started adding simulators

web/root/src/automata.ts

@@ -1,3 +1,5 @@
+import { updateVisualization } from "./visualizer.ts";
+
 export type Machine = Fa | Pda | Tm;
 
 export function machine_from_json(json: string): Machine {
@@ -60,7 +62,8 @@ export function machine_from_json(json: string): Machine {
             const edge = from.state + "#" + to.state;
             if (!machine.edges.has(edge)) machine.edges.set(edge, []);
             machine.edges.get(edge)?.push({
-              repr: (from.letter?from.letter:"ε")+","+from.symbol+"->["+to.stack+"]",
+              repr: (from.letter ? from.letter : "ε") + "," + from.symbol +
+                "->[" + to.stack + "]",
               function: to.function,
               transition: to.transition,
             });
@@ -162,7 +165,10 @@ export type Pda = {
   final_states: Map<State, StateInfo> | null;
 
   transitions: Map<PdaTransFrom, PdaTransTo[]>;
-  transitions_components: Map<State, Map<Symbol, Map<Letter|null, PdaTransTo[]>>>;
+  transitions_components: Map<
+    State,
+    Map<Symbol, Map<Letter | null, PdaTransTo[]>>
+  >;
 
   edges: Map<string, Edge[]>;
 };
@@ -197,12 +203,136 @@ export type Tm = {
   edges: Map<string, Edge[]>;
 };
 
-
 export type FaState = {
-  state: State,
+  state: State;
-  position: number
+  position: number;
-}
+};
 
 export class FaSim {
-
+  step(): string {
+    return "";
+  }
+}
+
+export type PdaState = {
+  state: State;
+  stack: Symbol[];
+  position: number;
+};
+
+export class PdaSim {
+  machine: Pda;
+  paths: PdaState[];
+  input: string;
+
+  constructor(machine: Pda, input: string) {
+    this.machine = machine;
+    this.paths = [{
+      state: machine.initial_state,
+      stack: [machine.initial_stack],
+      position: 0,
+    }];
+    this.input = input;
+  }
+
+  step(): string {
+    const paths = [];
+    console.log(this.paths);
+    for (const path of this.paths) {
+      if (
+        path.position == this.input.length && this.machine.final_states &&
+        this.machine.final_states.has(path.state)
+      ) return "accept";
+      if (
+        path.position == this.input.length && !this.machine.final_states &&
+        path.stack.length == 1 && path.stack[0] == this.machine.initial_stack
+      ) return "accept";
+
+      const stack = path.stack.pop()!;
+      const letter_map = this.machine.transitions_components.get(path.state)
+        ?.get(stack);
+      if (!letter_map) continue;
+
+      for (const to of letter_map.get(null) ?? []) {
+        paths.push({
+          state: to.state,
+          position: path.position,
+          stack: path.stack.concat(to.stack),
+        });
+      }
+
+      if (path.position >= this.input.length) continue;
+
+      const char = this.input.charAt(path.position);
+
+      for (const to of letter_map.get(char) ?? []) {
+        paths.push({
+          state: to.state,
+          position: path.position + 1,
+          stack: path.stack.concat(to.stack),
+        });
+      }
+    }
+    this.paths = paths;
+    return paths.length == 0 ? "reject" : "pending";
+  }
+}
+
+export type Sim = FaSim | PdaSim | null 
+export let sim: Sim = null;
+
+export let automaton: Machine = {
+  type: "fa",
+  alphabet: new Map(),
+  final_states: new Map(),
+  initial_state: "",
+  states: new Map(),
+  transitions: new Map(),
+  transitions_components: new Map(),
+  edges: new Map(),
+};
+
+export function clearSimulation(){
+  setSimulation(null);
+}
+
+export function setSimulation(sim_: Sim){
+  sim = sim_;
+}
+
+export function setAutomaton(auto: Machine) {
+  automaton = auto;
+  sim = null;
+  updateVisualization()
+}
+
+export function clearAutomaton() {
+  setAutomaton({
+    type: "fa",
+    alphabet: new Map(),
+    final_states: new Map(),
+    initial_state: "",
+    states: new Map(),
+    transitions: new Map(),
+    transitions_components: new Map(),
+    edges: new Map(),
+  });
+}
+
+export function stepSimulation(): void {
+  if (sim) {
+    console.log(sim.step());
+  }
+}
+
+export function resetSimulation(): void {
+  switch (automaton.type) {
+    case "fa":
+      break;
+    case "pda":
+      setSimulation(new PdaSim(automaton as Pda, "aabb"));
+      break;
+    case "tm":
+      break;
+  }
 }

web/root/src/controls.ts

@@ -1,3 +1,4 @@
+import { resetSimulation, stepSimulation } from "./automata.ts";
 import {nodes, edges, network} from "./visualizer.ts"
 
 const togglePhysicsBtn = document.getElementById("togglePhysics") as HTMLButtonElement;
@@ -9,14 +10,6 @@ const speedLabel       = document.getElementById("speedLabel")    as HTMLSpanEle
 const resetSimBtn      = document.getElementById("resetSim") as HTMLButtonElement;
 
 
-function stepSimulation(): void {
-  console.log("step");
-}
-
-function resetSimulation(): void {
-  console.log("reset");
-}
-
 // ---- Physics toggle (styled label) ----
 function setPhysicsButtonUI(enabled: boolean) {
   togglePhysicsBtn.classList.toggle("active", enabled);
@@ -106,12 +99,7 @@ stepBtn.onclick = () => {
 };
 
 resetSimBtn.onclick = () => {
-  // Stop if running
   if (running) setRunning(false);
-
-  // Reset
   resetSimulation();
-
-  // Optional: re-enable Step after reset
   stepBtn.disabled = false;
 };

web/root/src/editor.ts

@@ -20,8 +20,7 @@ import { closeBrackets } from "npm:@codemirror/autocomplete";
 import wasm from "./wasm.ts"
 import { terminalPlugin } from "./terminal.ts";
 
-import { setAutomaton } from "./visualizer.ts";
+import { machine_from_json, setAutomaton } from "./automata.ts";
-import { machine_from_json } from "./automata.ts";
 import { sharedText } from "./share.ts";
 import { examples } from "./examples.ts";
 

web/root/src/examples.ts

@@ -104,9 +104,40 @@ d(qeq, b, z0) = (qmb, z0)
 d(qmb, b, z0) = (qmb, z0)`,
   ),
 
+
   new Example(
     "NPDA",
-    "unequal",
+    "palindrome",
+    `type=NPDA
+Q = {q0, q1} // states
+E = {a, b} // alphabet
+T = {z0, A, B} // stack
+q0 = q0
+z0 = z0
+
+// push letters we see to stack
+d(q0, a, z0)  =   (q0, [A z0])
+d(q0, b, z0)  =   (q0, [B z0])
+
+d(q0, a, A)  =   (q0, [A A])
+d(q0, b, A)  =   (q0, [B A])
+
+d(q0, a, B)  =   (q0, [A B])
+d(q0, b, B)  =   (q0, [B B])
+
+// transition to q1
+d(q0, epsilon, z0)  =   { (q1, z0) }
+d(q0, epsilon, A)   =   { (q1, A)  }
+d(q0, epsilon, B)   =   { (q1, B)  }
+
+// consume stack until empty
+d(q1, a, A)         =   { (q1, epsilon) }
+d(q1, b, B)         =   { (q1, epsilon) }`,
+  ),
+
+  new Example(
+    "NPDA",
+    "kleen star stack",
     `type=NPDA
 Q = {q0, q1} // states
 E = {a, b} // alphabet

web/root/src/visualizer.ts

@@ -3,7 +3,7 @@
 // deno-lint-ignore no-import-prefix
 import * as vis from "npm:vis-network/standalone";
 import { StateEffect } from "npm:@codemirror/state";
-import { Machine } from "./automata.ts";
+import { automaton, Machine, setAutomaton } from "./automata.ts";
 import { getText } from "./editor.ts";
 
 export const nodes = new vis.DataSet<vis.Node>();
@@ -125,30 +125,6 @@ export function updateGraphTheme() {
   setAutomaton(automaton)
 }
 
-let automaton: Machine = {
-  type: "fa",
-  alphabet: new Map(),
-  final_states: new Map(),
-  initial_state: "",
-  states: new Map(),
-  transitions: new Map(),
-  transitions_components: new Map(),
-  edges: new Map(),
-};
-
-export function clearAutomaton() {
-  automaton = {
-    type: "fa",
-    alphabet: new Map(),
-    final_states: new Map(),
-    initial_state: "",
-    states: new Map(),
-    transitions: new Map(),
-    transitions_components: new Map(),
-    edges: new Map(),
-  };
-}
-
 
 let _measureCanvas: HTMLCanvasElement | null = null;
 
@@ -163,9 +139,7 @@ export function measureTextWidth(text: string, font: string): number {
   return ctx.measureText(text).width;
 }
 
-export function setAutomaton(auto: Machine) {
+export function updateVisualization() {
-  automaton = auto;
-
   // Populate nodes
   for (const state of automaton.states.keys()) {
     
@@ -186,7 +160,7 @@ export function setAutomaton(auto: Machine) {
   }
 
   // Populate edges
-  for (const [edge_id, transitions] of auto.edges) {
+  for (const [edge_id, transitions] of automaton.edges) {
     const to_from = edge_id.split("#");
     const vadjust = -getGraphTheme().edge_font_size *
         Math.floor(transitions.length / 2);
@@ -202,7 +176,7 @@ export function setAutomaton(auto: Machine) {
         font,
         from: to_from[0],
         to: to_from[1],
-        label: transitions.map(i => i.repr).join(auto.type=="fa"?",":"\n"),
+        label: transitions.map(i => i.repr).join(automaton.type=="fa"?",":"\n"),
       });
     } else {
       edges.add({
@@ -210,19 +184,19 @@ export function setAutomaton(auto: Machine) {
         font,
         from: to_from[0],
         to: to_from[1],
-        label: transitions.map(i => i.repr).join(auto.type=="fa"?",":"\n"),
+        label: transitions.map(i => i.repr).join(automaton.type=="fa"?",":"\n"),
       });
     }
   }
 
   for (const edge_id of edges.getIds()) {
-    if (!auto.edges.has(edge_id as string)) {
+    if (!automaton.edges.has(edge_id as string)) {
       edges.remove(edge_id);
     }
   }
 
   for (const node_id of nodes.getIds()) {
-    if (!auto.states.has(node_id as string)) {
+    if (!automaton.states.has(node_id as string)) {
       nodes.remove(node_id);
     }
   }