blang

**EXTREMELY IMPORTANT! THIS LANGUAGE IS A WORK IN PROGRESS! ANYTHING CAN CHANGE AT ANY MOMENT WITHOUT ANY NOTICE! USE THIS LANGUAGE AT YOUR OWN RISK!

Blang is a Concatenative Stack-Oriented Programming Language for Computers

(If you never heard about this kind of languages before check out https://concatenative.org/)

Development Milestones

• Compiled to a custom instruction set (BVM bytcode)
• Conditional/selection statements
• Loops
• Turing-complete
• Crossplatform
• Strings support
• Functions
• Self hosted
• Statically typed
• Optimized
• Implement a vm as a custom cpu for fpga

Examples

Hello, World:

0 "HelloWorld" printstring

endscript . 

Simple program that prints all upper letters:

65 ? a
while
	a charprint 
	89 < if
		breakloop
	end 
1 a + ? a
endloop
endscript .

Quick Start

Compile project :

gcc main.c OR make all

Compile to bytcode:

 main.out -c <path to program> <path to save>

Run the bytcode:

 main.out -r <path to bytcode> 

Usage:  Compile -c <path to program> <path to save>
        Run -r <path to saved>

Language Reference

This is what the language supports so far. Since the language is a work in progress everything in this section is the subject to change.

Literals

Integer

Currently an integer is a sequence of decimal digits. When an integer is encountered it is pushed onto the data stack for processing by the relevant operations.

Example:

10 20 +

The code above pushes 10 and 20 onto the data stack and sums them up with + operation.

String

TBD

Character

Currently a character is a only used as a var on heap. For printing of a char ther is a function called charprint. Also for working of a strings ther is a function called printstring. You are obliged to provide end token that is 0. Example:

  35 ? taraba 
  32 ? space 
  10 ? newLine

Intrinsics (Built-in Words)

Stack Manipulation

Name	Signature	Description
dup	a -- a a	duplicate an element on top of the stack.
swap	a b -- b a	swap 2 elements on the top of the stack. TBD
drop	a b -- a	drops the top element of the stack.
print	a b -- a	print the element on top of the stack in a free form to stdout and remove it from the stack.
over	a b -- a b a	copy the element below the top of the stack.
rot	a b c -- b c a	rotate the top three stack elements.

Comparison

Name	Signature	Description
=	[a: int] [b: int] -- [a == b : int]	checks if two elements on top of the stack are equal.
=!	[a: int] [b: int] -- [a != b : int]	checks if two elements on top of the stack are not equal.
>	[a: int] [b: int] -- [a > b : int]	applies the greater comparison on top two elements.
<	[a: int] [b: int] -- [a < b : int]	applies the less comparison on top two elements.
<!	[a: int] [b: int] -- [a >= b : int]	applies the greater or equal comparison on top two elements.
>!	[a: int] [b: int] -- [a <= b : int]	applies the less or equal comparison on top two elements.

Arithmetic

Name	Signature	Description
+	[a: int] [b: int] -- [a + b: int]	sums up two elements on the top of the stack.
-	[a: int] [b: int] -- [a - b: int]	subtracts two elements on the top of the stack
*	[a: int] [b: int] -- [a * b: int]	multiples two elements on top of the stack
/	[a: int] [b: int] -- [a / b: int]	divide two elements on top of the stack
%	[a: int] [b: int] -- [a % b: int]	mod two elements on top of the stack

Bitwise

Name	Signature	Description
shr	[a: int] [b: int] -- [a >> b: int]	right unsigned bit shift.
shl	[a: int] [b: int] -- [a << b: int]	light bit shift.
or	[a: int] [b: int] -- [a | b: int]	bit or.
and	[a: int] [b: int] -- [a & b: int]	bit and.
not	[a: int] -- [~a: int]	bit not.

Memory

Name	Signature	Description
?	<stack> let <name>	Store a value from at the var addres. If var is not declared create the var on <stacksize - numofvars - 1>.
arr	arr <name> <size>	Create a array on first free addres on stacksize - numofvars - 1.
&	ptr <name>	Push a mem addres of a var on top of the stack.
@	<stack> ptrval	Push a value from mem addres from top of the stack on top of the stack.
??	<stack> <stack> ptrval	Store a value from to mem addres on sp

System

• syscall<n> - TBD
• c functions - TBD

Control Flow

if-condition

If only if

<Comparison> if
  <body> 
<end>

If/else if

<Comparison> dup if
  <body> 
<end>
else
  <body>
end

Example:

0 10 
= dup
if
	20 print
	30 40 = dup
	if 
		30 print
	end
	else 
		50 print
	end
end
else
	30 print
end
40 print
endscript .
end

while-loop

Infinite loop:

while 
   <body>
endloop

Condition loop use breakloop to exit a loop:

while
  <body>
  <Comparison> if
    <body>
    breakloop 
  <end>
endloop

Procedures and functions

Keyword word declare a procedure or function. We coude pass values thru stack so for example we push them on stack and then do with a stack. Also we coude provide a value thru heap.

word printString 
	while
		dup @ charprint 
		0 = if
			breakloop
		end
		1 + 
	endloop
	drop
endword


& H printString

Procedure Pointers

TBD

Constants

Const is declared like this:

word pi 3.1415 endword

Memory

There is a heap witch is build on top of the stack.
Vars are global for entire duration of a program.

Type Checking

There are 4 types: int64 , float64 , uint64, ch (basicly uint64 just used in strings). Type is inferd for math operation based on a last element on a stack. For example if we have 10 10.2 on stack and we do + + operation will use float type be send as a operand.