Laktano

Laktano is an alternative version of Python in PsiLine universe, which is designed and developed by Mike Traussicha.

In OTL universe, it is designed by PSTF.

Overview

Laktano is Turing-complete, High-level and easy language, it supports on a lot of operating systems. Currently, popular OS's in PsiLine are Fraug, Verfan, Windowzie, Brandig, SL-droid.

Basic Syntax

Comment

In Laktano, comment starts with flipped apostrophe.

` This is single line comment.
`` This is a comment block. ``

Procedural framework

Procedural framework in Laktano is nothing, and the main function is <main>.

I/O

In Laktano, I/O can be done like this:

Output

print(*args, filename = 'CON', end = '\n')

This output function accepts an unlimited number of values, with filename as the output medium and end as the terminator. By default, filename is directed to standard output and ends with a line break.

Input

In Laktano, there are two types of input, one is evaluation input and the other is normal input.

Eval-input

Evaluation input uses this:

input(__prompt)

It returns the value of the entered expression. If the entered expression is incorrect, it will simply return an error. This function was deprecated after Laktano 2.5.

Std-inpnut

Normal input uses this:

read(__prompt)

It returns a string no matter what is entered. Of the two input functions, __prompt is used to prompt the user for input. The value of the __prompt is output before the user inputs. This function was merged with input() after Laktano 2.5.

Data structure

Identifier

Laktano's identifier works like Python in OTL universe(the universe which we live in). That is, every identifier valid in Python may also valid in Laktano.

Variable

To define a variable, you need to specify its type or value, or both. You can also omit them all, but var mustn't be omitted. when you omit type and value, it means create a NULL variable.

var (variable_type) variable_name (= variable_value)

Leave variable_value blank means to delete it.

Type

Currently, we have these types:

• Numbers, such as 3, 7, 3.14, -2, 114514, 1e20, 3.683E-34, 3.130582375184619046479671967486, etc. Initial value is 0 for int, 0/1 for frac, and 0.0 for float.
• Strings, such as 'Hello' (or "Hello"). Strings can be enclosed in double quotes or single quotes, just like work in Python. Initial value is "".
• Booleans. It can only be True, or False. Initial value is False.
• Arrays. This is the most important data type in StormLang, it can express a list or a dictionary, such as [1, 2, 3], or [key = value]. Initial value is [].
• Tuples. It is just a "unchangable array", such as (5, 2), (4, 8, 3, 8, 9), but (1, ) instead of (1). Initial value is (,).
• Functions. They're 1st-class citizens, which can be passed and returned as arguments.
• Empty types. They has only a value, None. They converts to 0, but they can used to be true.
• User-defined types. They're defined by "data" command.
• Undefined behaviour. This often occurs when you trying to do something incorrect, such as 5/0.
• Documents. They have same type of string, but they quoted by three double-quotes or single-quotes. initial value is """""".

	Integer	Fraction/Float	Boolean	String	Array	Nil	Undefined
Integer		floor(x)	x ? 1 : 0	parseInt(x) or 0	length(x)	0	0
Fraction/Float	x/1		x ? 1.0 : 0.0	parseFloat(x) or 0.0	length(x) / 1	0.0	0.0
Boolean	x != 0	x != 0.0		x != ""	x != []	true	false
String	toString(x)	toString(x)	x ? "true" : "false"		"[" + ", ".join(x) + "]"	""	99 bottles of beer on the wall
Array	[x]	[x]	[x]	[x]		[]	[Undefined]

Forced and persistent type conversions

To cast the type of one expression to another, simply enclose parentheses around the expression and add the corresponding type. To permanently convert the type of one variable to another, you need to assign the corresponding type directly to the variable. For example, n = int means converting n to an integer.

Conditional Jump

Conditional jump often show as if-elif-else statement.

There must be an if statement block in the conditional judgment statement. A conditional statement can have a large number of elif blocks or no of it, but it can have and at most one else block.

if condition:
    code
elif condition2:
    code2
else
    code3
endif

Trinocular operator

Conditional judgement also supports trinocular operator.

B?A:C

It means, if B is true, then return A, otherwise return C.

Loops

Currently, Laktano supports three kinds of loop.

Iterative loops

for variable in sequence_or_iteration_objects
    code
endloop

Now that we're talking about this iteration loop, we have to mention how to generate a number sequence.

Number sequence

range(start, stop, step, haveend = false, havestart = true)

This function generates an interval with start point, end point, step-length, and didn't include end point.

At the same time, the actual arguments are passed in according to the order of the parameters, so it is possible to include only one true to generate an open interval, or two false to generate a closed interval.

Conditional loops

Check-first

while condition:
    code
endloop

Do-first

do
    code
while condition
endloop

Functions

Functions are the most important program structure, and they can make your code much shorter. Here's the definition of a function:

function function_name(*args, **kwargs):
    code
    return return_values
endfunc

Since the function is mentioned, let's talk about the lambda expression by the way.

Lambda expression

lambda(*args: expression)(*your_args)

Such as:

lambda(a, b: a + b)(int(read()), int(read()))

This should be works like an A+B Problem.

Object oriented

Definition of a class

class YourClassName:
    attributes
    
    function __init__(self):
        my.attr = attr
    endfunc
    
    more_functions
endclass

Interihance and Override

class Rect:
    var a = None
    var b = None
    
    function __init__(self):
        my.a = a
        my.b = b
    endfunc
    
    function circumference(self):
        return 2 * (my.a + my.b)
    endfunc
    
    function area(self):
        return my.a * my.b
    endfunc
endclass

` Squares are special rectangular shapes.
class Square(Rect):
    function __init__(self):
        super(Rect.a)
        my.b = 
    endfunc
    
    override function area(self):
        return a ^ 2 
        ` One ^ sign refers to a power operation, and two is a bit XOR. Logical operators and bitwise operators are reversed.
    endfunc
    
    override function circumference(self):
        return 4 * a
    endfunc
endclass

Examples

Greatest common divisor with no STL

function gcd_euclid(x, y):
    var int r = x % y
    while r != 0:
        x = y
        y = r
        r = x % y
    endloop
    return y
endfunc

function gcd_jiuzhang(x, y):
    var int d = x - y
    while y != d:
        x = y
        y = d
        d - x - y
    endloop
    return d
endfunc

var int a = int(read())
var int b = int(read())
print(gcd_euclid(a, b))
print(gcd_jiuzhang(a, b))

Fibonacci sequence

function fibonacci(x):
    if x < 0:
        return undefined
    elif x == 0:
        return 0
    else:
        return (x + fibonacci(x - 1))
    endif
endfunc

var int a = int(read())
print(fibonacci(a))