Chef interpreter written in Python

This is a simple chef interpreter written in Python. It is based on the esolangs.org page for the chef language. You can find the page here.

Usage

To run the interpreter, simply run the chef.py file with the path to the chef file as an argument. For example:

python chef.py examples/hello_world.chef

Learning chef

Chef is a simple esoteric programming language that is based on cooking. The language is based on the idea of a chef preparing a meal. The program is a recipe, and the data is the ingredients. The program is divided into a list of recipes, and each recipe is divided into a list of ingredients. The ingredients are then prepared and mixed together to create the final dish.

Language concepts

• Ingredients: The ingredients hold the data in the program. All ingredients are numerical, and they can be either dry or liquid. Liquid ingredients will be outputted as Unicode characters, while dry ingredients will be outputted as numbers.

• Mixing bowl: Chef has access to unlimited mixing bowls and baking dishes. Mixing bowls or baking dishes can contain ingredients values. The ingredients inside a mixing bowl or baking dish are ordered in the form of a stack. Note that if the value of an ingredient changes, the value inside the baking dish or mixing bowl will not change. Multiple mixing bowls or baking dishes can be used by being referred to by an ordinal identifier - "the 2nd mixing bowl". If no ordinal identifier is given, chef interprets it as we are only using one mixing bowl.

Syntax Elements

The following items appear in a Chef recipe. Some are optional. Items must appear in the order shown below, with a blank line (two newlines) between each item.

NOTE. Remember that between each component of the recipe, there must be 2 newlines, this is mandatory for the interpreter to work, also, at the end of the document, there must be two newlines.

• Recipe Title: The name of the recipe. This always should appear at the first line of the recipe.

Recipe Name.

• Comments: Comments are ignored by the interpreter. They come in paragraph form right after the recipe title.

• Ingredients List: Ingredients are listed one per line. The intial-value is a number, and is optional. Attempting to use an ingredient without a defined value is a run-time error. The optional measure can be any of the following:

  • g | kg | pinch[es] : These always indicate dry measures.
  • ml | l | dash[es] : These always indicate liquid measures.
  • cup[s] | teaspoon[s] | tablespoon[s] : These indicate measures which may be either dry or liquid.

  The optional measure-type may be any of the following:

  • heaped | level : These indicate that the measure is dry.

  The ingredient-name may be anything reasonable, and may include space characters. The ingredient list is mandatory. It declares ingredients with the given initial values and measures. If an ingredient is repeated, the new vaue is used and previous values for that ingredient are ignored

Ingredients.
[initial-value] [[measure-type] measure] ingredient-name
[further ingredients]

• Cooking time: The cooking time is the number of minutes the recipe should be cooked for. This is optional.

 Cooking time: time (hour[s] | minute[s]).

• Oven temperature: Some recipes require baking. If so, there will be an oven temperature statement. This is optional. The temperature and mark are numbers.

 Pre-heat oven to temperature degrees Celsius [(gas mark mark)].

• Method: The method is the main part of the recipe. It is a list of instructions. Each instruction is a sentence. The instructions are executed in order.

Method.
method-instruction.

Here is a list of the possible method instructions:

• Take ingredient from refrigerator. This reads a numeric value from STDIN into the ingredient named, overwriting any previous value.

• Put ingredient into [nth] mixing bowl. This puts the ingredient into the nth mixing bowl.

• Fold ingredient into [nth] mixing bowl. This removes the top value from the nth mixing bowl and places it in the ingredient.

• Add ingredient [to [nth] mixing bowl]. This adds the value of ingredient to the value of the ingredient on top of the nth mixing bowl and stores the result in the nth mixing bowl.

• Remove ingredient [from [nth] mixing bowl]. This subtracts the value of ingredient from the value of the ingredient on top of the nth mixing bowl and stores the result in the nth mixing bowl.

• Combine ingredient [into [nth] mixing bowl]. This multiplies the value of ingredient by the value of the ingredient on top of the nth mixing bowl and stores the result in the nth mixing bowl.

• Divide ingredient [into [nth] mixing bowl]. This divides the value of ingredient into the value of the ingredient on top of the nth mixing bowl and stores the result in the nth mixing bowl.

• Add dry ingredients [to [nth] mixing bowl]. This adds the values of all the dry ingredients together and places the result into the nth mixing bowl.

• Liquefy | Liquify ingredient. This turns the ingredient into a liquid, i.e. a Unicode character for output purposes. (Note: The original specification used the word "Liquify", which is a spelling error. "Liquify" is deprecated. Use "Liquefy" in all new code.)

• Liquefy | Liquify contents of the [nth] mixing bowl. This turns all the ingredients in the nth mixing bowl into a liquid, i.e. a Unicode characters for output purposes.

• Stir [the [nth] mixing bowl] for number minutes. This "rolls" the top number ingredients in the nth mixing bowl, such that the top ingredient goes down that number of ingredients and all ingredients above it rise one place. If there are not that many ingredients in the bowl, the top ingredient goes to tbe bottom of the bowl and all the others rise one place.

• Stir ingredient into the [nth] mixing bowl. This rolls the number of ingredients in the nth mixing bowl equal to the value of ingredient, such that the top ingredient goes down that number of ingredients and all ingredients above it rise one place. If there are not that many ingredients in the bowl, the top ingredient goes to the bottom of the bowl and all the others rise one place.

• Mix [the [nth] mixing bowl] well. This randomises the order of the ingredients in the nth mixing bowl.

• Clean [nth] mixing bowl. This removes all the ingredients from the nth mixing bowl.

• Pour contents of the [nth] mixing bowl into the [pth] baking dish. This copies all the ingredients from the nth mixing bowl to the pth baking dish, retaining the order and putting them on top of anything already in the baking dish.

• Verb the ingredient. This marks the beginning of a loop. It must appear as a matched pair with the following statement. The loop executes as follows: The value of ingredient is checked. If it is non-zero, the body of the loop executes until it reaches the "until" statement. The value of ingredient is rechecked. If it is non-zero, the loop executes again. If at any check the value of ingredient is zero, the loop exits and execution continues at the statement after the "until". Loops may be nested.

• Verb [the ingredient] until verbed. This marks the end of a loop. It must appear as a matched pair with the above statement. verbed must match the Verb in the matching loop start statement. The Verb in this statement may be arbitrary and is ignored. If the ingredient appears in this statement, its value is decremented by 1 when this statement executes. The ingredient does not have to match the ingredient in the matching loop start statement.

• Set aside. This causes execution of the innermost loop in which it occurs to end immediately and execution to continue at the statement after the "until".

• Serve with auxiliary-recipe. This invokes a sous-chef to immediately prepare the named auxiliary-recipe. The calling chef waits until the sous-chef is finished before continuing. See the section on auxiliary recipes below.

• Refrigerate [for number hours]. This causes execution of the recipe in which it appears to end immediately. If in an auxiliary recipe, the auxiliary recipe ends and the sous-chef's first mixing bowl is passed back to the calling chef as normal. If a number of hours is specified, the recipe will print out its first number baking dishes (see the Serves statement below) before ending.

• Serves: The final statement in a Chef recipe is a statement of how many people it serves.

 Serves number-of-diners.

This statement writes to STDOUT the contents of the first number-of-diners baking dishes. It begins with the 1st baking dish, removing values from the top one by one and printing them until the dish is empty, then progresses to the next dish, until all the dishes have been printed. The serves statement is optional, but is required if the recipe is to output anything!

• Auxiliary recipes: These are small recipes which are needed to produce specialised ingredients for the main recipe (such as sauces). They are listed after the main recipe. Auxiliary recipes are made by sous-chefs, so they have their own set of mixing bowls and baking dishes which the head Chef never sees, but take copies of all the mixing bowls and baking dishes currently in use by the calling chef when they are called upon. When the auxiliary recipe is finished, the ingredients in its first mixing bowl are placed in the same order into the calling chef's first mixing bowl.

  For example, the main recipe calls for a sauce at some point. The sauce recipe is begun by the sous-chef with an exact copy of all the calling chef's mixing bowls and baking dishes. Changes to these bowls and dishes do not affect the calling chef's bowls and dishes. When the sous-chef is finished, he passes his first mixing bowl back to the calling chef, who empties it into his first mixing bowl.

  An auxiliary recipe must only have the 3 main components, the name, the ingredients list, and the method.