Calling Mathics library from within Python code

Mathics is also a Python library implementing a parser and a interpreter for WL.

For single line code, one stright forward way to interpret, evaluate a WL expression, and obtaint a simple (text) formatted output is by means of a system call

import subprocess

expression = "Integrate[Sin[x]/x,x]"
cmd = ["mathics", "--no-completion", "-q", "--colors", "NOCOLOR"]
result = subprocess.run(cmd.append(f"\"{expression}\"" )], stdout=subprocess.PIPE).stdout
result = result.split("\n")[-1]
result = result[result.find("=")+1:]

This code runs the Mathics interpreter as a subprocess, sending a the expression as an input parameter, and extracts from the output the result.

On the other hand, we can do this best by calling directly to the library:

from mathics.session import MathicsSession
session = MathicsSession(add_builtin=True, catch_interrupt)


expression = 'Integrate[Sin[x]/x,x]'
result = session.evaluate(expression)
session.evaluation.format_output(result)