PAL
PAL is an esolang created by islptng. It is designed to have no flow control.
Programs consist of a single expression containing nested function calls, lambdas and literals (numbers and lists), written using Polish (prefix) notation. Each function has a predefined number of arguments, making the notation unambiguous.
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Data types
There are 3 data types.
- Number, which stores a fraction.
- List, which stores a list of objects.
- Lambda, which is a monadic lambda function
Syntax
In this esolang, a program is a single expression. They're written in Polish(Prefix) notation.
Like @ and XENBLN, expressions are made of trees of function calls. Each character represents a function that takes a predefined amount of arguments, which follow directly after it in the code. For example, if command A takes 1 argument, B takes 2, C takes 3, and D and E both take none, then this code
CBADCDBEDEDAE
would be written in many languages like
C(B(A(D()),C(D(),B(E(),D()),E()))),D(),A(E()))
There are exceptions. To define a list, you use []; To define a lambda, you use {}.
There are some special cases in the console.
A line that begins with ] prints the text after it.
A line that begins with } defines macros.
To separate 2 integers, use a space. Otherwise, you won't need any separators.
True is 1, and False is -1 (unlike most languages, which is 0; In this language, however, 0 is truthy).
Implementation
Examples
Hello World
]Hello, world!
XKCD Random Number and Quine
4
Since the whole program is an expression, a single number evaluates to itself, and finally it's printed.
A+B problem
+a b
Replace a and b with your integer since this language has no input!
Factorial
f{i1{*#x0#x1}r1+1x1} 10
Output: 3628800 (10! = 3628800)
FizzBuzz
~{?=0%x5?=0%x3-41228022-8022?=0%x3-4122x}r1 101 1
Since this language is not able to print (only evaluation), the result will be a list.
Like the Mathematics solution, Fizz/Buzz/FizzBuzz are replaced with -4122/-8022/-41228022.
Judge a number is prime or not
f{->x_~{r*x2*xxx}r2+1x1} 87
Output: -1 (87=3*29 not a prime)
f{->x_~{r*x2*xxx}r2+1x1} 97
Output: 1 (97 is a prime)