Complete the main program that inputs a BL program from an input stream in$,$ and outputs the

compiled program to an output stream out. If there are any syntax errors in the input, the compiler

will report the first one it encounters and quit. If the input is a valid BL program, the compiler will

output the compiled program one integer per line starting with an integer that is the length of the

compiled program $($the number of BL virtual machine memory locations the compiled program

needs$).$

Here is a reminder of the general structure of the compiler: