Use .get() in MultiD Assoc Array?

[Ali Çehreli]

On 08/31/2012 08:56 AM, Paul wrote:
 >> You're welcome. Note that your need of having a structure which is
 >> both associative and ordered is, if not unheard-of, at least somewhat
 >> uncommon.
 >
 > I'm parsing program blocks from a proprietary HW/SW system. They provide
 > the data in the form of:
 >
 > Somegroupname/Someblockname
 > someparam=value
 > anotherparam=value
 > ...
 > otherparam=value
 > end
 >
 > Somegroupname/Somediffblockname
 > someparam=value
 > anotherparam=value
 > ...
 > otherparam=value
 > end
 >
 > Someothergroupname/Someotherblockname
 > p1=value
 > p2=value
 > ...
 > px=value
 > end
 >
 > The data is in an ascii text file.
 > I need to be able to search it by group/block/parameter.
 > I need to be able to maintain group/block order.
 > There are ~hundred diff block types where the params and order of params
 > are known...though I would rather not create all of these structures or
 > lists ahead of time.
 >
 > My greatest need at this point is to compare two files block by block.
 > The blocks may be in diff orders between the files but the params of
 > each block type would always be the same in the same order.
 >
 > So compare groups, blocks within groups, and the values of each param
 > for matching group/block names.

Wrap your string[string][string][string] in a user-defined type that 
provides "the 'in' operator" as well as opIndex and friends. I have 
started writing this but could not finish it yet:

import std.exception;

class MyTable
{
     string[string][string][string] elements;

     struct Index
     {
         string i0;
         string i1;
         string i2;
     }

     // Enables the 'auto element = myIndex in myTable' syntax
     // (Note: I should have called it Key, not Index.)
     string * opBinary(string op)(Index index)
         if (op == "in")
     {
         string * result = null;

         if (auto table0 = index.i0 in elements) {
             if (auto table1 = index.i1 in *table0) {
                 if (auto element = index.i2 in *table1) {
                     result = element;
                 }
             }
         }

         return result;
     }

     // Enables 'auto value = myTable[myIndex]'
     ref string opIndex(Index index)
     {
         string * result = this.opBinary!"in"(index);
         enforce(result);

         return *result;
     }

     // Enables 'myTable[myIndex] = value'
     void opIndexAssign(string value, Index index)
     {
         auto existing = this.opIndex(index);

         if (existing) {
             existing = value;

         } else {
             // TODO: ensure that this Index exists
         }
     }

     // TODO: Look up oopIndexUnary and opIndexOpAssign

     string get(Index index, string defaultValue)
     {
         string * result = this.opBinary!"in"(index);
         return result ? *result : defaultValue;
     }
}

void main()
{}

Ali