FABRIS PROGRAMMING LANGUAGE

Introduction

Fabris is a stack-oriented, concatenative language designed to be simple, friendly and efficient.

Fabris is inspired by Forth, Python, Joy, DSSP, Factor, COBOL and Unix.

Current Fabris version is unstable and is intended only for experimental use.

The name comes from first leters of main components of Fabris VM: (F)ixed point base, (A)uxiliary pointers, (B)ase pointer, (R)eturn stack, (I)nstruction pointer, (S)tack.

Similarity with the name of Italian fencing master Salvator Fabris is not a coincidence.

Basic Syntax

Basic expressions:

"the answer is " print 40 2 add dot

Line comment:

"hello world" print -- the rest of line is ignored
-- this line is also ignored

Stream comment:

4 10 mul (this is a comment) 1 1 add add ( this also )

Conditional statement:

if 10 equal then "equals ten" print end

Conditional statement with alternative:

if 10 or-more then "ten or more" else "nine or less" end

Conditional statement with multiple branches:

10 or-more then "ten or more"   else
 8 or-less then "eight or less" else
            "exactly nine"  end

Counted loop:

3 times
    "Hastur! " print
loop

Universal loop:

do
    scan-for-enemies
    if enemy then
    break end
    patrol-area
loop
exterminate exterminate exterminate

New function definition:

def square dup mul ret

New function definition with named parameters:

def energy in h m v out 1 (e)
    m v v mul mul 2 div -- kinetic energy
    h m g mul mul -- potential energy
    add (e) ret

Testing:

test 40 2 add 42 ok
test 10 dup inc 11 ok 10 ok

Lambda expressions:

[ " world" print ] [ "hello" print ] call call -- prints "hello world"

Recurrency:

def print-stack
    if depth then dot drop print-stack end ret

List reduction:

[ 1 3 5 7 9 ] list [ add ] fold -- sum all elements

Include module:

use string
do each-word
print
loop

Top-down programming:

def c b ret
def b a ret
def a 42 ret

c dot -- prints 42

Fixed point arithmetics:

1000 tof
3.14159    2  mul fdot -- prints 6.282
3.14159  2.0 fmul fdot -- prints 6.282
   3141    2  mul fdot -- prints 6.282
   3141 2000 fmul fdot -- prints 6.282

Functions

Stack Manipulation

name effect comments core

swap (ab--ba) swap the two top stack items yes

dup (a--aa) duplicate the top stack item yes

drop (a--) discard the top item yes

depth (--n) push number of items on stack yes

tor (a--)(=a) move the top item to the return stack yes

r (--x)(a=) move the top item of return stack to stack yes

tof (a--) move the top item to the fixed point base yes

name	effect	comments	core
swap	(ab--ba)	swap the two top stack items	yes
dup	(a--aa)	duplicate the top stack item	yes
drop	(a--)	discard the top item	yes
depth	(--n)	push number of items on stack	yes
tor	(a--)(=a)	move the top item to the return stack	yes
r	(--x)(a=)	move the top item of return stack to stack	yes
tof	(a--)	move the top item to the fixed point base	yes

Basic Arithmetic

name effect comments core

add sub mul div mod inc dec abs

(ab--x) (ab--x) (ab--x) (ab--x) (ab--x) (a--x) (a--x) (a--x)

add two top items (a+b) subtract top item from second item (a-b) multiply two top items (a*b) divide second item by top item (a/b) reminder of dividing second item by top item (a%b) increment the top item (a+1) decrement the top item (a-1) return absolute value (abs(a))

yes

neg (a--x) change the sign (-a) yes

fmul (ab--x) fixed point - multiply two top items (a*b) opt.

fdiv (ab--x) fixed point - divide of second item by top item (a/b) opt.

name	effect	comments	core
add sub mul div mod inc dec abs	(ab--x) (ab--x) (ab--x) (ab--x) (ab--x) (a--x) (a--x) (a--x)	add two top items (a+b) subtract top item from second item (a-b) multiply two top items (a*b) divide second item by top item (a/b) reminder of dividing second item by top item (a%b) increment the top item (a+1) decrement the top item (a-1) return absolute value (abs(a))	yes
neg	(a--x)	change the sign (-a)	yes
fmul	(ab--x)	fixed point - multiply two top items (a*b)	opt.
fdiv	(ab--x)	fixed point - divide of second item by top item (a/b)	opt.

Comparators

name effect comments core

zero (a--ax) check if a == 0 yes

negative positive less or-less more or-more equal within

(a--ax) (a--ax) (ab--ax) (ab--ax) (ab--ax) (ab--ax) (ab--ax) (nab--nx)

check if a < 0 check if a > 0 check if a < b check if a <= b check if a > b check if a >= b check if a == b check if a <= n <= b

yes

name	effect	comments	core
zero	(a--ax)	check if a == 0	yes
negative positive less or-less more or-more equal within	(a--ax) (a--ax) (ab--ax) (ab--ax) (ab--ax) (ab--ax) (ab--ax) (nab--nx)	check if a < 0 check if a > 0 check if a < b check if a <= b check if a > b check if a >= b check if a == b check if a <= n <= b	yes

Logic

name effect comments core

and (ab--x) and two top items (a&b) yes

or (ab--x) or two top items (a|b) yes

xor (ab--x) xor two top items (a^b) yes

not (a--x) logical negation (!a) yes

name	effect	comments	core
and	(ab--x)	and two top items (a&b)	yes
or	(ab--x)	or two top items (a\|b)	yes
xor	(ab--x)	xor two top items (a^b)	yes
not	(a--x)	logical negation (!a)	yes

Input/Output

name effect comments core

emit (c--) write single character to standard output yes

take (--c)

read single character from standard input

opt.

untake print

(c--) (an--)

unread single character from standard input

prints n characters at address a

opt.

argc (--x) returns number of program arguments opt.

argv dot fdot udot xdot write

(a--xn) (a--a) (a--a) (a--a) (a--a) (anf--)

returns address and length of argument number a prints top item as number followed by space prints top item as fixed point number followed by space prints top item as unsigned number followed by space prints top item as hexadecimal number followed by a space write n characters at address a to file with descriptor f

opt.

name	effect	comments	core
emit	(c--)	write single character to standard output	yes
take	(--c)	read single character from standard input	opt.
untake print	(c--) (an--)	unread single character from standard input prints n characters at address a	opt.
argc	(--x)	returns number of program arguments	opt.
argv dot fdot udot xdot write	(a--xn) (a--a) (a--a) (a--a) (a--a) (anf--)	returns address and length of argument number a prints top item as number followed by space prints top item as fixed point number followed by space prints top item as unsigned number followed by space prints top item as hexadecimal number followed by a space write n characters at address a to file with descriptor f	opt.

Control/Flow

name effect comments core

def X (--) define new word X yes

ret (--) return from definition yes

macro X (--) define new macro X opt.

mend (--) end macro definition opt.

then (x--) execute following code if x is not zero yes

else (--) branch for the then word (optional) yes

end (--) finish then/else sequence yes

do (=x) start of unconditioned loop yes

break (x=) break out of the current loop yes

loop (--) repeat loop yes

times (x--)(=i) start of counted loop yes

"X" (--an) start/end of a string, places addres and length on the stack yes

[ (--) start of anonymous code block yes

] (--r) end of anonymous code block, put reference to it on the stack yes

_ (x--) capture stack item into code block, right to left yes

call (r--) call code block referenced by r yes

yield (--r) return and push reference to next instruction yes

'X' (--c) start/end of a char yes

X (--x) place integer X in the stack yes

use X (--) use module X yes

dyn X (--) declare word X as dynamic, that can change at the runtime yes

ref X (--r) put reference to word X on the stack yes

as X (r--) redefine dynamic word X as code reference r yes

in X... (--) define names of input parameters, set input register yes

out X (--) define number of output parameters yes

name	effect	comments	core
def X	(--)	define new word X	yes
ret	(--)	return from definition	yes
macro X	(--)	define new macro X	opt.
mend	(--)	end macro definition	opt.
then	(x--)	execute following code if x is not zero	yes
else	(--)	branch for the then word (optional)	yes
end	(--)	finish then/else sequence	yes
do	(=x)	start of unconditioned loop	yes
break	(x=)	break out of the current loop	yes
loop	(--)	repeat loop	yes
times	(x--)(=i)	start of counted loop	yes
"X"	(--an)	start/end of a string, places addres and length on the stack	yes
[	(--)	start of anonymous code block	yes
]	(--r)	end of anonymous code block, put reference to it on the stack	yes
_	(x--)	capture stack item into code block, right to left	yes
call	(r--)	call code block referenced by r	yes
yield	(--r)	return and push reference to next instruction	yes
'X'	(--c)	start/end of a char	yes
X	(--x)	place integer X in the stack	yes
use X	(--)	use module X	yes
dyn X	(--)	declare word X as dynamic, that can change at the runtime	yes
ref X	(--r)	put reference to word X on the stack	yes
as X	(r--)	redefine dynamic word X as code reference r	yes
in X...	(--)	define names of input parameters, set input register	yes
out X	(--)	define number of output parameters	yes

Other

name effect comments core

nop (--) do nothig

clock (--x) returns number of microseconds since the program was launched opt.

halt (--) stops program execution yes

peek (a--c) get character (unsigned) from address a opt.

poke ok trace sprint

(ca--) (ab--) (--) (--)

set character at addres a to c halt and print error if two top items are not equal prints information about VM state - stack, ip, ... prints stack

opt.

name	effect	comments	core
nop	(--)	do nothig
clock	(--x)	returns number of microseconds since the program was launched	opt.
halt	(--)	stops program execution	yes
peek	(a--c)	get character (unsigned) from address a	opt.
poke ok trace sprint	(ca--) (ab--) (--) (--)	set character at addres a to c halt and print error if two top items are not equal prints information about VM state - stack, ip, ... prints stack	opt.

More Logic

name effect comments core

shl shr ushr inv

(ab--x) (ab--x) (ab--x) (a--x)

shift a left by b bits (a<<b) shift a right by b bits (a>>b) shift unsigned a right by b bits (a>>b) invert all bits (~a)

name	effect	comments	core
shl shr ushr inv	(ab--x) (ab--x) (ab--x) (a--x)	shift a left by b bits (a<<b) shift a right by b bits (a>>b) shift unsigned a right by b bits (a>>b) invert all bits (~a)

More Stack Manipulation

name effect comments core

over nip tuck rot unrot yank mark count cut chars bytes ndrop dup2 swap2 drop2 pick reverse reverse2

(ab--aba) (ab--b) (ab--bab) (abc--bca) (abc--cab) (--a)(ab=b) (--)(=n) (--x)(n=) (?--)(n=) (n--x) (n--x) (?n--) (ab--abab) (abxy--xyab) (ab--) (n--x) (?n--?n) (?n--?n)

push the second item on top discard the second item insert copy of top item before second item rotate the third item to the top unrotate the top to the third item remove second item from return stack and place it on stack mark stack location (push stack depth to return stack) push number of items after the mark, unmark stack drop items after marked stack location calculate number of items for storing n characters calculate number of items for storing n bytes discard n top items (not counting n) duplicate top pair swap two pairs drop pair pick nth stack item from top (not counting n) reverse order of n top stack items reverse order of n top stack pairs

name	effect	comments	core
over nip tuck rot unrot yank mark count cut chars bytes ndrop dup2 swap2 drop2 pick reverse reverse2	(ab--aba) (ab--b) (ab--bab) (abc--bca) (abc--cab) (--a)(ab=b) (--)(=n) (--x)(n=) (?--)(n=) (n--x) (n--x) (?n--) (ab--abab) (abxy--xyab) (ab--) (n--x) (?n--?n) (?n--?n)	push the second item on top discard the second item insert copy of top item before second item rotate the third item to the top unrotate the top to the third item remove second item from return stack and place it on stack mark stack location (push stack depth to return stack) push number of items after the mark, unmark stack drop items after marked stack location calculate number of items for storing n characters calculate number of items for storing n bytes discard n top items (not counting n) duplicate top pair swap two pairs drop pair pick nth stack item from top (not counting n) reverse order of n top stack items reverse order of n top stack pairs

String Manipulation

name effect comments core

hash split strip lstrip rstrip substr index

(an--x) (an--rxfy) (an--bx) (an--bx) (an--bx) (ankc--anbc) (anbm--anx)

return hash value for given string (x65599 algorithm) return first word from a string and the rest of the string return string without leading and trailing whitespaces return string without leading whitespaces return string without trailing whitespaces return substring of c characters starting at b return index of bm string within an string, or -1

char upper lower

(ani--anx) (an--an) (an--an)

return character at index i in given string

destructive change to lowercase destructive change to uppercase

yes?

name	effect	comments	core
hash split strip lstrip rstrip substr index	(an--x) (an--rxfy) (an--bx) (an--bx) (an--bx) (ankc--anbc) (anbm--anx)	return hash value for given string (x65599 algorithm) return first word from a string and the rest of the string return string without leading and trailing whitespaces return string without leading whitespaces return string without trailing whitespaces return substring of c characters starting at b return index of bm string within an string, or -1
char upper lower	(ani--anx) (an--an) (an--an)	return character at index i in given string destructive change to lowercase destructive change to uppercase	yes?

String Comparators

name effect comments

begins (anbm--anx) return true if an string begins with bm string

ends (anbm--anx) return true if an string ends with bm string

contains (anbm--anx)

return true if an string contains bm string

arein (anbm--anx)

return true if an string contains any character from bm string

haschar (anc--anx)

return true if an string contains character c

name	effect	comments
begins	(anbm--anx)	return true if an string begins with bm string
ends	(anbm--anx)	return true if an string ends with bm string
contains	(anbm--anx)	return true if an string contains bm string
arein	(anbm--anx)	return true if an string contains any character from bm string
haschar	(anc--anx)	return true if an string contains character c

More Arithmetic

name effect comments

min (ab--x) return lower value

max (ab--x) return greater value

limit (xab--y) limit value of x (aka clamp), if x<a then a, if x>b then b

divmul (abc--x)

... (a/b*c)

muldiv (abc--x)

... (a*b/c)

muldivmod (abc--xr)

... (a*b/c, a*b%c)

divmod (ab--xr)

... (a/b, a%b)

name	effect	comments
min	(ab--x)	return lower value
max	(ab--x)	return greater value
limit	(xab--y)	limit value of x (aka clamp), if x<a then a, if x>b then b
divmul	(abc--x)	... (a/b*c)
muldiv	(abc--x)	... (a*b/c)
muldivmod	(abc--xr)	... (ab/c, ab%c)
divmod	(ab--xr)	... (a/b, a%b)

Performance

Different dispatching techniques results in different efficiency depending on the CPU architecture¹.

Fabris offers multiple dispatching strategies in the single VM.

benchmark N goto switch call direct repl.sw c.call c.inl python ENV VM cfg

nested-loops 16

508

862

990

391

518

489

464

11671

E.1

C.0

nested-loops 16

398

882

934

287

546

400

369

7142

E.1

C.1

fibonacci 32

867

1043

1183

665

904

520

485

6037

E.1

C.0

fibonacci 32

620

1017

1001

501

787

506

401

4524

E.1

C.2

benchmark	N	goto	switch	call	direct	repl.sw	c.call	c.inl	python	ENV	VM cfg
nested-loops	16	508	862	990	391	518	489	464	11671	E.1	C.0
nested-loops	16	398	882	934	287	546	400	369	7142	E.1	C.1
fibonacci	32	867	1043	1183	665	904	520	485	6037	E.1	C.0
fibonacci	32	620	1017	1001	501	787	506	401	4524	E.1	C.2

Programs are based on Benchmark Tests from http://dada.perl.it/shootout/.

Times are given in milliseconds for best of 5 runs. More benchmarks and results coming soon.

Environment:

E.1 - Intel Atom N570 1.66 @ 1.0 GHz, gcc 4.8.4, -O3 -fomit-frame-pointer

VM config:

C.0 - Default Fabris config. Python 3.5
C.1 - Fabris registers: sp on ESI, ip on EDI. Python 2.7
C.2 - Fabris registers: sp on ESI, ip on EDI, rp on EBX. Python 2.7

Friendly Language

http://www.complang.tuwien.ac.at/forth/threading/↩

mobarski / fabris Goto Github PK

fabris's Introduction

FABRIS PROGRAMMING LANGUAGE

Introduction

Basic Syntax

Functions

Stack Manipulation

Basic Arithmetic

Comparators

Logic

Input/Output

Control/Flow

Other

More Logic

More Stack Manipulation

String Manipulation

String Comparators

More Arithmetic

Performance

Simplicity

Friendly Language

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