Re: [odata] Extension of APG for case sensitive strings

[Stefan Drees <stefan@drees.name>]

Hi Ken,

Am 09.11.12 06:00, schrieb kenb:
> In ODATA-117 it was pointed out that string are case insensitive in 
> ABNF. I extended APG so that single-quoted strings are case 
> sensitive.  I also added an option for generating a grammar in 
> standard ABNF so that one can develop a grammar using case sensitive 
> strings and then generate a grammar that is compatible with the ABNF 
> standard.  The code is attached ....

thanks a lot.!

I played with it using the current svn version of our ABNF construction 
rules (stored in check_eapg.txt):

$> java -jar eapg.jar /abnf=out_abnf.txt /eabnf=out_eabnf.txt 
/in=check_eapg.txt /dw

A diff shows the translations from lovely strings like in the production 
for skiptoken:

; svn-source:
skiptoken = %x24.73.6b.69.70.74.6f.6b.65.6e "=" ; $skiptoken
            1*( unreserved / pct-encoded / other-delims / ":" / "@" / 
"$" / "=" ) ; everything except "&"

; out_abnf.txt
skiptoken = %x24.73.6B.69.70.74.6F.6B.65.6E "=" 1*(unreserved / 
pct-encoded / other-delims / ":" / "@" / "$" / "=")


; out_eabnf.txt
skiptoken = '$skiptoken' "=" 1*(unreserved / pct-encoded / other-delims 
/ ":" / "@" / "$" / "=")


The apparent transformations look ok to me.

Are the structural changes it performs when looking at the abnf-output 
also ok?

Sample production for singleNavigation:

; odata-abnf-construction-rules-v1.0-wd01.txt input
singleNavigation = [ "/" qualifiedEntityTypeName ]
                   ( links "/" navigationProperty
                   /  "/" ( entityColNavigationProperty [ 
collectionNavigation ]
                         / entityNavigationProperty    [ singleNavigation ]
                         / complexColProperty          [ collectionPath ]
                         / complexProperty             [ complexPath ]
                         / primitiveColProperty        [ collectionPath ]
                         / primitiveProperty           [ singlePath ]
                         / streamProperty
                         )
                   / boundOperation
                   / ""     ; for casting after key access
                   )

; portion in out_abnf.txt i.e. eapg.jar output (reformatted for 
comparability
singleNavigation = [ "/" qualifiedEntityTypeName ]
                   ((links "/" navigationProperty)
                   / ("/" ((entityColNavigationProperty [ 
collectionNavigation ])
                         /(entityNavigationProperty [singleNavigation])
                         /(complexColProperty [collectionPath])
                         /(complexProperty [complexPath])
                         / (primitiveColProperty [collectionPath])
                         / (primitiveProperty [singlePath])
                         / streamProperty)
                         )
                    / boundOperation
                    / ""
                    )

; abnf output (original formating):
singleNavigation = ["/" qualifiedEntityTypeName] ((links "/" 
navigationProperty) / ("/" ((entityColNavigationProperty 
[collectionNavigation]) / (entityNavigationProperty [singleNavigation]) 
/ (complexColProperty [collectionPath]) / (complexProperty 
[complexPath]) / (primitiveColProperty [collectionPath]) / 
(primitiveProperty [singlePath]) / streamProperty)) / boundOperation / "")


Note eg. the extra parentheses grouping

links "/" navigationProperty

at
singleNavigation = ["/" qualifiedEntityTypeName] ((links "/" 
navigationProperty) / ...

in the output while (space normalizing) the respective input start gives:

singleNavigation = ["/" qualifiedEntityTypeName] ( links "/" 
navigationProperty  / ...

but probably I am to xBNF ignorant to see the equivalence or necessity 
of these parentheses. In that case please ignore or if you are willing 
give me a hint ;-)

If I feed in the eabnf output of the first run:

$> java -jar eapg.jar /abnf=out2fromeabnf_abnf.txt 
/eabnf=out2fromeabnf_eabnf.txt /in=out_eabnf.txt /dw

$> diff -p -U 1 out2fromeabnf_abnf.txt out_abnf.txt

and

$> diff -p -U 1 out2fromeabnf_eabnf.txt out_eabnf.txt

both show the roundtripping works (no differences found).

All the best and thanks again for this both IMO good and interesting 
contribution.

Stefan.