pyterpreter

Python interpreter built on Truffle and Graal VM

Features

Types

• int (arbitrary precision)
• str
• bool

Operators

• arithmetic (+, -, *, /, %)
• assignment (=, +=, -=, *=, /=, %=)
• comparison (==, !=, >, >=, <, <=)
• logical (not, and, or)

Flow control

• if/else (no elif)
• while loop (no for)

Functions

• function definition, arbitrary argument number (only positional, no named)
• function nesting, recursion
• no pass blank statement
• builtin functions:
  • x = str(arg) - convert arg to string type
  • x = int(arg) - convert arg to int type
  • print(arg) - print arg to console (with newline)
  • x = input() - read user input from console, assign to variable
  • sleep(seconds) - sleep for given number of seconds
  • exit() - exit the program
  • x = time() - get millisecond-precision time
    • Not actual clock time, but good for measuring elapsed time
    • Similar to Python's time.time() but Pyterpreter cannot do imports so there we go
    • For compatibility in running pyterpreter scripts in Python, user a wrapper script where you import time(), e.g. from time import time; import pyterpreter_script.py

Examples

• Some scripts that Pyterpreter can handle are in the benchmark folder

Installation

Requirements

• JVM (tested on 8)
  • It will work on regular HotspotVM
  • For better performance run on GraalVM (Linux/MAC)
    • Download labsjdk on bottom of the page
    • Set JAVA_HOME to point to extracted LabsJDK archive and PATH to JAVA_HOME/bin
• Gradle will be used or automatically downloaded when running gradlew (see below)
• In order to run Pyterpreter on Graal, copy or symlink Graal root directory to pyterpreter/graalvm (download on the same URL as above, but use the links on the top of the page)

Steps

$ git clone git@github.com:melkamar/pyterpreter.git
$ cd pyterpreter
$ ./gradlew clean test jar

Usage

$ ./pyterpreter [args]  # Non-graal
$ ./pyterpreter-graal [args]  # Graal-enabled

• No arguments - start REPL
• Single argument - path to file - execute that file
• -r file/in/resources - run file from inside pyterpreter jar. See resources folder
  • e.g. java -jar build/libs/pyt*all* -r benchmark/fibonacci.py will start fibonacci benchmark.

Numbers

Using benchmark countdown.py, in milliseconds

• Hotspot 1722/356
• Graal 2627/438

:(