SLet/algo

This will be the tutorial of SLet.

Part 1: Basics

Data structures

Boolean

Nothing to say. It's True and False, just like most languages. Non-zero numbers are True, and zero is False.

Number

Simply enough, stores a number(we use fraction instead of decimal). Dividing a thing by 0 results to infinity and NaN, depending on the number.

Pair

Stores 2 values, one "former", one "latter".

Set

The major data type. It is always sorted from small to large.(Boolean<Number<Pair<Set<Lambda)

Lambda

You can define functions using this.

Syntax

This language uses Polish(Prefix) notation, which means you first write the command, then the arguments.
Arguments are directly written without separators most of the time, but you must insert a space between variable names or/and numbers.
String literals do not exist in this language. Comments can be written between parentheses(can be nested).

Commands

Click the "[Expand]" on the right to show a list of commands.

# var val(let) Assign a value to a variable

Flow Control

~ set var op
For every object in the set, store it in variable named "var" If op is a lambda: execute op.
If op is an expression: The return value of this command will contain this object iff op returns True.

[ expr op
While expr returns True, executes op.

\ ...code... !
Makes a lambda.

@ lambda
Executes the lambda.

Input/Output

; reads a character from stdin and returns its ASCII value.
, reads a fraction from stdin (Must end with a newline) and returns its value.
: num prints a character to stdout.
. obj prints an object to stdout.
` num digits prints a fraction as decimal to the given digit after point.

Data structures and calculations

' former latter
Makes a pair.

| ...objects... !
Makes a set. Also does union between sets.

- obj
If obj is a number, negate, and return the result.
If obj is a boolean, it is "not" operator.
If obj is a set, it returns a random object in it.
If obj is a pair, it returns randint(former, latter).

$ obj
If obj is a number, return its reciprocal.
If obj is a set, it returns its size.
If obj is a pair, it returns (latter, former).

< obj
If obj is a pair or a set, returns its first value.
If obj is a number, return its numerator.

> obj
If obj is a pair or a set, returns its last value.
If obj is a number, return its denominator.

^ obj
Packs obj into a set i.e. returns {obj}

= a b
If a and b are both sets, it returns True if a is a subset of b.
If neither of a and b is sets, it returns True if a equals to b.
If b is a set but a isn't, it returns True if a is in b.

+ a b
If a and b are both numbers, return their sum.
If a and b are both boolean, it is the "or" operator.

* a b
If a and b are both numbers, return their sum.
If a and b are both boolean, it is the "and" operator.
If a and b are both sets, return their intersect.

/ a b
Floor division. Returns int(a/b).

% a b
Modulus. Returns a mod b.

] from to step
Range. Returns a set consist of numbers.