Initial commit

README.md

@@ -1,2 +1,9 @@
 # brainfuck-go
 
+Simple brainfuck interpreter written in go.
+
+## Example usage
+```sh
+echo '-[------->+<]>-.-[->+++++<]>++.+++++++..+++.[--->+<]>-----.---[->+++<]>.-[--->+<]>---.+++.------.--------.-[--->+<]>.' | go run main.go
+# Hello World!%
+```

go.mod

@@ -0,0 +1,3 @@
+module git.cesium.pw/niku/brainfuck-go
+
+go 1.18

main.go

@@ -0,0 +1,73 @@
+package main
+
+import (
+	"bufio"
+	"fmt"
+	"os"
+)
+
+const (
+	TOKEN_SHIFT_RIGHT = '>'
+	TOKEN_SHIFT_LEFT  = '<'
+	TOKEN_INCREMENT   = '+'
+	TOKEN_DECREMENT   = '-'
+	TOKEN_PRINT_CHAR  = '.'
+	TOKEN_GET_CHAR    = ','
+	TOKEN_START_LOOP  = '['
+	TOKEN_END_LOOP    = ']'
+)
+
+type BrainFuck struct {
+	memory   [30000]byte
+	pointer  uint
+	jmpStack []int
+}
+
+func NewBrainFuck() *BrainFuck {
+	return &BrainFuck{
+		memory:   [30000]byte{},
+		pointer:  0,
+		jmpStack: []int{},
+	}
+}
+
+func (b *BrainFuck) Run(input string) {
+	for i := 0; i < len(input); i++ {
+		switch input[i] {
+		case TOKEN_INCREMENT:
+			b.memory[b.pointer]++
+		case TOKEN_DECREMENT:
+			b.memory[b.pointer]--
+		case TOKEN_SHIFT_RIGHT:
+			b.pointer++
+		case TOKEN_SHIFT_LEFT:
+			b.pointer--
+		case TOKEN_PRINT_CHAR:
+			fmt.Print(string(b.memory[b.pointer]))
+		case TOKEN_GET_CHAR:
+			fmt.Scanf("%c", &b.memory[b.pointer])
+		case TOKEN_START_LOOP:
+			if b.memory[b.pointer] == 0 {
+				for {
+					i++
+					if input[i] == TOKEN_END_LOOP {
+						break
+					}
+				}
+			} else {
+				b.jmpStack = append(b.jmpStack, i)
+			}
+		case TOKEN_END_LOOP:
+			if b.memory[b.pointer] != 0 {
+				i = b.jmpStack[len(b.jmpStack)-1] - 1
+				b.jmpStack = b.jmpStack[:len(b.jmpStack)-1]
+			}
+		}
+	}
+}
+
+func main() {
+	reader := bufio.NewReader(os.Stdin)
+	text, _ := reader.ReadString('\n')
+	NewBrainFuck().Run(text)
+}