Chef Interpreter

A Python interpreter for the Chef esoteric programming language, where programs are written as cooking recipes.

Installation

Requires Python 3.10+. No external dependencies.

pip install .

This installs the cook command globally (or into the active virtualenv).

Usage

cook <recipe.chef>

Pipe input for programs that use Take ... from refrigerator:

echo "5" | cook examples/interactive_factorial.chef

Language Overview

Chef is a stack-based language designed by David Morgan-Mar (2002). Programs look like cooking recipes: variables are ingredients, stacks are mixing bowls, and output buffers are baking dishes.

• Dry ingredients (g, kg, pinches) output as numbers.
• Liquid ingredients (ml, l, dashes) output as Unicode characters.
• Mixing bowls are LIFO stacks for computation.
• Baking dishes accumulate output. The Serves statement prints them.

Supported Instructions

Data

Arithmetic

All arithmetic operates on the top of the specified mixing bowl.

Bowl / Dish Operations

Control Flow

Output

Ingredient Format

Each ingredient is one line in the Ingredients. section:

[initial-value] [[measure-type] measure] ingredient-name

• initial-value (optional): a non-negative integer. Omit for ingredients set later via Take or Fold.
• measure-type (optional): heaped or level (forces dry).
• measure (optional): determines dry/liquid type.
  • Dry: g, kg, pinch, pinches
  • Liquid: ml, l, dash, dashes
  • Either: cup(s), teaspoon(s), tablespoon(s)
• ingredient-name: any string (may contain spaces).

Auxiliary Recipes

Auxiliary recipes are listed after the main recipe's Serves statement. Each has its own title, ingredients, and method. They act as subroutines invoked by Serve with recipe-name.

When called:

1. The sous-chef receives deep copies of all the caller's mixing bowls and baking dishes.
2. The sous-chef executes using its own ingredients.
3. On completion, the sous-chef's 1st mixing bowl is transferred back to the caller's 1st mixing bowl.

Auxiliary recipes can call other auxiliary recipes (or themselves recursively).

Example Programs

hello.chef — String Output

Pushes ASCII values as liquid ingredients and prints Hi!.

cook examples/hello.chef
# Hi!

factorial.chef — Loops and Arithmetic

Computes 5! = 120 using a loop with Combine (multiply) and Fold (store result).

cook examples/factorial.chef
# 120

calculator_cake.chef — Mixed Output

Reads a number, computes its factorial, and prints N! = result by combining liquid characters (! = ) with dry numeric values across three baking dishes.

echo "5" | cook examples/calculator_cake.chef
# 5! = 120

prompted_factorial.chef — Mid-Execution Output

Uses Refrigerate for 1 hour to flush the prompt Enter a number: to stdout before reading input.

echo "7" | cook examples/prompted_factorial.chef
# Enter a number: 7! = 5040

fibonacci.chef — Auxiliary Recipes

Computes the first 8 Fibonacci numbers using an addition broth auxiliary recipe that receives two values via the mixing bowl, computes their sum, and returns the result.

cook examples/fibonacci.chef
# 13
# 8
# 5
# 3
# 2
# 1
# 1
# 0

Development

Running Tests

pip install pytest
pytest

Project Structure

chef-lang/
├── chef_lang/
│   ├── __init__.py          # Package exports
│   └── interpreter.py       # The interpreter
├── examples/                # Example .chef programs
│   ├── hello.chef
│   ├── appetit.chef
│   ├── factorial.chef
│   ├── interactive_factorial.chef
│   ├── calculator_cake.chef
│   ├── prompted_factorial.chef
│   └── fibonacci.chef
├── tests/
│   └── test_interpreter.py  # Test suite
├── LICENSE
├── README.md
└── pyproject.toml

Spec Deviations

• Refrigerate in main recipe: when called with for N hours, prints N dishes and continues execution (rather than halting). Without hours, halts as per spec. This enables mid-execution output (prompts before input).
• Method line breaks: instructions must be one per line. The spec says line breaks are ignored (sentences delimited by periods), but all known Chef programs use one instruction per line.
• Serves output order: prints dish 1 first through dish N. The spec is ambiguous on order; some interpreters reverse it.