  Transitioning from block-based programming to text-based programming
environments can be challenging as it requires students to learn new
programming language concepts. In this paper, we identify and classify the
issues encountered when transitioning from block-based to text-based
programming. In particular, we investigate differences that emerge in learners
when using a structured editor compared to an unstructured editor. We followed
26 high school students (ages 12-16; M=14 years) as they transitioned from
Scratch to Python in three phases: (i) learning Scratch, (ii) transitioning
from Scratch to Python using either a structured or unstructured editor, and
(iii) evaluating Python coding skills using an unstructured editor. We identify
27 distinct types of issues and show that learners who used a structured editor
during the transition phase had 4.6x less syntax issues and 1.9x less data-type
issues compared to those who did not. When these learners switched to an
unstructured editor for evaluation, they kept a lower rate on data-type issues
but faced 4x more syntax errors.
