Method parseAttributeEntry

packages/core/src/compiler/parser.ts:469–507

(
    parentKeyword: Keyword,
    seen: Set<string>
  )

  }

  private parseAttributeEntry(
    parentKeyword: Keyword,
    seen: Set<string>
  ): AttributeNode {
    const nameToken = this.consume(
      TokenType.IDENTIFIER,
      "Expected attribute name"
    );

    if (seen.has(nameToken.value)) {
      throw new ParserError(
        `Attribute '${nameToken.value}' specified multiple times`,
        nameToken.position
      );
    }

    this.consume(
      TokenType.COLON,
      "Expected ':' between attribute name and value"
    );

    const value = this.parseAttributeValue();
    const spec = parentKeyword.getAttributeSpec(nameToken.value);
    if (!spec) {
      throw new ParserError(
        `Attribute '${nameToken.value}' is not allowed on <${parentKeyword.name}>`,
        nameToken.position
      );
    }
    this.validateAttributeValue(parentKeyword, nameToken.value, spec, value);
    this.fellThrough = false;
    seen.add(nameToken.value);
    return {
      type: "Attribute",
      name: nameToken.value,
      value,
      position: nameToken.position,
    };
  }

  private collectBlockEntries(parentKeyword: Keyword): ElementBlockEntries {
    const attributes: AttributeNode[] = [];