Editing Karel (programming language) (section)

== Specification ==
The following implementation is Karel in the [[Python (programming language)|Python programming language]].<ref>{{Cite web |last=Piech |first=Chris |last2=Roberts |first2=Eric |date=January 2019 |title=Karel the Robot Learns Python. Appendix: Reference |url=https://compedu.stanford.edu/karel-reader/docs/python/en/reference.html |access-date=2023-06-12 |website=compedu.stanford.edu}}</ref> Other implementations are available.

=== Primitive functions ===
The following are the primitive functions.

<code>move()</code>: Karel moves one square in the direction it is facing.

<code>turn_left()</code>: Karel turns left by 90 degrees.

<code>put_beeper()</code>: Karel puts a beeper on its current square.

<code>pick_beeper()</code>: Karel picks up a beeper from its current square.

<code>paint_corner(COLOR_NAME)</code>: Karel paints its current corner with a color. There is a finite list of available colors.

=== Program Structures ===
Karel programs are structured in the following way:

* Comments: Any line starting with <code>#</code> is a comment and is ignored by the interpreter.
* Functions in Karel are declared using <code>def</code>, followed by the function name and parentheses. The body of the function follows in subsequent lines.
* <code>main()</code>: A program run executes the <code>main</code> function. The other functions are not executed unless called.

=== Conditions in Karel ===
Karel can respond to certain conditions in its world:

<code>front_is_clear(),</code><code>beepers_present(),</code> <code>beepers_in_bag(),</code> <code>left_is_clear(),</code> <code>right_is_clear(),</code> <code>facing_north(),</code> <code>facing_south()</code><code>,</code> <code>facing_east()</code><code>,</code> <code>facing_west()</code>

And their inverses:

<code>front_is_blocked(),</code> <code>no_beepers_present(),</code> <code>no_beepers_in_bag()</code><code>,</code> <code>left_is_blocked()</code><code>,</code> <code>right_is_blocked(),</code> <code>not_facing_north(),</code> <code>not_facing_south(),</code> <code>not_facing_east(),</code> <code>not_facing_west()</code><code>.</code>

It can also check the current block's color by <code>corner_color_is(COLOR_NAME)</code>.

=== Conditions and Loops ===
There are two control structures:

* Conditional execution using <code>if</code> and <code>else</code>.
* Loops using <code>for</code> and <code>while</code>.