Torch, how to execute a script with "dofile" and input parameters?

Question

I'm executing a Torch script from my Linux shell, with the th command. This Torch script takes two input parameters:

th torch_script.lua input_parameter1 input_parameter2

Now I'd like to run this script through the Torch shell. To do this, I have to use the dofile command. But in this case, I don't know how to pass the input parameters input_parameter1 and input_parameter2.

In Torch, how to pass some input parameters to the dofile execution command?

---

EDIT: Here's the code that I'm trying to run. I'm not able to run it properly, maybe you can tell me why

external_command.lua content:

local arg = arg or {...} 
input_parameter = arg[1]
print("input_parameter ".. input_parameter);

On the shell:

$th
th> tempFunc = load "external_command.lua"
th> tempFunc("try")
[string "_RESULT={tempFunc("try")}"]:1: attempt to call global 'tempFunc' (a nil value)
stack traceback:
    [string "_RESULT={tempFunc("try")}"]:1: in main chunk
    [C]: in function 'xpcall'
    /home/davide/torch/install/share/lua/5.1/trepl/init.lua:630: in function 'repl'
    ...vide/torch/install/lib/luarocks/rocks/trepl/scm-1/bin/th:185: in main chunk
    [C]: at 0x004064d0  

---

EDIT 2: I tried the solution posted by TonyHsu, but it does not work anyway. Here's what I'm doing.

I define a function runfile() in a script called runfile.lua which contains the following code:

function runfile(scriptName, input)
  opt = nil
  arg = input
  dofile(scriptName)
end

Then I use the external_command.lua script that I previously defined as scriptName input parameter for this function:

th> scriptName = "external_command.lua"
th> require './runfile.lua'
th> runfile(scriptName, "Hello world");

Unfortunately, also in this case I get an error:

external_command.lua:4: attempt to concatenate global 'input_parameter' (a nil value)
stack traceback:
    external_command.lua:4: in main chunk
    [C]: in function 'dofile'
    /home/davide/torch/temp/runfile.lua:4: in function 'runfile'
    [string "runfile(scriptName, "Hello world");"]:1: in main chunk
    [C]: in function 'xpcall'
    /home/davide/torch/install/share/lua/5.1/trepl/init.lua:648: in function 'repl'
    ...vide/torch/install/lib/luarocks/rocks/trepl/scm-1/bin/th:185: in main chunk
[C]: at 0x004064d0  

Answer 1

I think the trick is to pass the parameters in global variable 'args'. Say, I have the following content in external_command.lua.

-- args has been set by the caller
if not args or #args == 0 then
    print('no input_parameter')
else
    print('#args = ' .. #args, 'input_parameter: ' .. args[1])
end

Then define runfile() as follows.

function runfile(f, ...)
    local tmp = args  -- save the original global args
    args = table.pack(...)
    dofile(f)
    args = tmp  -- restore args
end

I've tested it in th. It looks like this.

th> runfile('ext_command.lua', 10)
#args = 1       input_parameter: 10
                                                                      [0.0002s]
th> runfile('ext_command.lua', 'a', 'b', 'c')
#args = 3       input_parameter: a
                                                                      [0.0002s]