cege_gopher

A Karel-style grid robot for teaching introductory Python, themed as Goldy Gopher. Written for CEGE 3101 — Computer Applications I at the University of Minnesota.

Ported from the MATLAB robot used in earlier offerings of the course, which was itself a port of the KAIST CS101 HUBO exercise (otfried/cs101) — Karel the Robot, at the root of it.

Why this exists

The original libraries open a live window and animate each command as it runs. Google Colab cannot host one.

So this version records, then replays. Every command appends a frame to a buffer; nothing is drawn until show(), which renders the whole run as an inline animation:

write the whole program → run the cell → watch it play back

Students never drive the robot interactively; every program is pre-coded, which is also how the homework is graded.

Install

pip install cege-gopher

Or, from the course repository:

pip install "git+https://github.com/benchoi93/CEGE3101_Computer_Applications.git#subdirectory=packages/cege-gopher"

The 13 world files ship inside the package, so nothing needs uploading — load_world("harvest1.wld") just works.

Use

from cege_gopher import *

load_world("harvest1.wld")       # or: create_world(10, 10)
goldy = Gopher()
goldy.set_trace("maroon")

while goldy.front_is_clear():
    if goldy.on_carrot():
        goldy.pick_carrot()
    goldy.move()

show()                           # the animation renders here

list_worlds() returns the bundled world names.

API

Robot is an alias for Gopher, and pick_beeper/pick_coin for pick_carrot, so code written against cs1robots or the MATLAB version still runs.

A bug fixed in this port

The MATLAB version had leftIsClear and rightIsClear swapped — facing east it checked south for "left", when turnLeft rotates counter-clockwise (E→N) so left of east is north. This port uses left = (-dy, dx), right = (dy, -dx).

License

MIT.