lil-dolbaeb

Esoteric Programming Language

Description

Lil Dolbaeb is an esoteric programming language. It is turing complete, support I/O operations and has a rather simple syntax.

File extensions: .lil, .ld

Syntax

In Lil Dolbaeb, every UTF-8 symbol is a function. A function has a predefined amount of arguments. The language is parsed by the the rules of Polish Notation.

There are some predefined functions and new functions may be created.

The parser consumes one functions at a time, executes it and then repeats the process until no more functions can be consumed. This allows functions to have dynamic amount of arguments after (re-)defining functions.

The language has neither variables nor some kind of stack. Instead it offers two global values called last and args.

Most functions don't modify these values, but can access them. Some functions however have "side effects" which will modify the values.

Any value in Lil Dolbaeb is saved internally as a semi-list, which can be in one of four states:

Empty list
A single number
A list of numbers of any length
A list of numbers or lists - definition apply recursively

The values may be interpreted in two ways:

A list
A number

The conversion between these types is done internally and can not be directly accessed. Following rules apply:

When number is expected:
- Empty list turns into zero
- A single number is used directly
- A list of numbers returns the last number
- A recursive list takes the last element and applies the same rules as listed here
When a list is expected:
- Empty list, list of numbers or recursive list are used directly
- A single number is used as a one-element-long list

Functions are interpreted one after another. Whenever a function on the global level is executed, last is set to its' return value.

When the program starts to execute, last is an empty list and args is a one level recursive list of the program arguments with first element being the file name of the program. For example calling python execute.py test.lil first "second argument" will result in args := [[116, 101, 115, 116, 46, 108, 105, 108], [102, 105, 114, 115, 116], [115, 101, 99, 111, 110, 100, 32, 97, 114, 103, 117, 109, 101, 110, 116]].

I/O

Lil Dolbaeb has 4 internal values to keep track of I/O operations.

outputs - list of open("w") streams
outputi - index of the output currently operating on
inputs - list of open("r") streams
inputi - index of the input currently operating on

When starting the program following values are already available:

outputs: stdout and stderr
outputi: zero
inputs: stdin
inputi: zero

When reading, EOF is signaled through the value -1.

Functions

Newlines are ignored.

Number

One of:

0 1 2 3 4 5 6 7 8 9

No arguments. Return the respectively selected number.

Add

Two arguments. Add two numbers.

Sub

Two arguments. Subtract 2nd from the 1st number.

Mul

Two arguments. Multiply two numbers.

Div

Two arguments. Divide 1st number by the 2nd. The 2nd value is only executed if 1st value is not equal to zero. Dividing by zero produces zero. The result is a whole number.

Last

No arguments. Return last.

Args

No arguments. Return args.

Def

Three arguments. (Re-)define a function.

The function name

If this function was already defined earlier or is a builtin function, you have to supply dummy arguments for the parser to parse the code correctly.

Number of arguments

Expects a number

Code to execute when the function is called

Side effects:

calling a self defined function sets args to a list of the return values from the passed arguments

Return the number of arguments.

Write

One argument. Write a character with the numerical value equal to the provided number to the selected output.

Read

No arguments. Read one character from selected input, convert it to a numerical value and return it.

Write Index

¡

One argument. Set outputi to the provided value modulo the length of outputs. Return the value.

Read Index

¿

One argument. Set inputi to the provided value modulo the length of inputs. Return the value.

Open Write

No arguments. Create a new write stream to the file, whose location is saved as an array of character values in last. Return the new length of outputs.

Open Read

No arguments. Create a new read stream from the file, whose location is saved as an array of character values in last. Return the new length of inputs.

Close Write

°

No arguments. Close and remove the selected output. Return the new length of outputs.

Close Read

No arguments. Close and remove the selected input. Return the new length of inputs.

Concat

One argument. Concatenate last with the provided list and return it.

Iter

Two arguments. Iterate over a list.

The list to iterate over
Function to use for iterating

Side effects and order of execution:

Execute 1st argument to get the list
Set args and last to empty lists
Before each iteration args is set to the element which is currently being iterated over
Execute 2nd argument
After each iteration last is set to the return value

Return the last return value.

While

Three arguments. Execute as long as two values are not equal.

Function to compare
Value to compare
Function to execute

Side effects and order of execution:

Execute 2nd argument
Execute 1st argument and compare it to the result; if they are equal, exit the loop
Execute 3rd argument
Set last to the return value and go to step 2

Get

Two arguments. Get an element from a list by the index. Works like python's indexing where negative index takes elements from the back of the list.

List to get the element from
Index as a number

Return the element or -1 if the index is out of bounds.

Execution

This repo includes a python script to run code written in Lil Dolbaeb.

To use it, clone the repository, cd into it and run:

python execute.py <code filename> [...args]

gxlg / lil-dolbaeb Goto Github PK

lil-dolbaeb's Introduction