stlox is an interpreter of the Lox programming language as described in the excellent Crafting Interpreters book by Robert Nystrom. It is a tree-walk interpreter written in Smalltalk, based directly on the Java version described in the book.

Installation and usage

GNU Smalltalk

Requires GNU Smalltalk, which can be installed by downloading and unpacking the latest stable/alpha version from the GNU FTP site:

# download and unpack source
wget https://alpha.gnu.org/gnu/smalltalk/smalltalk-3.2.91.tar.xz
tar -xvf smalltalk-3.2.91.tar.xz
cd smalltalk-3.2.91

# compile and install
export CFLAGS="-no-pie"
export LDFLAGS="-no-pie"
./configure
make
make install

This should create the Smalltalk interpreter gst (and other useful tools like gst-load for using packages) installed by default at /usr/local/bin.

Alternatively you may find that GNU Smalltalk is available in your system's package manager.

Lox

The Lox interpreter can be installed using the provided Makefile:

git clone https://github.com/lewis-weinberger/stlox.git
cd stlox
make install
make test # optionally run tests

This will place an executable script stlox at /usr/local/bin (by default) which can be used to run the interpreter:

# run as interactive interpreter by passing no arguments
stlox

# read and interpret from source file by passing file path
stlox examples/helloworld.lox

There are some Lox examples in the examples subdirectory.

Status

Following the order in the book, the following has been implemented so far:

• Scanner
• Parser
• Interpreter:
  • Expressions
  • Statements
  • Control flow
  • Functions
  • Variable binding
  • Classes
  • Inheritance
• Tests

License

MIT