Fg

This is still a work in progress. It may be changed in the future.

Fg

Paradigm(s)	Unknown
Designed by	User:NutronStar45
Appeared in	2023
Computational class	Unknown
Reference implementation	Unimplemented
File extension(s)	Unknown

Fg is a programming language created by User:NutronStar45.

Values

A value in Fg has a type and can have one or more supertypes.

Types

Name	Description	Example
int	32-bit signed integer	2147483647
long	64-bit signed integer	2147483648L
float	Single-precision floating point number	6.283185
double	Double-precision floating point number	6.28318530717959d
bool	Boolean value	true
str	String of characters encoded in utf-8	"Hello World\n"
void	Default return value of subroutines and functions	(void)
list	Ordered collection of values	[1, 2, 3]
dict	Ordered collection of key-value pairs	["R" 0, "G" 1, "B" 1]
subr	Subroutine (set of defined procedures without parameters with return value)	{ (out "Hello World\n") }
func	Function (set of defined procedures with parameters with return value)	(new func "args" { (out (str args)) })
olfunc	Overloaded function (a function with multiple implementations)	(new olfunc func1 func2)
type	Data type	(new type)

• int

int objects are 32-bit signed integers. They can be constructed by writing an integer in decimal, e.g. 1234

• long

long objects are 64-bit signed integers. They can be constructed by writing an integer in decimal and appending an L after it, e.g. 2147483648L

• float

float objects are 32-bit floating point numbers (8-bit exponent and 23-bit mantissa). They can be constructed by writing a number with one decimal (.), e.g. 1234.

• double

double objects are 64-bit floating point numbers (11-bit exponent and 52-bit mantissa). They can be constructed by writing a number with one decimal (.) and appending an d after it, e.g. 1234.d

• bool

bool objects are boolean values that can either be true or false. They can be constructed by writing true or false.

• str

str objects are strings of characters encoded in utf-8. They can be constructed by surrounding characters by single (') or double (") quotation marks, e.g. "Hello World\n". For including quotation marks and special characters in strings, see #Escape characters.

• void

void is the type of the default return value of subroutines and functions, and only has one value: (void)

• list

list objects are ordered collections of values that can be of different types. They can be constructed by surrounding values separated by commas (,) with brackets ([]), e.g. [1, 2, 3]

• dict

dict objects are ordered collections of key-value pairs, and each key and value can be of different types. They can be constructed by surrounding key-value pairs (with keys and values separated by whitespace characters) separated by commas (,) with brackets ([]), e.g. ["R" 0, "G" 1, "B" 1]

• subr

subr objects are sets of defined procedures that don't have parameters and may return a value. They can be constructed by surrounding the procedures separated by whitespace characters with braces ({}), e.g. { (out "Hello World\n") (out "This is a subroutine") }

• func

func objects are sets of defined procedures that have parameters and may return a value. They can be constructed by creating a new instance of func with the name of the variable that the list of parameters will be stored at as the first argument and the subroutine as the secon, e.g. (new func "args" { (out (str args)) })

• olfunc
• type

Escape characters

Escape characters are a way to include quotation marks and special characters in strings, and they start with backslashes (\).

Escape characters in Fg include:

Built-in functions

Arithmetic

• add
• sub
• mul
• div
• exp

Comparisons

• eq
• ne
• gt
• lt
• ge
• le

Logic

• and
• or
• not
• xor

Variables

• var
• set

Control flow

• if
• while
• dowhile
• repeat
• iter
• ret
• break
• continue

IO

• in
• out

Types

• int
• long
• float
• double
• bool
• str
• list
• dict
• subr
• func
• olfunc
• type

OOP

• new

Others

• join
• range
• ref
• prop
• propref

Examples

Hello World

(out "Hello World\n")

Cat

(out (in))

Truth-machine

({
  (var "input" str)
  (set (ref "input") (in))
  (if (eq input "0") { (out "0") } (eq input "1") {
    (repeat { (out "1\n") })
  })
})

Fibonacci function

(new func "n" {
  (var "a" int)
  (var "b" int)
  (set (ref "a") 0)
  (set (ref "b") 1)
  (repeat n {
    (set (ref "b") (add a b))
    (set (ref "a") (sub b a))
  })
  (ret a)
})

99 bottles of beer

({
  (var "count" subr)
  (set (ref "count") {
    (if (eq bottles 0) { (out "No") } { (out (str bottles)) })
    (out (str bottles))
    (out " ")
    (if (eq bottles 1) { (out "bottle") } { (out "bottles") })
  })
  (var "bottles" int)
  (set (ref "bottles") 99)
  (while (ne bottles 0) {
    (count)
    (out " of beer on the wall,\n")
    (count)
    (out " of beer.\nTake one down, pass it around,\n")
    (set (ref "bottles") (sub bottles 1))
    (count)
    (out " of beer on the wall.")
  })
})