clox

Quick Start

make -- Builds the project

make run NAME=../samples/fib.lox -- Builds the project and runs a script.

make repl -- Builds the project and fires up the REPL.

Dependencies

• A C compiler (gcc or clang should work fine)
  • Most OS provide easy ways to install a C compiler (e.g., in Debian-based distributions, apt install build-essentials installs gcc)
• GNU make to build the project.
  • It's important to ensure that it's GNU make and not some other implementation since we're using specific features from that version.

Building and Running Tests

We don't have tests for clox yet :-(

Running the REPL

If you want to test single-line commands in clox, you can run its REPL as follows:

make repl

When you're done with it, you can type quit to exit the REPL.

Debugging

The REPL also supports a few directives to ease debugging of code:

• :load <file-path>
  • loads a Lox file into the current session (absolute and relative paths are supported), e.g., :load ../test.lox should work.
• :toggle-tracing
  • turns on/off execution tracing of any statement/expression you evaluate
• :toggle-bytecode
  • turns on/off the automatic display of bytecode generated for the last statement/expression you typed.
• :gc-stats
  • prints basic statistics about memory allocation and garbage collection.
• :gc
  • forces a garbage collection run.

Also, if you want any of these settings to be automatically activated (they're both turned off by default), you can write a settings file .loxrc in the current working directory¹ (i.e., the directory you're launching clox from):

# this will make the REPL show bytecode by default but not execution tracing
:show-bytecode
#:enable-tracing

Running Individual Scripts

Note that the REPL only supports single-line strings, so if you want to test something larger, your best bet is to put it in a script and run it as follows:

make run NAME=../samples/fib.lox

Issues

Footnotes

1. We have a pending issue to make this work when having .loxrc in your home directory, or on any ancestor path starting from the current working directory. ↩