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Required fields*

Rev

Required fields*

Turn a string into a snake

Write a function or program which writes an input string out as a snake.

The snake starts heading to the right. If a / or \ character is reached in the input, the snake changes direction as if the character represented a wall placed diagonally across the path.

That is it changes direction as follows (before -> after):

/: right -> up; up -> right; left -> down; down -> left
\: right -> down; down -> right; left -> up; up -> left

Every character other than / or \ is output literally.

So given the input sn/ak\e the output is:

ek 
 a
sn

If the snake crosses its own path, the later characters replace earlier ones:

boa/co\ns/t\rictor

sno
trictor
boa

Input

A string of characters from the set [-a-zA-Z_/\]. There may be consecutive direction change characters (/ and \) including of the same type (////). The first character may be a direction change character. There will be at least one non-direction-change character.

Output

Multiple lines of output as described above, in any reasonable format. Extra whitespace is not allowed:

Each line must contain the minimal amount of left-padding such that (at least) one line has zero left padding.
There should be either no right-padding, or the minimal amount to produce lines of equal length.
No extra blank lines are allowed at the start or end. The final new line character is optional.

Scoring

This is code golf. Standard rules apply.

Sample output

/\backwards

sdrawkcab

_oo/o/oOoo\o\oo/O/_

 ooOoo O_
_oo ooo

TigeR\attlE\gg-eateR/ibboN/ose-horneD\warf-beakeD/esertWomA\nacondA\ddeR/aceR/aT\aipan

TigeR Nose-horneD
 a o w
 t b a
 t n b r
 l a ReddA f
 EggpeateRd -
 i c n b
 a e o e
 TaR c a
 a k
 n e
 AmoWtreseD

\Mamba/Nu\mberF\ive

eviF
 r M
 e a
 b m
 m b
 uNa

There/\and\/back

Tdback

Answer*

# [05AB1E](https://github.com/Adriandmen/05AB1E/wiki/Commands), <s>30</s> 27 [bytes](https://github.com/Adriandmen/05AB1E/wiki/Codepage)

 εY…/ \yk©di®>·^Võëˆ]Jā≠>s¯Λ

-3 bytes thanks to *@Neil*.

[Try it online.](https://tio.run/##yy9OTMpM/f//3NbIRw3L9BViKrMPrUzJPLTO7tD2uLDDWw@vPt0W63Wk8VHnArviQ@vPzf7/PyQzPTUoJrGkJCfVNSY9XTc1sSQ1SD8zKSnfTz@/OFU3I78oL9UlpjyxKE03KTUxO9VFP7U4tagkPD/XMSYvMTk/L8UxJiUFqCcxGUSExCRmFiTm/dfVzcvXzUmsqgQA) (No test suite with all test cases at once, because the `.Λ` will overlap previous drawings and there isn't a way to reset it.)

**Explanation:**



 ε # Map over each character `y` of the (implicit) input:
 # (implicitly push the current character `y`)
 Y # Push variable `Y` (which starts at 2)
 …/ \yk # Get the (0-based) index of character `y` in "/ \",
 # or -1 if it's not present in this string
 © # Store this index in variable `®` (without popping)
 di # Pop and if this index is non-negative (aka `y` is "/" or "\"):
 ® # Push index `®` (0 for "/" or 2 for "\")
 > # Increase it by 1 (1 for "/" or 3 for "\")
 · # Double it (2 for "/" or 6 for "\")
 ^ # Bitwise-XOR Y by this
 V # Pop and store this value as new `Y`
 õ # Push an empty string ""
 ë # Else (aka `y` is a letter, "_", or "-"):
 ˆ # Pop and add the current `Y` to the global array
 ] # Close both the outer if-else statement and map
 J # Join the characters (and empty strings) together,
 # which will be the input-string without the "\" and "/"
 ā # Push a list in the range [1,length] (without popping)
 ≠ # Check for each integer that it's NOT 1: [0,1,1,1,...]
 > # Increase each by 1: [1,2,2,2,...]
 s # Swap so the string is at the top of the stack again
 ¯ # Push the global array
 Λ # Use the Canvas builtin with these three arguments
 # (after which the result is implicitly output immediately)

*Additional explanation of the Canvas builtin `Λ`/`.Λ`*:

It takes 3 arguments to draw an ASCII shape:

1. Length of the lines we want to draw
2. Character/string to draw
3. The direction to draw in, where each digit represents a certain direction:



 7 0 1
 ↖ ↑ ↗
 6 ← X → 2
 ↙ ↓ ↘
 5 4 3

`εY…/ \yk©di®>·^Võëˆ]Jā≠>s¯` with example input `boa/co\ns/t\rictor` creates the following three Canvas arguments:

1. Lengths: &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;`[1,2,2,2,2,2,2,2,2,2,2,2,2,2]`
2. Chars to draw: `[b,o,a,c,o,n,s,t,r,i,c,t,o,r]`
3. Directions: &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;`[2,2,2,0,0,6,6,4,2,2,2,2,2,2]`

So it'll draw `b` of length 1 in direction `2`/→:

 b

Then `o` of length 2-1 still in direction `2`/→:

 bo

Likewise for `a`:

 boa

Then for `c` it changes direction to `0`/↑:

 c
 boa

Then `o` of length 2-1 still in direction `0`/↑:

 o
 c
 boa

Then for `n` it changes directions again, this time to `6`/←:

 no
 c
 boa

Etc.

[See this 05AB1E tip of mine to learn more about the Canvas builtin.](https://codegolf.stackexchange.com/a/175520/52210)

As for how I change directions based on the `/` or `\`:

- For `/` I do a bitwise-XOR with 2, changing the directions as: 0⇒2; 2⇒0; 4⇒6; 6⇒4 - [try it online](https://tio.run/##yy9OTMpM/f/fKO7//2gDHSMdEx2zWAA);
- For `\` I do a bitwise-XOR with 6, changing the directions as: 0⇒6; 2⇒4; 4⇒2; 6⇒0 - [try it online](https://tio.run/##yy9OTMpM/f/fLO7//2gDHSMdEx2zWAA);
- For letters, `-`, or `_`, the direction remains the same.

If this is an answer to a challenge…

…Be sure to follow the challenge specification. However, please refrain from exploiting obvious loopholes. Answers abusing any of the standard loopholes are considered invalid. If you think a specification is unclear or underspecified, comment on the question instead.
…Try to optimize your score. For instance, answers to code-golf challenges should attempt to be as short as possible. You can always include a readable version of the code in addition to the competitive one. Explanations of your answer make it more interesting to read and are very much encouraged.
…Include a short header which indicates the language(s) of your code and its score, as defined by the challenge.

More generally…

…Please make sure to answer the question and provide sufficient detail.
…Avoid asking for help, clarification or responding to other answers (use comments instead).

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1

\$\begingroup\$ 28 bytes: εY"//\"yk©di®>·^Võëˆ]Jā≠>s¯Λ. \$\endgroup\$

Neil
– Neil

2025年04月11日 09:34:10 +00:00
Commented Apr 11 at 9:34
\$\begingroup\$ @Neil Thanks! The "//\" can be ...//\ for an additional -1. :) \$\endgroup\$

Kevin Cruijssen
– Kevin Cruijssen

2025年04月11日 14:40:07 +00:00
Commented Apr 11 at 14:40
\$\begingroup\$ What with compressed strings I I didn't feel like checking to see what the most efficient way of coding the string was... \$\endgroup\$

Neil
– Neil

2025年04月11日 15:34:33 +00:00
Commented Apr 11 at 15:34

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