abyssix

A procedural structured programming language.

Examples

Hello world

func main {
  params 0;
  alloc 0;

  putc 72;
  putc 101;
  putc 108;
  putc 108;
  putc 111;
  putc 32;
  putc 119;
  putc 111;
  putc 114;
  putc 108;
  putc 100;
  putc 10;
}

FizzBuzz

func main {
  params 0;
  alloc 1;

  set.0 = 1;
  while  get.0  int.<=  100: {
    if  get.0  int.%  15  int.==  0: {
      putc 70; putc 105; putc 122; putc 122; putc 66; putc 117; putc 122; putc 122;
    } else if  get.0  int.%  3  int.==  0: {
      putc 70; putc 105; putc 122; putc 122;
    } else if  get.0  int.%  5  int.==  0: {
      putc 66; putc 117; putc 122; putc 122;
    } else {
      printInt(get.0);
    }
    putc 10;
    set.0  =  1  int.+  get.0;
  }
}

func printInt {
  params 1;

  alloc 24;
  // 0: target to print
  // 1-21: char buffer
  // 22: buffer length
  // 23: iteration variable

  set.0  =  param.0;
  if  get.0  int.==  0: {
    putc 48; // print '0'
    return 0;
  } else if  get.0  int.<  0: {
    set.0  =  int.-  get.0;
    putc 45; // print '-'
  } else {
    // do nothing
  }
  while  get.0  int.>  0: {
    set[1  int.+  get.22]  =  get.0  int.%  10;
    set.0  =  get.0  int./  10;
    set.22  =  get.22  int.+  1;
  }
  set.23  =  get.22  int.-  1;
  while  get.23  int.>=  0: {
    putc(48  int.+  get[1  int.+  get.23]);
    set.23  =  get.23  int.-  1;
  }
}

Syntaxes

Function definition

func functionName {
  params 0;
  alloc 0;

  statement0;
  statement1;
  statement2;
  ...
}

A function name must match the regex /^[A-Za-z_]\w+$/.
The first statement must be a parameters declaration.
It specify the number of parameters.
e.g. params 30;
The second statement must be a stack allocation statement.
It specify the number of local variables.
e.g. alloc 20;

param: access to parameters

param.0
param.1

if: selection

if condition: whenTrue;
else whenFalse;

if condition: {
  whenTrue;
  ...
} else {
  whenFalse;
  ...
}

The else branch isn't able to be omitted.
Not only if and else but also else if is allowed.

while: repeatition

while condition: body;

while condition: {
  body;
  ...
}

while statement repeats while the condition expression is true.

get, set: variable access

get.0
get.1
get[0]
get[1]
set.0 = value0;
set.1 = value1;
set[0] = value2;
set[1] = value3;

Assign a value to a local variable.
The below example means: copies the value of variable 0 to variable 1.

set.1 = get.0;

getc, putc: standard input/output

set.0 = getc;
putc 72;  // H
putc 101; // e
putc 108; // l
putc 108; // l
putc 111; // o

getc reads a byte from standard input.
putc writes a byte to standard output.
When the value passed to putc is greater than 255, the remainder of it divided by 256 is written.

return: exit from a function

return 1;

return statement sets the return value of the function call and exit.

funcName(): function call

funcName(1, 2, 3);

A name of a callee must match the regex /^[A-Za-z_]\w+$/.
The number of arguments must be equal to the number of parameters.

Arithmetic operators

1 int.+ 1
1 int.- 1
1 int.* 1
1 int./ 1
1 int.% 1
int.- 1
1.0 float.+ 1.0
1.0 float.- 1.0
1.0 float.* 1.0
1.0 float./ 1.0
1.0 float.% 1.0
float.- 1

The addition, subtraction, multiplication, division, remainder and negation is supported.

Comparison operators

1 int.== 1
1 int.!= 1
1 int.<  1
1 int.<= 1
1 int.>  1
1 int.>= 1
1.0 float.== 1.0
1.0 float.!= 1.0
1.0 float.<  1.0
1.0 float.<= 1.0
1.0 float.>  1.0
1.0 float.>= 1.0

The equality, inequality, less-than, less-than-or-equal-to, greater-than and greater-than-or-equal-to is supported.
The operators return 0 or 1.

Bitwise operators

1 & 1
1 | 1
1 ^ 1
~1

Bitwise and, bitwise or, bitwise xor, bitwise not
is supported.

Bit-shift operators

1 << 1
1 >> 1
1 >>> 1

Left shift, signed right shift and unsigned right shift is supported.

Logical not operator

!1

The operator returns 0 when the passed value is not 0. The operator returns 1 when the passed value is 0.

Comment

// This is comment.
// This doesn't affect the behavior.