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Re[2]: Testcases for HTTP location grammar [CR130]

From: <georgi.georgiev.pv@hitachi.com>
Date: Fri, 12 Jan 2007 15:42:45 +0900
Message-ID: <XNM1$2$0$3$$8$3$2$A$5000229U45a72dd7@hitachi.com>
To: <www-ws-desc@w3.org>
Cc: <matsuki.yoshino.pw@hitachi.com>, <Tony.Rogers@ca.com>, <plh@w3.org>, <jakaputin@gmail.com>

>I think I agree.  I don't like either of the result sets John presents.
>FWIW, here's what I would expect:
>

If I am understanding your algorithm correctly, there seem to be a few typos in the examples you gave.
For the sake of clarity, would the following be what you had in mind?

>"{town}"       > {town}           > "Paris"     > valid
>"{{town}}"     > {{,town,}}       > "{Paris}"   > valid

                                     "{town}"

>"{{{town}}}"   > {{,{town},}}     > "{Paris}"   > valid
>"{{{{town}}}}" > {{,{{,town,}},}} > "{{Paris}}" > valid

                                     "{{town}}"

>"{{town}"      > {,{town}         > "{Paris"    > invalid

                  {{, town}        > (invalid anyway)

>"{{{town}"     > {{,{town}        > "{Paris"    > valid
>"{town}}"      > {town},}         > "Paris}"    > invalid
>"{town}}}"     > {town},}}        > "Paris}"    > valid
>
>
>I don't know if it's Tony's algorithm, but I mentally parse it as reading
>left to right, consuming {{ and emitting {, consuming {name} and replacing
>it with the data, and consuming }} and emitting }.  I'm sure Philippe will
>come up with a clean formulation with the maximum number of "valid" results.
>
> 
>
>Jonathan Marsh -  <http://www.wso2.com> http://www.wso2.com -
><http://auburnmarshes.spaces.live.com> http://auburnmarshes.spaces.live.com
>
> 
>
>  _____  
>
>From: www-ws-desc-request@w3.org [mailto:www-ws-desc-request@w3.org] On
>Behalf Of Rogers, Tony
>Sent: Thursday, January 11, 2007 5:50 PM
>To: John Kaputin (gmail); Philippe Le Hegaret; www-ws-desc@w3.org
>Subject: RE: Testcases for HTTP location grammar [CR130]
>
> 
>
>I think the parser need to have a stack for braces - I don't believe even a
>state machine can hold all the information we need - when we match up a pair
>we need to know what our state was before we opened that pair. My sketch of
>the processing would go:
>
> 
>
>if the next character is {
>
>a. if previous character was { and top of stack is { then change top of
>stack to {{
>
>b. otherwise stack {  (remembering where it was seen)
>
> 
>
>if the next character is }
>
>a. if top of stack is {{ look for another } immediately following
>
>    i. if next char is }, unstack the {{  - we have a matching pair  {{}}
>
>    ii. if next char is not }, throw error or treat as literal }
>
>b. if top of stack is {, unstack the {  - we have a matching pair {}
>
>c. if stack is empty, throw error or treat as literal }
>
> 
>
>at the end, the stack should be empty, assuming all { matched }, otherwise
>unstack the extras and treat as literals (which is why we remembered their
>locations)
>
> 
>
>To put it into words, I see } or }} as matching to the nearest unpaired { or
>{{, but always respecting nesting. I also see longer sequences of { taken as
>pairs until there's one or none left.
>
> 
>
>So to my mind {{{{X}}}} parses as {{  {{  X  }}  }}  - even though that's a
>questionable construct.  Or do we want to add another rule saying that {{
>cannot be nested inside {{ ?
>
> 
>
>How does that sound?
>
> 
>
>Tony Rogers
>
>CA, Inc
>
>Senior Architect, Development
>
>tony.rogers@ca.com
>
>co-chair UDDI TC at OASIS
>
>co-chair WS-Desc WG at W3C
>
> 
>
>  _____  
>
>From: www-ws-desc-request@w3.org on behalf of John Kaputin (gmail)
>Sent: Fri 12-Jan-07 8:50
>To: Philippe Le Hegaret; www-ws-desc@w3.org
>Subject: Testcases for HTTP location grammar [CR130]
>
>Phillipe,
>Today's working group call concluded that a grammar should define how the
>http location is parsed and you have the action, so as discussed I'm sending
>you some of my testcases. My post [1] is now captured as CR130.
>
>In deciding on the grammatical rules, things to consider include the
>precedence of double curly braces versus single braces and how to match
>pairs of single braces - e.g. by scanning from left to right, by 'inner most
>pair' (or whatever the terminology is), etc.
>
>When trying several approaches in Woden I found it's not as simple as 'find
>a left curly brace, check for a double brace, then scan for a right curly
>brace'. Also, it appeared from my initial interpretation of the spec that
>double curly braces should take precedence over single braces, but this
>produced some unexpected results. A better approach seems to be 'inner most
>pair' takes precedence, then double curly braces, then other single braces.
>
>Below are some test cases using different approaches. "Valid/invalid" simply
>indicates whether non-paired single braces end up in the parsed string
>(literal single braces are okay).
>
>Inner-most pair, then doubles, then unpaired singles. town=Paris:
>
>"{town}"       > {town}           > "Paris"     > valid
>"{{town}}"     > {,{town},}       > "{Paris}"   > invalid
>"{{{town}}}"   > {{,{town},}}     > "{Paris}"   > valid
>"{{{{town}}}}" > {{,{,{town},}},} > "{{Paris}}" > invalid
>"{{town}"      > {,{town}         > "{Paris"    > invalid
>"{{{town}"     > {{,{town}        > "{Paris"    > valid
>"{town}}"      > {town},}         > "Paris}"    > invalid
>"{town}}}"     > {town},}}        > "Paris}"    > valid
>
>Double braces first, then pairs of singles left-to-right. town=Paris:
>
>"{town}"       > {town}           > "Paris"     > valid
>"{{town}}"     > {{,town,}}       > "{town}"    > valid
>"{{{town}}}"   > {{,{,town,}},}   > "{{town}}"  > invalid
>"{{{{town}}}}" > {{,{{,town,}},}} > "{{Paris}}" > invalid
>"{{town}"      > {{,town,}        > "{town}"    > invalid
>"{{{town}"     > {{,{town}        > "{Paris"    > valid
>"{town}}"      > {,town,}}        > "{town}"    > invalid
>"{town}}}"     > {,town,}},}      > "{town}}"   > invalid
>
>Other test cases:
>
>""                      (is an   empty string location valid?)
>"/temperature/"
>"/temperature/{town}/"
>"/temperature/{town}/{state}/{country}"
>"/temperature/{town}/{{{state}}}/{country}"
>
>It would be good if the spec could include similar examples and/or if the
>test suite covered the grammar.
>
>regards,
>John Kaputin
>
>[1] http://lists.w3.org/Archives/Public/www-ws-desc/2007Jan/0045.html
>
>

-- 
Best regards,
Georgi Georgiev
Received on Friday, 12 January 2007 06:43:23 GMT

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