fix array_var to handle empty tables
fix array_var to handle empty tables

mwest1066/PrairieLearn,mwest1066/PrairieLearn,tbretl/PrairieLearn,rbessick5/PrairieLearn,parasgithub/PrairieLearn,parasgithub/PrairieLearn,rbessick5/PrairieLearn,jakebailey/PrairieLearn,rbessick5/PrairieLearn,mwest1066/PrairieLearn,jakebailey/PrairieLearn,parasgithub/PrairieLearn,rbessick5/PrairieLearn,parasgithub/PrairieLearn,parasgithub/PrairieLearn,tbretl/PrairieLearn,jakebailey/PrairieLearn,tbretl/PrairieLearn,mwest1066/PrairieLearn,tbretl/PrairieLearn,mwest1066/PrairieLearn,tbretl/PrairieLearn,jakebailey/PrairieLearn,rbessick5/PrairieLearn