Re: dereferencing multiple hash array structure

Here is an extract from the data structure in DoxyDocs1.pm, re-formatted for greater readability and with one => re-written as quote + comma (see Comma Operator in perlop):

detailed =>
{
    doc =>
    [
        {
            type => 'text',
            content => 'Add a child to the container '
        },
        "params",
        [
            {
                parameters =>
                [
                    {
                        name => 'child'
                    }
                ],
                doc =>
                [
                    {
                        type => 'text',
                        content => 'is the child element to add'
                    }
                ]
            }
        ]
    ]
},
[download]

As you can see, doc is a hash key with a reference to an anonymous array as its value. This array contains 3 elements: a reference to an anonymous hash; the string "params"; and a reference to an anonymous array. As GrandFather says, this is syntactically OK, but it is almost certainly not what was intended — which is why you’re unable to extract the data you want. You will need to re-consider the way this data structure is generated.

Update: Using prototypes on subroutines is usually a bad idea, unless you have a strong reason to. Better to remove the trailing parentheses from the definition of sub GenerateClassInfo; then call it without the & prefix.

HTH,

Athanasius <°(((>< contra mundum

Comment on Re: dereferencing multiple hash array structure Download Code

Replies are listed 'Best First'.
Re^2: dereferencing multiple hash array structure by AnomalousMonk (Archbishop) on Jun 23, 2012 at 15:13 UTC
Using prototypes on subroutines is usually a bad idea... Further to Athanasius's point: The function `GenerateClassInfo` is prototyped to take zero arguments, but is defined as operating on a single argument. The only way this function can work as defined is to defeat the prototyping mechanism by calling the function with the `&` sigil. But what's the point of all that? Wasted motion of that sort is one of the reasons prototypes have a bad reputation. For far more, see Far More than Everything You've Ever Wanted to Know about Prototypes in Perl -- by Tom Christiansen. (Update: Furthermore, the `GenerateClassInfo` function is called before it is either defined or declared, i.e., before its prototype is available for checking. This would have generated a warning had the function not been called with the `&` sigil.)	[reply] [d/l] [select]

Replies are listed 'Best First'.

Re^2: dereferencing multiple hash array structure
by AnomalousMonk (Archbishop) on Jun 23, 2012 at 15:13 UTC

Using prototypes on subroutines is usually a bad idea...

Further to Athanasius's point: The function GenerateClassInfo is prototyped to take zero arguments, but is defined as operating on a single argument. The only way this function can work as defined is to defeat the prototyping mechanism by calling the function with the & sigil. But what's the point of all that? Wasted motion of that sort is one of the reasons prototypes have a bad reputation. For far more, see Far More than Everything You've Ever Wanted to Know about Prototypes in Perl -- by Tom Christiansen. (Update: Furthermore, the GenerateClassInfo function is called before it is either defined or declared, i.e., before its prototype is available for checking. This would have generated a warning had the function not been called with the & sigil.)

[reply]
[d/l]
[select]