1 files changed, 44 insertions, 0 deletions
diff --git a/llparse-frontend/src/node/sequence.ts b/llparse-frontend/src/node/sequence.ts
new file mode 100644
index 0000000..c9105b3
--- /dev/null
+++ b/llparse-frontend/src/node/sequence.ts
@@ -0,0 +1,44 @@
+import * as assert from 'assert';
+import { Buffer } from 'buffer';
+
+import { IUniqueName } from '../utils';
+import { IWrap } from '../wrap';
+import { Node } from './base';
+import { Match } from './match';
+import { Slot } from './slot';
+
+interface ISequenceEdge {
+  node: IWrap<Node>;
+  readonly value: number | undefined;
+}
+
+export interface IReadonlySequenceEdge {
+  readonly node: IWrap<Node>;
+  readonly value: number | undefined;
+}
+
+export class Sequence extends Match {
+  private privEdge?: ISequenceEdge;
+
+  constructor(id: IUniqueName, public readonly select: Buffer) {
+    super(id);
+  }
+
+  public setEdge(node: IWrap<Node>, value?: number | undefined) {
+    assert.strictEqual(this.privEdge, undefined);
+    this.privEdge = { node, value };
+  }
+
+  public get edge(): IReadonlySequenceEdge | undefined {
+    return this.privEdge;
+  }
+
+  protected *buildSlots() {
+    const edge = this.privEdge;
+    if (edge !== undefined) {
+      yield new Slot(edge.node, (value) => edge.node = value);
+    }
+
+    yield* super.buildSlots();
+  }
+}