Chef is a programming language in which programs look like recipes.
NEW: Additional syntax specifications added 17 July, 2003, marked in red. Fixed spelling of "liquefy" keyword.
All recipes have ingredients! The ingredients hold individual data values. All ingredients are numerical, though they can be interpreted as Unicode for I/O purposes. Liquid ingredients will be output as Unicode characters, while dry or unspecified ingredients will be output as numbers.
Chef has access to an unlimited supply of mixing bowls and baking dishes. These can contain ingredient values. The ingredients in a mixing bowl or baking dish are ordered, like a stack of pancakes. New ingredients are placed on top, and if values are removed they are removed from the top. Note that if the value of an ingredient changes, the value in the mixing bowl or baking dish does not. The values in the mixing bowls and baking dishes also retain their dry or liquid designations.
Multiple mixing bowls and baking dishes are referred to by an ordinal identifier - "the 2nd mixing bowl". If no identifier is used, the recipe only has one of the relevant utensil. Ordinal identifiers must be digits followed by "st", "nd", "rd" or "th", not words.
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.
The recipe title describes in a few words what the program does. For example: "Hello World Souffle", or "Fibonacci Numbers with Caramel Sauce". The recipe title is always the first line of a Chef recipe, and is followed by a full stop.
Comments are placed in a free-form paragraph after the recipe title. Comments are optional.
The next item in a Chef recipe is the ingredient list. This lists the ingredients to be used by the program. The syntax is
[initial-value] [[measure-type] measure] ingredient-name
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 optional. If present, 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.
Cooking time: time (hour[s] | minute[s]).
The cooking time statement is optional. The time is a number.
Pre-heat oven to temperature degrees Celsius [(gas mark mark)].
Some recipes require baking. If so, there will be an oven temperature statement. This is optional. The temperature and mark are numbers.
The method contains the actual recipe instructions. These are written in sentences. Line breaks are ignored in the method of a recipe. Valid method instructions are:
Take ingredient from refrigerator.
Put ingredient into [nth] mixing bowl.
Fold ingredient into [nth] mixing bowl.
Add ingredient [to [nth] mixing bowl].
Remove ingredient [from [nth] mixing bowl].
Combine ingredient [into [nth] mixing bowl].
Divide ingredient [into [nth] mixing bowl].
Add dry ingredients [to [nth] mixing bowl].
Liquefy | Liquify ingredient.
Liquefy | Liquify contents of the [nth] mixing bowl.
Stir [the [nth] mixing bowl] for number minutes.
Stir ingredient into the [nth] mixing bowl.
Mix [the [nth] mixing bowl] well.
Clean [nth] mixing bowl.
Pour contents of the [nth] mixing bowl into the [pth] baking dish.
Verb the ingredient.
Verb [the ingredient] until verbed.
Serve with auxiliary-recipe.
Refrigerate [for number hours].
The final statement in a Chef recipe is a statement of how many people it serves.
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!
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 may have all the same items as a main recipe.