Muokkaa

Jaa

Compound Template Data Type Issues

  • Artikkeli

When compound data types are created from other data types and parentheses are used to enclose one of the data types, all data types that enclose a parentheses-bracketed data type must also be enclosed by parentheses.

For example, assume that you define a list of GPD integers by using the following templates.

*Template:  LIST_OF_INTS
{
    *Type:  DATATYPE
    *DataType:   ARRAY
    *ElementType:  INTEGER
    *RequiredDelimiter: ","
    *OptionalDelimiter: "<20 09>"
    *ElementTags: (int)
    *ArraySize: *
}
*Template:  LIST_OF_LIST_OF_INTS
{
    *Type:  DATATYPE
    *DataType:   ARRAY
    *ElementType:  LIST_OF_INTS
    *RequiredDelimiter: ":"
    *OptionalDelimiter: "<20 09>"
    *ElementTags: (IntList)
    *ArraySize: *
}

Then, the following values are valid and equivalent expressions of the LIST_OF_LIST_OF_INTS data type.

*ListList: 1,2,3:10,11,12:20,21,22 
*ListList: (1,2,3:10,11,12:20,21,22)
*ListList: ((1,2,3):(10,11,12):(20,21,22))

However, the following value violates the nesting of parenthesis rule.

*ListList: (1,2,3):(10,11,12):(20,21,22)

The preceding example will generate a syntax error because the parser filter assumes any parenthesis that it encounters belongs to the outermost context, the next parenthesis belongs to the next context, and so on.