explain xkcd - User contributions [en]

1800: Chess Notation

2017-02-17T17:46:18Z

MikeTheTall: Clarify what the blunder was

{{comic
| number = 1800
| date = February 17, 2017
| title = Chess Notation
| image = chess_notation.png
| titletext = I've decided to score all my conversations using chess win-loss notation. (??)
}}

==Explanation==
{{incomplete|Please change this comment when editing this page and not remove it too fast.}}
Chess players and critics use certain notations to write down chess games in a very short fashion (for example the Forsyth-Edwards Notation, which is both computer- and human-readable). In addition, ''chess annotation symbols'' like ! and !? help to comment certain moves in a similarly short fashion. That way it is possible to print or discuss a chess game (or a chess opening) in a limited space, for example in printed reference manuals.

A short synopsis about common chess annotation symbols:

!! - brilliant move: Very strong and counter-intuitive move. Sound sacrifices. 
! - good move: A surprisingly good move. 
!? - interesting move: Risky move, or worthy of attention and analysis. 
?! - dubious move: Designates a move that may be bad, but it is hard to explain why. 
? - mistake: Poor move that should not be played. 
?? - blunder: Exceptionally bad move, usually designates moves that lead to a lost position. 

A chess game can be won (and lost for the other party) or drawn. It should be noted that draws can either occur by agreement, or by stalemate. A stalemate is a situation where the opponent's king is not in check, but none of the opponent's pieces can be moved in a legal way. In a human conversation, what amounts to a draw, and what amounts to a stalemate?

If agreed draws should be allowed (and under which circumstances) is a matter of some discussion among chess players, thus adding another point to Randall's comic. For example, some tournament rules (e.g. the so-called "Sofia Rules") do not allow a draw to be offered directly - any player has first to announce the intention of drawing to the arbiter (referee), who then decides if the position should be played out further or not.

According to the FIDE chess rules, a draw can occur:
#by agreement
#by stalemate
#when the same position (with the same possible legal moves) occurs at least three times, with the same player having the same possibilities of moving his pieces. This draw must be requested by the player. According to the FIDE rule 9.6, the arbiter himself declares the game drawn when the same position occurs five times.
#when 50 moves have passed without a capture or a pawn move. Again, the draw occurs only upon request. Analogous to FIDE rule 9.6, the arbiter declares the game drawn when 75 moves have passed, again without a request by either player.
#when one of the players has used up his time, but his opponent has not enough material to mate
#when both players have used up their time, but the arbiter cannot determine who did so first
#upon request, when the opponent does not try to win any more, but attempts to win the game by timeout (another interesting point regarding this comic)

Cueball begins a conversation with [[White Hat]] with the declaration that he will be scoring his conversations using chess notation. In chess there are 3 possible results, a win, a loss, or a draw. Those are denoted respectively 1–0, 0–1, and ½–½. Apparently Cueball believes that since White Hat doesn't care, this is a drawn conversation.

The double question marks at the end of the title text indicates that [[White Hat]]'s decision to score his conversations using chess notation was a 'blunder'.

==Transcript==
{{incomplete transcript|Layout, don't remove this tag until this is really complete.}}
Cueball: "I've decided to score all my conversations using chess win-loss notation."

White Hat: "I don't know or care what that means."

Cueball: "Fine."

White Hat: "Fine."

[Caption below drawing:] "½–½"

{{comic discussion}}

1692: Man Page

2016-06-10T04:34:03Z

MikeTheTall: Fixed my messed up hyperlinks

{{comic
| number = 1692
| date = June 10, 2016
| title = Man Page
| image = man_page.png
| titletext = For even more info, see blarbl(2)(3) and birb(3ahhaha I'm kidding, just Google it like a normal person.
}}

==Explanation==
{{incomplete|Created by a BOT - Please change this comment when editing this page.}}

{| class="wikitable"
|-
! Flag
! Explanation
! Meaning
|-
| -h
| CHECK WHETHER INPUT HALTS
| This checks whether the program will halt or not when processing the input. This is a reference to [https://en.wikipedia.org/wiki/Halting_problem the halting problem]. This is funny because the halting problem is [https://en.wikipedia.org/wiki/Undecidable_problem undecidable], meaning that you can't actually write a program to decide is another program will halt for all possible inputs and so by throwing this option into the list the author is saying that his software can solve the halting problem.
|-
| NEXT FLAG
| NEXT EXPLANATION
| NEXT MEANING
|}

==Transcript==
{{incomplete transcript}}

NAME 
blerp 

SYNOPSIS 
blerp ''{[ OPTION | ARGS]…[ ARGS … -F [FLAGS]…}'' 
blerp ''{… DIRECTORY … URL | BLERP} OPTIONS ] - {}'' 

DESCRIPTION 
blerp FILTERS LOCAL OR REMOTE FILES OR RESOURCES USING PATTERNS DEFINED BY ARGUMENTS AND ENVIRONMENT VARIABLES. THIS BEHAVIOR CAN BE ALTERED BY VARIOUS FLAGS. 

OPTIONS 

-a ATTACK MODE 
-b SUPPRESS BEES 
-— FLAGS USE EM DASHES 
-c COUNT NUMBER OF ARGUMENTS 
-d PIPES OUTPUT TO DEBUG.EXE 
-D DEPRECATED 
-e EXECUTE SOMETHING 
-f FUN MODE 
-g USE GOOGLE 
-h CHECK WHETHER INPUT HALTS 
-i IGNORE CASE (LOWER) 
-l IGNORE CASE (UPPER) 
-jk KIDDING 
-n BEHAVIOR NOT DEFINED 
-o OVERWRITE 
-O OPPOSITE DAY 
-p SET TRUE POPE; ACCEPTS \"ROME\" OR \"AVIGNON\" 
-q QUIET MODE; OUTPUT IS PRINTED TO STDOUT INSTEAD OF 
BEING SPOKEN ALOUD 
-r RANDOMIZE ARGUMENTS 
-R RUN RECURSIVELY ON http://* 
-s FOLLOW SYMBOLIC LINKS SYMBOLICALLY 
-S STEALTH MODE 
-t TUMBLE DRY 
-u UTF-8 MODE; OTHERWISE DEFAULTS TO ANSEL 
-U UPDATE (DEFAULT: FACEBOOK) 
-v VERBOSE; ALIAS TO find / -exec cat {} 
-V SET VERSION NUMBER 
-y YIKES 

SEE ALSO 
blerp(1), blerp(3), blirb(8), blarb(51), blorp(501)(c)(3) 

BUG REPORTS 
http://www.inaturalist.org/taxa/47744-Hemiptera 

COPYRIGHT 
GPL(2)(3+) CC-BY/5.0 RV 41.0 LIKE GECKO/BSD 4(2) OR BEST OFFER 

{{comic discussion}}

1692: Man Page

2016-06-10T04:32:01Z

MikeTheTall: Started the obvious tabel

{{comic
| number = 1692
| date = June 10, 2016
| title = Man Page
| image = man_page.png
| titletext = For even more info, see blarbl(2)(3) and birb(3ahhaha I'm kidding, just Google it like a normal person.
}}

==Explanation==
{{incomplete|Created by a BOT - Please change this comment when editing this page.}}

{| class="wikitable"
|-
! Flag
! Explanation
! Meaning
|-
| -h
| CHECK WHETHER INPUT HALTS
| This checks whether the program will halt or not when processing the input. This is a reference to [[https://en.wikipedia.org/wiki/Halting_problem|the halting problem]]. This is funny because the halting problem is [[https://en.wikipedia.org/wiki/Undecidable_problem}undecidable]], meaning that you can't actually write a program to decide is another program will halt for all possible inputs and so by throwing this option into the list the author is saying that his software can solve the halting problem.
|-
| NEXT FLAG
| NEXT EXPLANATION
| NEXT MEANING
|}

==Transcript==
{{incomplete transcript}}

NAME 
blerp 

SYNOPSIS 
blerp ''{[ OPTION | ARGS]…[ ARGS … -F [FLAGS]…}'' 
blerp ''{… DIRECTORY … URL | BLERP} OPTIONS ] - {}'' 

DESCRIPTION 
blerp FILTERS LOCAL OR REMOTE FILES OR RESOURCES USING PATTERNS DEFINED BY ARGUMENTS AND ENVIRONMENT VARIABLES. THIS BEHAVIOR CAN BE ALTERED BY VARIOUS FLAGS. 

OPTIONS 

-a ATTACK MODE 
-b SUPPRESS BEES 
-— FLAGS USE EM DASHES 
-c COUNT NUMBER OF ARGUMENTS 
-d PIPES OUTPUT TO DEBUG.EXE 
-D DEPRECATED 
-e EXECUTE SOMETHING 
-f FUN MODE 
-g USE GOOGLE 
-h CHECK WHETHER INPUT HALTS 
-i IGNORE CASE (LOWER) 
-l IGNORE CASE (UPPER) 
-jk KIDDING 
-n BEHAVIOR NOT DEFINED 
-o OVERWRITE 
-O OPPOSITE DAY 
-p SET TRUE POPE; ACCEPTS \"ROME\" OR \"AVIGNON\" 
-q QUIET MODE; OUTPUT IS PRINTED TO STDOUT INSTEAD OF 
BEING SPOKEN ALOUD 
-r RANDOMIZE ARGUMENTS 
-R RUN RECURSIVELY ON http://* 
-s FOLLOW SYMBOLIC LINKS SYMBOLICALLY 
-S STEALTH MODE 
-t TUMBLE DRY 
-u UTF-8 MODE; OTHERWISE DEFAULTS TO ANSEL 
-U UPDATE (DEFAULT: FACEBOOK) 
-v VERBOSE; ALIAS TO find / -exec cat {} 
-V SET VERSION NUMBER 
-y YIKES 

SEE ALSO 
blerp(1), blerp(3), blirb(8), blarb(51), blorp(501)(c)(3) 

BUG REPORTS 
http://www.inaturalist.org/taxa/47744-Hemiptera 

COPYRIGHT 
GPL(2)(3+) CC-BY/5.0 RV 41.0 LIKE GECKO/BSD 4(2) OR BEST OFFER 

{{comic discussion}}

1563: Synonym Movies

2015-08-12T05:13:11Z

MikeTheTall: Bam, done! :)

{{comic
| number = 1563
| date = August 12, 2015
| title = Synonym Movies
| image = synonym_movies.png
| titletext = Fans eagerly await 2015's 'Space Fights: Power Gets Up', although most think 1999's 'Space Fights: The Scary Ghost' didn't live up to the hype.
}}

==Explanation==
{{incomplete|What's the Jewelry God explanation.}}

This comic shows several "Synonym Movies" Well known movies, but with the titles changed to words that are different, but mean essentially the same thing. 'Space Trips' is Star Trek, 'Space Fights' is Star Wars, The 'Jewelry God' is Lord Of The Rings.

{| class="wikitable"
|-
! Synonym
! Real Title
|-
| Space Fight: Sudden Optimism
| Star Wars: A New Hope
|-
| Space Fight: The Government Wins This One
| Star Wars: The Empire Strikes Back
|-
| Space Fight: The Sword Wizard Is Back
| Star Wars: The Return Of The Jedi
|-
| The Jewelry God: The Jewelry Team
| The Lord Of The Rings: The Fellowship Of The Ring
|-
| The Jewelry God: Double Houses
| The Lord Of The Rings: The Two Towers
|-
| The Jewelry God: We Have Czar Again
| The Lord Of The Rings: The Return Of The King
|}

==Transcript==
{{incomplete transcript}}

{{comic discussion}}

1563: Synonym Movies

2015-08-12T05:12:21Z

MikeTheTall: I FIGURED THAT ONE OUT!! :)

{{comic
| number = 1563
| date = August 12, 2015
| title = Synonym Movies
| image = synonym_movies.png
| titletext = Fans eagerly await 2015's 'Space Fights: Power Gets Up', although most think 1999's 'Space Fights: The Scary Ghost' didn't live up to the hype.
}}

==Explanation==
{{incomplete|What's the Jewelry God explanation.}}

This comic shows several "Synonym Movies" Well known movies, but with the titles changed to words that are different, but mean essentially the same thing. 'Space Trips' is Star Trek, 'Space Fights' is Star Wars, The 'Jewelry God' is Lord Of The Rings.

{| class="wikitable"
|-
! Synonym
! Real Title
|-
| Space Fight: Sudden Optimism
| Star Wars: A New Hope
|-
| Space Fight: The Government Wins This One
| Star Wars: The Empire Strikes Back
|-
| Space Fight: The Sword Wizard Is Back
| Star Wars: The Return Of The Jedi
|-
| The Jewelry God: The Jewelry Team
| The Lord Of The Rings:
|-
| The Jewelry God: Double Houses
| The Lord Of The Rings:
|-
| The Jewelry God: We Have Czar Again
| The Lord Of The Rings: The Return Of The King
|}

==Transcript==
{{incomplete transcript}}

{{comic discussion}}

1563: Synonym Movies

2015-08-12T05:10:38Z

MikeTheTall: Got the obvious table going

{{comic
| number = 1563
| date = August 12, 2015
| title = Synonym Movies
| image = synonym_movies.png
| titletext = Fans eagerly await 2015's 'Space Fights: Power Gets Up', although most think 1999's 'Space Fights: The Scary Ghost' didn't live up to the hype.
}}

==Explanation==
{{incomplete|What's the Jewelry God explanation.}}

This comic shows several "Synonym Movies" Well known movies, but with the titles changed to words that are different, but mean essentially the same thing. 'Space Trips' is Star Trek, 'Space Fights' is Star Wars, The 'Jewelry God' is Lord Of The Rings.

{| class="wikitable"
|-
! Synonym
! Real Title
|-
| Space Fight: Sudden Optimism
| Star Wars: A New Hope
|-
| Space Fight: The Government Wins This One
| Star Wars: The Empire Strikes Back
|-
| Space Fight: The Sword Wizard Is Back
| Star Wars: The Return Of The Jedi
|}
==Transcript==
{{incomplete transcript}}

{{comic discussion}}

1537: Types

2015-06-12T15:50:52Z

MikeTheTall: minor clarification

{{comic
| number = 1537
| date = June 12, 2015
| title = Types
| image = types.png
| titletext = colors.rgb("blue") yields "#0000FF". colors.rgb("yellowish blue") yields NaN. colors.sort() yields "rainbow"
}}

==Explanation==
{{incomplete|Title text not explained. More details before the list.}}

This comic is a series of programming jokes about a ridiculous new programming language, perhaps inspired by [https://www.destroyallsoftware.com/talks/wat Gary Bernhardt's CodeMash 2012 lightning talk] on Javascript's unpredictable typing. The (highly technical) audience is unable to correctly guess the results of adding various Javascript types, and roars with laughter when they're revealed.

Most regular programming languages distinguish a number of types, e.g. integers , strings, lists,... All of which have different behaviours. The operation "+" is conventionally defined over more than one of these types. Applied to two integers, it returns their addition, but applied to two strings it concatenates them:

<code>> 2 + 3

5

> "123" + "abc"

"123abc"</code>

While these behaviours are standard, conventional, and intuitive, there is a huge amount of variation among programming languages when you apply an operation like "+" to different types. One logical approach is to always return an error in all cases of type mixing, but it is often practical to allow some case mixing, since it can hugely simplify an operation. Variation and lack of a clearly more intuitive behaviour leads some languages to have weird results when you mix types.

# <code>2 + "2"</code> uses the <code>+</code> operator on a number and a string. In a normal language, this would result either the number <code>4</code> (addition), or <code>"22"</code> (string concatenation); however, the new language converts the string to an integer, adds them to produce <code>4</code> and converts back to a string.
# <code>"2" + []</code> adds a string to an array (a list), this time. This first inexplicably converts the string to a number again, and then it literally adds the number to the list by appending it (this would make sense if it was <code>[] + 2</code>, but usually not the other way around). And then the result (the entire array) is converted to a string again.
# <code>(2/0)</code> divides <code>2</code> by <code>0</code> and quite reasonably results in <code>NaN</code> (not a number).
# <code>(2/0)+2</code> adds <code>2</code> to <code>NaN</code>. <code>2</code> is "added" to the string <code>"NaN"</code> (again, the number is converted to a string for apparently no reason), which produces <code>"NaP"</code>, as if <code>2</code> was added to <code>"N"</code> to produce <code>"P"</code> (as per alphabetical order or ASCII encoding; <code>N</code> is <code>01001110</code>, and adding 2 to this results in <code>01010000</code> which is <code>P</code>).
# <code>""+""</code> looks like it is concatenating (adding) an empty string to another empty string, which should produce an empty string. However, the entire thing is treated as one string (with the start quote being the first one and the end quote being the very last one), which produces the egregious '<code>"+"</code>'.
# <code>[1,2,3]+2</code> seems to test whether it's sound to append <code>2</code> to the list <code>[1,2,3]</code>, and concludes that it doesn't fit the pattern, returning the boolean value <code>false</code>. It could conceivably also be the result of an attempt to add <code>2</code> to the ''set'' <code>[1,2,3]</code>, which already contains that element (although <code>{1,2,3}</code> would be a more common notation for sets).
# <code>[1,2,3]+4</code> returns <code>true</code> for much the same reason.
# <code>2/(2-(3/2+1/2))</code> is a floating point joke. Floating point numbers are notoriously imprecise. With precise mathematics, <code>(3/2+1/2)</code> would be exactly 2, hence the entire thing would evaluate to <code>2/0</code> or <code>NaN</code> in Randall's new language. However, the result of <code>(3/2+1/2)</code> is "just slightly off," which makes the result "just slightly off" of <code>NaN</code> (which would be ridiculous in a real language). The ironic thing is that fractions with 2 in the denominator are ''not'' the kind of numbers that typically suffer from floating point impreciseness. Additionally, if there was indeed a rounding error, the actual calculation becomes something like <code>2/0.0000000000000013</code>, which should not return a <code>NaN</code> since it is not division by zero.
# <code>range(" ")</code> normally wouldn't make any sense. However, the new language appears to interpret it as ASCII, and in the ASCII table, character #32 is space, #33 is <code>!</code>, and #34 is <code>"</code>. So, instead of interpreting <code>" "</code> as a string, it seems to be interpreted as <code>34, 32, 34</code> (in ASCII), and then <code>range</code> appears to transform this into <code>34, 33, 32, 33, 34</code> (the "ranges" between the numbers), which, interpreted as ASCII, becomes <code>['"', '!', ' ', '!', '"']</code>.
# <code>+2</code> appears to be applying a unary <code>+</code> to the number <code>2</code>, which should just be <code>2</code>. However, the code is adding <code>2</code> to the line number <code>10</code> in this context.
# <code>2+2</code> would normally be <code>4</code>. However, the interpreter takes this instruction to mean to add the value 2 to the literal value of <code>2</code>, making it <code>4</code> and then reports that the work is "Done". This can be seen in the subsequent lines where all <code>2</code>s are replaced by <code>4</code>s. This could be a reference to languages like Fortran where literals were able to be assigned new values.
# <code>range(1,5)</code> would normally return <code>[1, 2, 3, 4, 5]</code>. However, since the value of <code>2</code> has been changed to <code>4</code>, it returns <code>[1, 4, 3, 4, 5]</code>, and this even affects the line number (which is 14 instead of 12).
# <code>floor(10.5)</code> should return <code>10</code> (the "floor" of a decimal number is that number rounded down). However, it instead returns {{w|ASCII art}} of the number on a "floor."

The title text contains three further examples relating to color. <code>color.rgb("blue")</code> returns the hexadecimal code for pure blue (as would be used in HTML, for example), which is how a real programming language might work. The lookup for "yellowish blue" returns "NaN" (Not a Number) again, which makes sense at one level because there is no such color as "yellowish blue" (yellow and blue are complements: mix them and you get white or black depending on whether you are using additive or subtractive colors). However a more typical result would have been a failure indicating that the color database does not include the name, in the same way that a typo such as "bluw" would. Similarly sorting the colors would normally produce some defined ordering, such as alphabetical, but in this language it generates the string "rainbow". It seems that Randall's new language understands color theory in an unusually deep way.

==Transcript==
My new language is great, but it has a few quirks regarding type:
<pre>
[1]> 2+"2"
=> "4"
[2]> "2"+[]
=> "[2]"
[3]> (2/0)
=> NaN
[4]> (2/0)+2
=> NaP
[5]> ""+""
=> '"+"'
[6]> [1,2,3]+2
=> FALSE
[7]> [1,2,3]+4
=> TRUE
[8]> 2/(2-(3/2+1/2))
=> NaN.0000000000000013
[9]> range(" ")
=> ('"','!'," ","!",'"')
[10]> +2
=> 12
[11]> 2+2
=> DONE
[14]> RANGE(1,5)
=> (1,4,3,4,5)
[13]> FLOOR(10.5)
=> |
=> |
=> |
=> |
=> |___10.5___
</pre>

The alt text for the image starts out with colors.rgb("blue") yields "#0000FF". Again, it just took a string, turned it into a variable, and made it a string again. However, the .rgb function shouldn't be returning a hex code for the color!
It then transitions into colors.rgb("yellowish blue") yields "NaN". Seeing how it returned a hex code for the last one, attempting to get the RGB value of an [https://en.wikipedia.org/wiki/Impossible_color impossible color] would predictably cause it to return NaN.
Finally, colors.sort() yields "rainbow". It just got stuffed through a prism, which sorted the colors into a rainbow!
{{comic discussion}}