Churro

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Churro is a stack-based interpreted programming language in which the code is entirely made up of churros. It was designed by Elliot Colp in 2014, who also wrote its interpreter. A compiler, Chlang, was written by Caian Benedicto in the same year.

Design principles

  • Churros are magical and should therefore be the only syntax element.
  • The language must include mutable state in order to irk Calvin Beck.

Language concepts

Churro operates on two structures: a stack and an array. Operations can only be directly performed on data in the stack. The array is used to store data which may need to be recalled later. The array is zero-indexed and all elements should be initialized to zero, though its exact size is implementation-defined.

Syntax

The only syntax elements are churros. A churro might look like this: {o}=====}

There are three important components to a churro:

  1. Its orientation -- either left or right
  2. Its filling -- either o (unfilled) or * (filled)
  3. Its tail length

A { always indicates the beginning of a churro. Any other characters between churros are ignored.

Literals

Left-facing churros, also known as "literal churros," represent data. When a literal churro is encountered, its value is pushed to the top of the stack.

The tail length of the churro -- that is, the number of = symbols -- is its numerical value. Sign is indicated by a churro's filling, with unfilled churros (o) being positive and filled churros (*) being negative. All data is stored as integers.

For example, this churro stands for 3: {o}===}

this churro stands for -9: {*}=========}

and this tiny one stands for 0: {o}}

Operators

Right-facing churros, also known as "operator churros," are used to manipulate data. They operate on values in the stack.

The functions are:

Churro Operation
{{o} pop A; discard A
{={o} pop A, B; push (B + A)
{=={o} pop A, B; push (B - A)
{==={o} pop A; if A = 0, jump to churro after matching occurence of {===={o}
{===={o} pop A; if A != 0, jump to churro after matching occurence of {==={o}
{====={o} pop A, B; store B in memory location A
{======{o} pop A; push the value in memory location A to stack
{======={o} pop A; print A as an integer
{========{o} pop A; print A as an ASCII character
{========={o} read a single character from stdin and push it to the stack
{=========={o} exit the program

The {==={o} and {===={o} operators are matched much like brackets in other programming languages, so they can be nested.

Filled operator churros have the same behaviour as unfilled churros, but instead of popping values on the stack, they peek them.

Style

Churros longer than a length of 10 have very little structural integrity, and so for the sake of realism, they should be avoided. Adding two smaller churros together is an acceptable solution.

Churros are also generally not stacked directly end-to-end, so leave a single space between each churro. To avoid churros being cut in half (the horror!) by console displays, keep lines below 80 characters in length.

In order to maintain the purity of the program's churro makeup, minimal (or no) comments are recommended. Of course, this may make code more difficult to read, so it is acceptable to distribute a "dirty" version of the code with comments and extra whitespace so long as a "pure" version with minimal whitespace is also included.

External resources