Tyl Process Module is used for running executable programs, also known as processes. These processes are programs that exist locally on the same machine that runs a Tyl program, and can handle tasks that Tyl does not support, or anyway are written already in another programming language and do them properly. Moreover, Tyl has the ability to run also an executable program that was created from a Tyl program.
Working with Single Process Modules
Declaration and initialization of single process module:
process 'state.reset.exe'
For process module the order of its variables is: path and arg, therefore, path will get the relative path of the program to be executed, will be referred to as the process.

In line process.execute, we call execute function of process module. execute causes the system to execute the process, and continue immediately with program execution, meaning it is done asynchronously.

This type of process execution is good for a launch and forget missions where we rely on the process to execute its tasks, and do not need to verify or get a result of its activities.

The second argument of process, is its process arguments. There are two types of arguments that process accepts: scalar and list. scalar argument means that the argument given is a scalar, and list means a list.

Say we have an addcalc process that does addition calculation, sqrtcalc that does square root calculation, and a calculator.tyl program that uses these processes:
! addcalc.exe
in0 number.of in 0
in1 number.of in 1
io.write 'add.result' in0 + in1
! sqrtcalc.exe
in0 number.of in 0
io.write 'sqrt.result' math.sqrt in0
! calculator.tyl
process 'sqrtcalc.exe' 10
acargs 10 20
process 'addcalc.exe' acargs
As described in working with executables page, input arguments come as string scalars, so we have to turn them into numbers, using number.of system function.

In calculator program there are two initialization lines of process. In each line, the first token is the module name 'process', meaning that process is a single module, also known as static or singleton. All access to its variables and functions will be in the format process.variable and process.function respectively.

In line process 'sqrcalc.exe' 10, we intialize process with the process and with the scalar argument 10. After execute, a result file 'sqrt.result' is created. In line process 'addcalc.exe' acargs, we give a predefined acargs list as the list argument. After execute, file 'add.result' is created.

All these executions are executed asynchronously, and the result files are created in the background.

If it is necessary to verify process execution, or anyway get a result of it, we use run execution function:
process 'state.get.exe'
result process.run
run function causes the system to wait until process execution is finished. run result will be the output of the process, in case of a successful execution, or a system error message. If there is no output from the process, the result will be an empty string.

This type of process execution is called a synchronous operation, and it gives you the ability to proceed with program execution, based on the result of the execution.