Initializing a multidimensional associative array

SystemVerilog
2

Two things you need to do:

  1. The index:value syntax is an assignment pattern, so you must use '{index:value}, so it does not look like a concatenation.
  2. Each dimension of an array has to be properly nested
string ARY[string][string] = '{"A":'{"0":"abc", "1":"def"}, "B":'{"0":"ghi"}};

If ordering your array elements this way does not make sense for your situation, then an assignment for each individual element might be the most readable.