[GitHub] jena pull request #114: JENA-632: Generate JSON from SPARQL directly

[kinow]

Github user kinow commented on a diff in the pull request:

    https://github.com/apache/jena/pull/114#discussion_r182394976
  
    --- Diff: jena-arq/Grammar/master.jj ---
    @@ -2176,6 +2251,19 @@ String String() : { Token t ; String lex ; }
         }
     }
     
    +#ifdef ARQ
    +Number Number() : { Token t ; Number number ; }
    +{
    +  (
    +    t = < INTEGER > { number = integerValue(t.image) ; }
    +  | t = < DECIMAL > { number = doubleValue(t.image) ; }
    --- End diff --
    
    Oh! It was by accident that it got fixed I think?
    
    I copied parts of the `SelectClause()` to `JsonClause()`. More 
especifically, the Select had:
    
    ```
          // Expressions without ()
          ( LOOKAHEAD(2)
            expr = BuiltInCall()        { getQuery().addResultVar((Var)null, 
expr) ; }
          | expr = FunctionCall()       { getQuery().addResultVar((Var)null, 
expr) ; }
          | n = RDFLiteral()            { getQuery().addResultVar((Var)null, 
NodeValue.makeNode(n)) ; }
          | n = NumericLiteral()        { getQuery().addResultVar((Var)null, 
NodeValue.makeNode(n)) ; }
          | n = BooleanLiteral()        { getQuery().addResultVar((Var)null, 
NodeValue.makeNode(n)) ; }
    ```
    
    Which became the following for the JSON counterpart:
    
    ```
        o = Var() { getQuery().addResultVar((Var)o) ; 
getQuery().addJsonMapping(s, o) ; }
      | o = RDFLiteral() { getQuery().addResultVar(s, NodeValue.makeNode(o)) ; 
getQuery().addJsonMapping(s, o) ; }
      | o = NumericLiteral() { getQuery().addResultVar(s, 
NodeValue.makeNode(o)) ; getQuery().addJsonMapping(s, o) ; }
      | o = BooleanLiteral() { getQuery().addResultVar(s, 
NodeValue.makeNode(o)) ; getQuery().addJsonMapping(s, o) ; }
    ```
    
    More or less the same. But we have the Var (i.e. for cases like `"title" : 
?title`), and then I did not include the expressions (hence the lookahead 
removed).
    
    Does it make sense @afs ? If so, we can actually remove the `Number()` and 
this whole #if ARQ block. And I believe the code is doing more or less what you 
suggested?
    
    Thanks!
    Bruno


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