[QSF] sourcing a tcl file actually copy its context inside to QSF. Why?

Hi All,

I want to list the Project RTL files in the separate TCL file and then source it from QSF.

Here is an example of my TCL file:

set RTL_DIR "D:/units/bit/rtl"
set_global_assignment -library bit_mgr -name QIP_FILE ${RTL_DIR}/fifo/fifo_flr/fifo_flr.qip
set_global_assignment -library bit_mgr -name VHDL_FILE  ${RTL_DIR}/pkgs/func/f_and2.vhd
set_global_assignment -library bit_mgr -name VHDL_FILE  ${RTL_DIR}/pkgs/func/f_int.vhd
...

Here is how I source this file inside of QSF:

source rtl_files.tcl

But, instead just sourcing this tcl file, Quartus actually copy its contents to QSF. Why?

How can I make Quartus to source the tcl file rather than to copy its contents into QSF?

Thank you!