Re: Clojure rookie vs parsing

[sventrax001]

Thanks so much for the useful and informative advice.
Again due to my rookie-ness I was struggling to adapt my old ANTLR grammar 
to instaparse (and did not come back to read new feedback bad me). While 
from the docs instaparse offers more flexibility than ANTLR, the cost is 
dealing with much lower level

Will give a try to Hiccup. The forest-examples.cljc file seems to be what I 
need.

On Wednesday, August 16, 2017 at 9:51:35 PM UTC+1, Alan Thompson wrote:
>
> While Instaparse is (IMHO) the best parser for use with Clojure, you don't 
> have to start from such a low level (i.e. parsing a char stream text 
> file).  Just re-write your original problem a little and you can skip 
> writing a custom parser.
>
> In Clojure, perhaps the most popular format (certainly the tersest format) is 
> Hiccup .  It is written as a 
> series of nested vectors, where the *tag* is the first item and any 
> *attributes* are in a map that is the 2nd item.  We choose the keyword 
> *:value* to label anything on the right of the equals sign in your 
> original data.  You thus end up with this:
>
>
>
> (def ast-hiccup
>   [:HeaderRule {:value :hr-ftp}
> [:Term {:value 100}
>   [:name {:value "ftp"}]
>   [:From {:value 1}
> [:networkPort {:value "21"}]
> [:Protocol {:value 1}
>   [:Tcp {:value 1}]]]
>   [:Then {:value 1}
> [:ProtocolInspection {:value 1}
>   [:ftpRuleSet {:value "frs-ftp"}]]
> [:ServiceDataFlowId {:value 1}
>   [:payload {:value 99}] )
>
> Using the tupelo.forest library 
> ,
>  
> we can easily parse this tree of data and then issue queries on it:
>
>
> (ns tst.demo.core
>   (:use demo.core tupelo.test)
>   (:require
> [tupelo.core :as t]
> [tupelo.forest :as tf] ))
> (t/refer-tupelo)
>
> (dotest
>   (tf/with-forest(tf/new-forest)
> (let [root-hid   (tf/add-tree-hiccup ast-hiccup)
>   tree-1 (tf/hid->tree root-hid)
>   bush-1 (tf/hid->bush root-hid)
>   >> (spyx-pretty bush-1)   ; print the AST in "bush" 
> format (similar to hiccup)
>
>   networkPort-hid (tf/find-hid root-hid [:** :From 
> :networkPort])   ; find the :networkPort node
>   networkPort-value   (spyx (grab :value (tf/hid->node 
> networkPort-hid)))   ; extract the :value from it
> ]
>   (is= bush-1
> [{:value :hr-ftp, :tag :HeaderRule}
>   [{:value 100, :tag :Term}
> [{:value "ftp", :tag :name}]
> [{:value 1, :tag :From}
>   [{:value "21", :tag :networkPort}]
>   [{:value 1, :tag :Protocol}
> [{:value 1, :tag :Tcp}]]]
> [{:value 1, :tag :Then}
>   [{:value 1, :tag :ProtocolInspection}
> [{:value "frs-ftp", :tag :ftpRuleSet}]]
>   [{:value 1, :tag :ServiceDataFlowId}
> [{:value 99, :tag :payload}] )
>
>   (is= networkPort-value "21" ;  verify we found the value 
> "21"
>
> For more examples please see the forest-examples.cljc file 
> 
>  
> and the API docs .  
> More documentation forthcoming.
>
> Enjoy!
> Alan
>
>
>
> On Tue, Aug 15, 2017 at 7:11 PM, dennis zhuang  > wrote:
>
>> In my experience, instaparse + defun is a good choice. 
>>
>> https://github.com/Engelberg/instaparse
>> https://github.com/killme2008/defun/
>>
>> 2017-08-15 22:02 GMT+08:00 Gary Trakhman > >:
>>
>>> I enjoyed working with clj-antlr recently, it's a wrapper over a java 
>>> library, but gives you a fast feedback loop with an interpreter instead of 
>>> generated java code.  The 'clojurey' part is that the output is a nested 
>>> sequence, from there it's really effective to use tree zippers and 
>>> core.match to transform the parse-tree into the data structure you need. 
>>>
>>> Take a look at:
>>> https://github.com/clojure/core.match
>>> https://github.com/aphyr/clj-antlr
>>> https://www.ibm.com/developerworks/library/j-treevisit/
>>> https://github.com/akhudek/zip-visit
>>>
>>> On Tue, Aug 15, 2017 at 9:56 AM Laurens Van Houtven <_...@lvh.cc> wrote:
>>>
 Hi,


 Instaparse is a great parser generator, especially if you already have 
 a BNF.

 Sent from my iPhone

 On Aug 15, 2017, at 08:44, svent...@gmail.com  wrote:

 Thanks for your input. LFE is quite an unexpected "thing".

 What I'm trying to do, is just a "lunch time project"; something that I 
 can target without corporate constrains just as a learning exercise. 
 Furthermore I 

Re: Clojure rookie vs parsing

[sventrax001]

Thanks for your input. LFE is quite an unexpected "thing".

What I'm trying to do, is just a "lunch time project"; something that I can 
target without corporate constrains just as a learning exercise. 
Furthermore I can test the Clojure version against my old working Java 
version.

As I was saying, while experimenting with Instaparse, I'm having the 
feeling it is not the correct Clojure tool for this type of development



On Tuesday, August 15, 2017 at 2:17:50 PM UTC+1, adrians wrote:
>
> If you need the features of Erlang but would like that in a Lisp (not 
> Common Lisp, though) environment, have you taken a look at LFE (Lisp 
> Flavored Erlang)? I'm not trying to discourage you from looking at Clojure, 
> but if you need/depend on some of the features of Erlang, LFE might be a 
> closer fit.
>
> http://lfe.io
>
> On Tuesday, August 15, 2017 at 8:11:53 AM UTC-4, svent...@gmail.com wrote:
>>
>>
>> Hi
>>
>> Months ago I read a review that praised Clojure's clean approach and use 
>> of JVM that is almost always available in my deployments. 
>>
>> My background: started with 370 assembly ( so I'm not young!!!) and 
>> during the last four years I've been using Erlang for network applications. 
>> For my type of work the functional approach, concurrency and bit handling 
>> of Erlang are life savings. Nonetheless I feel "the call" of Clojure. As an 
>> exercise I would like to re implement something I did years ago in Java, 
>> i.e. a sort of parser. What I have on my hands is a DSL like this
>>
>> HeaderRule=hr-ftp
>>Term=100
>>   name="ftp"
>>   From=1
>>  networkPort="21"
>>  Protocol=1
>> Tcp=1
>>up
>> up
>>  up
>>   Then=1
>>  ProtocolInspection=1
>> ftpRuleSet="frs-ftp"
>> up
>>  ServiceDataFlowId=1
>> payload=99
>> up
>>  up
>>   up
>>up
>> HeaderRule=hr-http
>>   ..
>>
>> For my old Java implementation I used state machines to build an internal 
>> representation, sort of an AST, that would be used to analyze pcap files. 
>> In my Clojure challenge, I would like to have a different approach. 
>> Googling around I've found many options: Parsley, Instaparse, cljcc and 
>> more. Some mentioned on www.clojure-toolbox.com seem to be more 
>> abandonware. 
>> At the moment I'm focusing on Instaparse. However, maybe due to the 
>> previous implementation, I feel that this is not the best approach with 
>> Clojure. Certainly my rookie state is leading me the wrong way.
>>
>> Comments and feedback will be greatly appreciated
>>
>> Fred
>>
>>
>>
>>
>>
>>

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Clojure rookie vs parsing

[sventrax001]

Hi

Months ago I read a review that praised Clojure's clean approach and use of 
JVM that is almost always available in my deployments. 

My background: started with 370 assembly ( so I'm not young!!!) and during 
the last four years I've been using Erlang for network applications. For my 
type of work the functional approach, concurrency and bit handling of 
Erlang are life savings. Nonetheless I feel "the call" of Clojure. As an 
exercise I would like to re implement something I did years ago in Java, 
i.e. a sort of parser. What I have on my hands is a DSL like this

HeaderRule=hr-ftp
   Term=100
  name="ftp"
  From=1
 networkPort="21"
 Protocol=1
Tcp=1
   up
up
 up
  Then=1
 ProtocolInspection=1
ftpRuleSet="frs-ftp"
up
 ServiceDataFlowId=1
payload=99
up
 up
  up
   up
HeaderRule=hr-http
  ..

For my old Java implementation I used state machines to build an internal 
representation, sort of an AST, that would be used to analyze pcap files. 
In my Clojure challenge, I would like to have a different approach. 
Googling around I've found many options: Parsley, Instaparse, cljcc and 
more. Some mentioned on www.clojure-toolbox.com seem to be more 
abandonware. 
At the moment I'm focusing on Instaparse. However, maybe due to the 
previous implementation, I feel that this is not the best approach with 
Clojure. Certainly my rookie state is leading me the wrong way.

Comments and feedback will be greatly appreciated

Fred





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