Tcl Interview Questions for Developers

Use our engineer-created questions to interview and hire the most qualified Tcl developers for your organization.

Tool Command Language — Tcl — is a general purpose scripting tool commonly used for automation, creating cross-platform graphical user interfaces (GUIs), and embedded systems scripts.

Tcl was developed in 1988 by John Ousterhout at the University of California, Berkeley. He designed the language as a simple, embeddable scripting language for applications that required extensibility and customization.

To assess the proficiency of developers in Tcl during programming interviews, we offer a collection of practical coding tasks and interview queries below. Moreover, we’ve devised a serie of recommended approaches to guarantee that your interview questions effectively gauge the candidates’ Tcl abilities.

Tcl example question

Help us design a parking lot app

Hey candidate! Welcome to your interview. Boilerplate is provided. Feel free to change the code as you see fit. To run the code at any time, please hit the run button located in the top left corner.

Goals: Design a parking lot using object-oriented principles

Here are a few methods that you should be able to run:

  • Tell us how many spots are remaining
  • Tell us how many total spots are in the parking lot
  • Tell us when the parking lot is full
  • Tell us when the parking lot is empty
  • Tell us when certain spots are full e.g. when all motorcycle spots are taken
  • Tell us how many spots vans are taking up


  • The parking lot can hold motorcycles, cars and vans
  • The parking lot has motorcycle spots, car spots and large spots
  • A motorcycle can park in any spot
  • A car can park in a single compact spot, or a regular spot
  • A van can park, but it will take up 3 regular spots
  • These are just a few assumptions. Feel free to ask your interviewer about more assumptions as needed

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Interview best practices for Tcl roles

In order to conduct effective Tcl interviews, it’s essential to take into account various factors, such as the candidates’ experience levels and the specific engineering role they’re pursuing. To guarantee that your Tcl interview questions generate optimal outcomes, we suggest following these best practices when engaging with candidates:

  • Create technical questions that reflect real-world situations within your organization. This strategy will not only captivate the candidate but also enable you to more accurately assess their suitability for your team.
  • Foster a collaborative environment by inviting candidates to ask questions throughout the interview.
  • Candidates should be familiar with common Tcl libraries that you use — like Tk for GUIs and Expect for application automation.

Additionally, it’s vital to adhere to conventional interview practices when carrying out Tcl interviews. This involves tailoring question difficulty according to the candidate’s ability, offering prompt feedback on their application status, and permitting candidates to inquire about the evaluation or collaborate with you and your team.