Re: [Boost-users] Interested in parsing tools

Subject: Re: [Boost-users] Interested in parsing tools
From: Diederick C. Niehorster (dcnieho_at_[hidden])
Date: 2009-09-12 20:32:46

This makes me wonder how Xpressive and Spirit compare, both do
compiled parsing statements right?

Can Spirit somehow be seen as Xpressive + more? Why use Xpressive at all then?

Best,
Dee

On Sun, Sep 13, 2009 at 5:59 AM, OvermindDL1 <overminddl1_at_[hidden]> wrote:
> On Sat, Sep 12, 2009 at 1:40 PM, Ramon F Herrera <ramon_at_[hidden]> wrote:
>> OvermindDL1 wrote:
>>>>
>>>> One of my main current interests is parsing. Trying to decide among the
>>>> choices:
>>>>
>>>> - Regex
>>>> - Spirit
>>>> - Xpressive
>>>
>>> Depends on what you are wanting to parse. Â If you want to do, say, a
>>> search and replace in a file, Xpressive is best, if you want to parse
>>> data structures and you want the absolute best speed and a completely
>>> unambiguous grammar, Spirit2.1 for sure. Â Do not bother with Regex
>>> itself as Xpressive can do everything Regex can, but more and better.
>>>
>>
>> Thanks so much!, OvermindDL1...
>>
>> Allow me to describe my target data. I initially had a bunch of files with
>> lines like this:
>>
>> Variable Name = Variable Value
>>
>> These are some examples:
>>
>> --------------------------------------------------------------------
>> My Favorite Baseball Player = George Herman "Babe" Ruth
>>
>> What did you do on Christmas = I rested, computed the % mortgage and visited
>> my brother + sister.
>>
>> (the above should be in a single line)
>>
>> Favorite Curse = That umpire is a #&*%!
>> --------------------------------------------------------------------
>>
>> I quickly solved the above parsing with Regex like this:
>>
>> string variable = "([A-Za-z0-9][\\w\\h\\(\\)\\-\\.,/&]*)";
>> char equal_sign = '=';
>> string value    = "(.+)";
>> assignment      = variable + equal_sign + value;
>>
>> After retrieving the LHS and the RHS I store them for subsequent use in a
>> map<string, string> data structure.
>>
>> My data, however, just became a bit more challenging. It is now divided into
>> blocks:
>>
>> [Unique ID 1]
>> Variable Name = Variable Value
>> Variable Name = Variable Value
>> Variable Name = Variable Value
>>
>> [Unique ID 2]
>> Variable Name = Variable Value
>> Variable Name = Variable Value
>> Variable Name = Variable Value
>>
>> [Unique ID 3]
>> Variable Name = Variable Value
>> Variable Name = Variable Value
>> Variable Name = Variable Value
>>
>> (etc.)
>>
>> Again, I would like to store the new format in a map, using the Unique ID as
>> key to retrieve the block of lines underneath each ID.
>
> Actually, that kind of stuff is very easy to do in Spirit2.1 (in the
> boost trunk or Boost 1.41), it can auto-fill your structures and
> everything, and it is very fast.
>
>
> On Sat, Sep 12, 2009 at 1:40 PM, Ramon F Herrera <ramon_at_[hidden]> wrote:
>> At this stage, I am wondering whether to continue using true and tried (and
>> learned!) Regex, or get my feet wet into more powerful tools, such as the
>> one recommended by Overmind (Xpressive).
>
> As stated, Xpressive can do all Regex can do, but you can also do
> static regex's (compiled by the C++ grammar, much faster then a string
> regex), but Spirit2.1 would still be a lot faster overall (it has been
> timed against a lot of things, and it blows even Xpressive's static
> parsers away).
>
>
> On Sat, Sep 12, 2009 at 1:40 PM, Ramon F Herrera <ramon_at_[hidden]> wrote:
>> How does Xpressive compare with ANTLR? I am torn between them.
>
> Xpressive and ANTLR are two different things. Â ANTLR is like a
> not-as-powerful-and-slower Spirit2.1, a full grammar parser, where
> Xpressive is just a regex parser.
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