression structure, and
> then walk the structure to build up your nested dict.  Below is one way.
>
> -- Paul
>
>
> from pyparsing import *
>
> s = \
> """
> a.clk  = "----____----____"
> a.rst  = "--------________"
>
> b.clk  = "____----____----"
> b.x    = "________--------"
> """
>
> TIMING_SPEC = Combine('"' + Word('_-') + '"' )
> ident = Word(alphas, alphanums) 
>
> SIGNAL_DEF = ident.setResultsName("GROUP") + \
>            '.' + ident.setResultsName("SIGNAME") + \
>            '=' + \
>            TIMING_SPEC.setResultsName("TIMING_SPEC")
>
> GRAMMAR = OneOrMore( Group(SIGNAL_DEF) )
>
> results = GRAMMAR.parseString(s)
>
> d = {}
> for toks in results:
>     if toks.GROUP not in d:
>         d[toks.GROUP] = {}
>     d[toks.GROUP][toks.SIGNAME] = toks.TIMING_SPEC
>
> print d
> print d.keys()
> for k in d.keys():
>     print k, d[k].keys()
>
>
> Prints out:
> {'a': {'rst': '"--------________"', 'clk': '"----____----____"'}, 'b': {'x':
> '"________--------"', 'clk': '"____----____----"'}}
> ['a', 'b']
> a ['rst', 'clk']
> b ['x', 'clk']
> d['a']['rst'] -> "--------________"
> d['a']['clk'] -> "----____----____"
> d['b']['x'] -> "________--------"
> d['b']['clk'] -> "____----____----"
>
>   
Paul,
    Thanks for your fantastic help! Your detailed example taught me a 
lot. No, I didn't need to create the dict in the parse results directly. 
I'm glad you questioned that because I was starting to go insane ;-)

Here's an excerpt of the solution you helped guide me to. (Note: I 
accidentally used quotes in my timing spec string in the previous email).

If you're curious what I'm doing this for, I'm making a tool for MyHDL 
to increase the fun factor in the design and testing of complex 
electronic systems: 
http://myhdl.jandecaluwe.com/doku.php/users:george_pantazopoulos

Kudos,
George
http://www.gammaburst.net

# ---------------------
from pyparsing import *

def parse_ats_block(ats_block):

    """
    Example input:

    a.clk  = ----____----____
    a.rst  = --------________

    b.clk  = ____----____----
    b.x    = ________--------

    For the Timing Diagram portion:
   
    Input        Parser output            
    ---------------------------------------
    "--__"   =>  ['-', '-', '_', '_']

    "1..72." =>  ['1..', '72.']      
   
    """

    # pyparsing grammar
    # Special thanks to Paul McGuire

    # The OneOrMore() will split up the timing spec into a list of tokens
    TIMING_SPEC = OneOrMore(Regex('[-_]') | Regex('[0-9]+\.+'))
   
    identifier  = Word(alphas, alphanums)
       
    SIGNAL_DEF  = identifier.setResultsName("GROUP") + \
                  '.' + identifier.setResultsName("SIGNAME") + \
                  '=' + TIMING_SPEC.setResultsName("TIMING_SPEC")

    ATS_GRAMMAR = OneOrMore(Group(SIGNAL_DEF))


    # The parse results can be treated as a list of lists of the following
    # form: (Each sublist represents a signal definition)
    # [groupname, '.', signame, '=', timingspec]

    # In addition, thanks to the use of setResultsName()
    # the components can also be accessed using attribute syntax
   
    # Each signal definition entry in the results will contain
    # a .GROUP, .SIGNAME, and .TIMING_SPEC attribute.
   
    # Parse
    results = ATS_GRAMMAR.parseString(ats_block)
   
    # From the parse results create a nested dict.
    # The top level dict contains a dict for each group, keyed by the
    # group name.
    #
    # Each group dict contains key/value pairs where key = signal name
    # and value = the signal's timing spec
   
    d = dict()
    for toks in results:
        if toks.GROUP not in d:
            d[toks.GROUP] = dict()
        d[toks.GROUP][toks.SIGNAME] = toks.TIMING_SPEC
       
    results_dict = d

    return results_dict