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.
- Program recipes should not only generate valid output, but be easy to prepare and delicious.
- Recipes may appeal to cooks with different budgets.
- Recipes will be metric, but may use traditional cooking measures such as cups and tablespoons.
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.
Mixing Bowls and Baking Dishes
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
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:
[initial-value] [[measure-type] measure] ingredient-name
The optional measure-type may 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 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.
heaped | level : These indicate that the measure is dry.
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.
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 tbe 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.
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.
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.
Chef on the Net
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Last updated: Thursday, 12 February, 2015; 22:54:12 PST.
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