Re: [Pyparsing] Grouping when using asList()

[Joshua J. K. <jk...@sk...>]

On Wed, 2008-03-05 at 21:48 -0600, Paul McGuire wrote:
> Ok, here are the changes I made to your code:

Wow...just...wow.  Really, I wasn't asking anyone to write my parser for
me. I just wanted to know how to do it.  Wow.  Thanks you!!

> I changed column_def to:
> 
> col_width_def = (p.Suppress('(') + 
>               p.delimitedList(p.Word(p.nums)).setParseAction( lambda toks:
> [int(tok) for tok in toks]) + 
>               p.Suppress(')')
>               )

That casting to int didn't matter much since we'll be just doing string
output, but it does validate the input. :)

> paren_quoted was just not the expression, and the "(p.nums + p.Optional(','
> + p.nums)" argument *actually* created a results name for the column_width
> field.

Gotcha.

> I changed create_table to:
> 
> create_table = (p.CaselessKeyword('create').suppress()
>                 + p.CaselessKeyword('table').suppress()
>                 + bracket_quoted.setResultsName('schema')
>                 + "." + bracket_quoted.setResultsName('table_name')
>                 #~ + p.nestedExpr(content=p.delimitedList(p.Or(
>                     #~ [p.Group(column_def.setResultsName('columns')),
>                     #~ p.Group(primary_key),
>                     #~ p.Group(constraint)])))
>                 + p.Group(p.Suppress('(') + 
>                         p.delimitedList(p.Or(
>                     [p.Group(column_def).setResultsName('columns',
> listAllMatches=True),
>                     p.Group(primary_key).setResultsName('pkeys',
> listAllMatches=True),
>                     p.Group(constraint).setResultsName('constraints',
> listAllMatches=True)]
>                     ))
>                     + p.Suppress(')')
>                     )("defs")
>                 + p.CaselessKeyword('on').suppress()
>                 + bracket_quoted.suppress()
>                 )
> 
> There was no need to use nestedExpr for the list of column/key/constraint
> items.  Note the use of listAllMatches in the setResultsName calls.

Saw that.  That makes sense.  So, it doesn't change the asList() output
any, but I have attributes I can access by name now. Cool.

One question: ("defs") is a call to what Groups() returns, but I'm not
following. Can you point me to something in the docs that explains what
is done when you call a pyparsing expression?

Again, thanks so much!  I'm much further along to where I need to be.

j

-- 
Joshua Kugler
VOC/SigNet Provider (aka Web App Programmer)
S&K Aerospace Alaska