Python wrapper for Python program

Question

I'm looking for a way to create a Python program that wraps another Python program. This is what I mean:

while (otherProgram is waiting for raw_input):
 send some text to the other program

It is essential that I can do this in two separate programs.

Here is another example:

program1.py

text = raw_input()
print("You entered " + text)
text2 = raw_input()
print("Your second input was " + text2)
text3 = raw_input()
print("Your third input was " + text3)

program2.py

# use program1.py somehow
while program1_is_waiting_for_input:
 send_to_program1("prefix " + raw_input() + " suffix")

sample input into program2:

asdf
ghjkl
1234

sample output out of program2:

You entered prefix asdf suffix
Your second input was prefix ghjkl suffix
Your third input was prefix 1234 suffix

Things I have considered using:

• I don't think eval or exec or anything like that would work, since I don't know how much code to execute.
• The subprocess module might work if I pipe the outputs correctly, but can I "pause" the second program when waiting for input?
• Maybe I should try to multithread the non-wrapper program, but I don't know how I would go about doing that
• Download an open-source python interpreter and try to work off that (seems overly difficult for a relatively simple problem)

What I hope to end up with

I eventually want to end up with a Python program which, each time it is run, inserts another successive input into the wrapped program at the point it left off, and pipes the output into stdout. If it is easier to do this, that would be great.

• thefourtheye: I am not very sure, but you might want to look at gevent module.
• Blender: Why can't you import components from that other script?
• Janne Karila: What do you mean by "pausing" the second program?
• icedtrees: @Blender I can't be sure of the format of the script, or the order of the code that is executed. I need to specifically pipe through input in the order specified by the raw_input()s in the wrapped program
• icedtrees: @JanneKarila I mean that the wrapped program stops its execution and waits for input from the wrapper program to continue.

Answer 1

Here is an example of running the child process using subprocess.

import subprocess
program1 = subprocess.Popen("program1.py", stdin=subprocess.PIPE, stdout=subprocess.PIPE)
while program1.poll() == None:
 cmd_to_send = "prefix " + raw_input() + " suffix"
 program1.stdin.write(cmd_to_send + "\n")

Your child process will wait for input because raw_input is a blocking call until it receives a line of input.

Answer 2

take a look at subprocess module or https://pypi.python.org/pypi/pexpect-u/

• icedtrees: pexpect was what I was looking for. gevent looks good for the successive inputs idea