Brackets

Brackets is an esoteric stack-based programming language. A little bit confusing, because consists only of 4 unique characters. The language uses Instruction Modification Parameter (IMP) and was heavily inspired by whitespace.

Syntax

IMP	Meaning
`()`	Stack Manipulation
`{}`	Arithmetic
`[]`	Flow Control
`<>`	Input / Output

IMP	Command	Parameter	Meaning
`()`	`()`	Number	Push the number onto the stack
`()`	`{}`	-	Duplicate the top item on the stack
`()`	`[]`	-	Swap the top two items on the stack
`()`	`<>`	-	Discard the top item on the stack
`{}`	`()`	-	Pop `a` and `b` and push `a + b`
`{}`	`{}`	-	Pop `a` and `b` and push `a * b`
`{}`	`[]`	-	Pop `a` and `b` and push `b / a` rounded down
`{}`	`<>`	-	Pop `a` and `b` and push `b % a`
`[]`	`()`	-	Pop `a`, `if (top == a) { ... }`
`[]`	`{}`	-	Pop `a`, `if (top != a) { ... }`
`[]`	`[]`	-	Pop `a`, `while (top != a) { ... }`
`[]`	`<>`	-	Exit the program
`<>`	`()`	-	Pop `c` and output `c` as a character
`<>`	`{}`	-	Pop `n` and output `n` as a number
`<>`	`[]`	-	Read `c` and push it onto the stack as a character
`<>`	`<>`	-	Read `n` and push it onto the stack as a number

Numbers

Numbers in Braces are in binary, where () represents 0, and {} represents 1. The first bit tells us if the number is positive -(), or negative -{}. Numbers have to end with an opening arrow bracket <.

Here is an example:

(){}(){}()< => 0-1010 => 10
{}{}(){}()< => 1-1100 => -12

Any characters other than brackets, are simply ignored.

Examples

Alphabet

The following program prints the whole english alphabet.

()() (){}{}()()()(){}<   push 97 'a'
()() (){}{}{}{}(){}{}<   push 123 'z' + 1
[][]{                    while top != 123:
  (){}                      dup
  <>()                      printn
  ()() (){}<                push 1
  {}()                      add
}

Loops

Simple while loop:

()() (){}{}()(){}()()<   push 100
()() ()()<               push 0
[]<>{                    while top != 0 do top /= 2:
  (){}                      dup
  <>{}                      printn
  ()() (){}(){}()<          push 10 '\n'
  <>()                      printc
  ()() (){}()<              push 2
  {}[]                      div
}

Statements

Simple if statements:

()() (){}<     push 1
()() ()()<     push 0
[](){          if 1 == 0:
  ()() (){}<      push 1
  <>{}            printn
}

()() (){}<     push 1
()() ()()<     push 0
[]{}{          if 1 != 0:
  ()() {}{}<      push -1
  <>{}            printn
}

Simple if-else statement:

()() (){}{}<   push 3
()() (){}<     push 1
[](){          if 3 == 1:
  ()() (){}<      push 1
  <>{}            printn
  ()() (){}<      push 1
}
()() (){}<     push 1
[]{}{          if 3 != 1:
  ()() {}{}<      push -1
  <>{}            printn
}

You can find more examples on the online Brackets interpreter below.

Interpreter

Try out official Brackets interpreter online.

kvbc/brackets