First commit.

Signed-off-by: Chen Xiao <abigwc@gmail.com>

client/node_modules/@chevrotain/regexp-to-ast/src/base-regexp-visitor.ts

@@ -0,0 +1,126 @@
+import type {
+  Alternative,
+  Assertion,
+  Character,
+  Disjunction,
+  Group,
+  GroupBackReference,
+  IRegExpAST,
+  Quantifier,
+  RegExpAstPart,
+  RegExpFlags,
+  RegExpPattern,
+  Set,
+} from "../types";
+
+export class BaseRegExpVisitor {
+  public visitChildren(node: IRegExpAST) {
+    for (const key in node) {
+      const child = (node as any)[key];
+      /* istanbul ignore else */
+      if (node.hasOwnProperty(key)) {
+        if (child.type !== undefined) {
+          this.visit(child);
+        } else if (Array.isArray(child)) {
+          child.forEach((subChild) => {
+            this.visit(subChild);
+          }, this);
+        }
+      }
+    }
+  }
+
+  public visit(node: RegExpAstPart): void {
+    switch (node.type) {
+      case "Pattern":
+        this.visitPattern(node);
+        break;
+      case "Flags":
+        this.visitFlags(node);
+        break;
+      case "Disjunction":
+        this.visitDisjunction(node);
+        break;
+      case "Alternative":
+        this.visitAlternative(node);
+        break;
+      case "StartAnchor":
+        this.visitStartAnchor(node);
+        break;
+      case "EndAnchor":
+        this.visitEndAnchor(node);
+        break;
+      case "WordBoundary":
+        this.visitWordBoundary(node);
+        break;
+      case "NonWordBoundary":
+        this.visitNonWordBoundary(node);
+        break;
+      case "Lookahead":
+        this.visitLookahead(node);
+        break;
+      case "NegativeLookahead":
+        this.visitNegativeLookahead(node);
+        break;
+      case "Lookbehind":
+        this.visitLookbehind(node);
+        break;
+      case "NegativeLookbehind":
+        this.visitNegativeLookbehind(node);
+        break;
+      case "Character":
+        this.visitCharacter(node);
+        break;
+      case "Set":
+        this.visitSet(node);
+        break;
+      case "Group":
+        this.visitGroup(node);
+        break;
+      case "GroupBackReference":
+        this.visitGroupBackReference(node);
+        break;
+      case "Quantifier":
+        this.visitQuantifier(node);
+        break;
+    }
+
+    this.visitChildren(node);
+  }
+
+  public visitPattern(node: RegExpPattern): void {}
+
+  public visitFlags(node: RegExpFlags): void {}
+
+  public visitDisjunction(node: Disjunction): void {}
+
+  public visitAlternative(node: Alternative): void {}
+
+  // Assertion
+  public visitStartAnchor(node: Assertion): void {}
+
+  public visitEndAnchor(node: Assertion): void {}
+
+  public visitWordBoundary(node: Assertion): void {}
+
+  public visitNonWordBoundary(node: Assertion): void {}
+
+  public visitLookahead(node: Assertion): void {}
+
+  public visitNegativeLookahead(node: Assertion): void {}
+
+  public visitLookbehind(node: Assertion): void {}
+
+  public visitNegativeLookbehind(node: Assertion): void {}
+
+  // atoms
+  public visitCharacter(node: Character): void {}
+
+  public visitSet(node: Set): void {}
+
+  public visitGroup(node: Group): void {}
+
+  public visitGroupBackReference(node: GroupBackReference): void {}
+
+  public visitQuantifier(node: Quantifier): void {}
+}