dat file parser gives unhelpful message for two-dimensional set input

[DLWoodruff]

2dDat.zip
The attached example has a 2d set with the correct syntax for AMPL in the dat file, but this is the
result (at a minimum the message should indicate that it comes from the dat file parser).

$ pyomo solve 2dDAT.py 2dDAT.dat --solver=cplex

[ 0.00] Setting up Pyomo environment
[ 0.00] Applying Pyomo preprocessing actions
[ 0.00] Creating model
[ 0.02] Pyomo Finished
ERROR: Unexpected exception while running model: Unexpected comma outside of
(), {} or [] declarations

[mrmundt]

@DLWoodruff @blnicho - I'm going through old bug reports. Is this bug still present in the most recent Pyomo version?

[mrmundt]

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