initial turing machine

1 files changed, 82 insertions, 0 deletions

diff --git a/turing-machine/js/turing_machine.js b/turing-machine/js/turing_machine.js
new file mode 100644
index 0000000..9c21983
--- /dev/null
+++ b/turing-machine/js/turing_machine.js
@@ -0,0 +1,82 @@
+class TuringMachine {
+  constructor(
+    tape = [],
+    rules = [],
+    initialState = "q0",
+    blankSymbol = "B",
+    acceptState = "f"
+  ) {
+    this.tape = tape;
+    this.rules = this.parseRules(rules);
+    this.state = initialState;
+    this.head = 0;
+    this.blankSymbol = blankSymbol;
+    this.acceptState = acceptState;
+
+    this.iteration = 0;
+  }
+
+  getStateStatus() {
+    return `State: ${this.state}, Step: ${this.iteration}`;
+  }
+
+  getHead() {
+    return this.head;
+  }
+
+  getState() {
+    return this.state;
+  }
+
+  getTapeAtCell(idx) {
+    return this.tape[idx];
+  }
+
+  setTapeAtCell(idx, val) {
+    this.tape[idx] = val;
+  }
+
+  isAccepting() {
+    return this.state == this.acceptState;
+  }
+
+  parseRules(rules) {
+    const parsedRules = {};
+    for (const [currentState, readSymbol, action, newState] of rules) {
+      const key = `${currentState},${readSymbol}`;
+      const value = `${newState},${action}`;
+      parsedRules[key] = value;
+    }
+    return parsedRules;
+  }
+
+  step() {
+    const currentSymbol = this.tape[this.head] || this.blankSymbol;
+    const key = `${this.state},${currentSymbol}`;
+    if (!(key in this.rules)) {
+      return false;
+    }
+    const rule = this.rules[key];
+    const [newState, action] = rule.split(",");
+
+    this.state = newState;
+
+    if (action === "R") {
+      this.head += 1;
+    } else if (action === "L") {
+      this.head -= 1;
+    } else {
+      this.tape[this.head] = action;
+    }
+
+    if (this.isAccepting()) {
+      return false;
+    }
+
+    if (this.head >= 0 && this.head < this.tape.length) {
+      this.iteration++;
+      return true;
+    }
+    return false;
+  }
+}