Validate 2Col syntax!

Question

As a couple of people may have noticed lately, I've largely abandoned development of Braingolf because it's boring and uninspired, and moved on to 2Col which is a little more interesting, and not designed to be a golfing language.

The defining feature of 2Col is that every line of code must be exactly 2 characters long, excluding the newline. This means that the length of a 2Col program can always be calculated as 3n-1 where n is the number of lines in the program.

So here's my challenge: Given 2Col code as a string, output truthy if it is valid 2Col code (Every line is exactly 2 characters and it conforms with the 3n-1 formula), and falsey otherwise.

Input

Input should be taken as a single string, or an array of characters.

Output

A truthy value if the input string is valid layout, and a falsey value otherwise.

Your code should be consistent in which truthy/falsey values it uses

Testcases

======
F!
$^
----
truthy
======


======
*8
+1
Sq
----
truthy
======


======
nop
xt
----
falsey
======


======
+1
+1
#^

----
falsey
======


======
<empty string>
----
falsey
======


======
ye
----
truthy
======


======
no<space>
----
falsey
======


======
test
----
falsey
======


======
puzzle
----
falsey
======

Scoring

This is code-golf so fewest bytes wins!

Answer 1

Brachylog (2), 4 bytes

ṇl₂ᵐ

Try it online!

Full program (because this is a decision-problem; Brachylog full programs output false. if there was an assertion failure, true. without one).

Explanation

ṇl₂ᵐ
ṇ     Split input into lines
   ᵐ  For each line:
 l₂     Assert that that line has length 2

Subscripts on l are one of Brachylog's newest features (although still older than the challenge), and this is a good challenge to use them on.

Answer 2

JavaScript (ES6), 24 28 25 24 bytes

Fixed program and shaved of three bytes thanks to @PunPun1000

Shaved off one byte thanks to @Shaggy

s=>/^(..\n)*..$/.test(s)

Returns true if valid and false if not.

f=
s=>/^(..\n)*..$/.test(s)

t=
`22
22
22
22
22`

console.log(f(t));
console.log(f(t.slice(0, -1)));

Answer 3

Haskell, 23 52 32 bytes

all((==2).length).lines.(++"\n")

I got my inspiration from some other solutions, clever trick adding that "\n".

Answer 4

Cubix, 20 bytes

Returns 1 for truthy and nothing for falsey

@1OuABq>;;?w-!$@;U_N

Cubified

    @ 1
    O u
A B q > ; ; ? w
- ! $ @ ; U _ N
    . .
    . .

• ABq slurp in all the input, reverse it and push the EOI(-1) to the bottom of the stack
• >;; Step into the loop and remove items from the stack
• ? Test for EOI(-1).
  • If found 1uO@ push 1 to the stack, u-turn onto integer output and halt
  • Otherwise _ reflect back onto the ? which redirects to the w lane shift
• N-!$@;U push line feed (10) onto the stack, subtract, test result, skip the halt if false, remove the result and u-turn
• ;;> remove the line feeds from the stack and redirect into the loop.

Try it online!

Answer 5

Python, 51

lambda s:all(len(l)==2for l in(s+"\n").splitlines())

Test case runner:

tcs = {
    "F!\n$^": 1,
    "*8\n+1\nSq": 1,
    "nop\nxt": 0,
    "+1\n+1\n#^\n": 0,
    "": 0,
    "ye": 1,
    "no ": 0,
    "test": 0,
    "puzzle": 0
}
f = lambda s:all(len(l)==2for l in(s+"\n").splitlines())
for tc, expected in tcs.items():
    assert f(tc) == expected

Answer 6

JavaScript (ES6), 35 24 bytes

s=>!/^.?$|.../gm.test(s)

---

Try it

f=
s=>!/^.?$|.../gm.test(s)
oninput=_=>o.innerText=f(i.value)
o.innerText=f(i.value=`F!
$^`)

<textarea id=i></textarea><pre id=o>

Answer 7

Jelly, 6 bytes

ỴL€=2Ṃ

Try it online!

Explanation:

ỴL€=2Ṃ
Ỵ       Split at newlines
 L€     Length of each...
   =2   ...equals two.
     Ṃ  Minimum.

Answer 8

Retina, 10 bytes

^..(¶..)*$

Try it online! Outputs 1 or 0 as appropriate.

Answer 9

J-uby, 19 18 bytes

:=~&/^(..\n*)..$/m

:=~& makes an anonymous function that takes x and returns 0 if it matches the regex /^(..\n*)..$/m, or nil otherwise.

Answer 10

05AB1E, 6 bytes

¶¡D2ùQ

Try it online!

¶¡D2ùQ   Argument s
¶¡       Split s on newlines
  D      Duplicate
   2ù    Keep only elements of length 2
     Q   Compare

Answer 11

Japt, 7 6 bytes

·eÈʶ2

Try it online

---

Explanation

     :Implicit input of string "U"
·    :Split to array on newline
eÈ   :Maps over the array, checking that every item's ...
Ê    :length ...
¶2   :Equals 2
     :Implicit output of result

Answer 12

Java (OpenJDK 8), 25 bytes

s->s.matches("(..\n)*..")

Try it online!

Checks if the input string has any number of lines followed by a line feed and a final line without one (ensures at least one line)

Answer 13

Bash + GNU utilities, 13

grep -qv ^..$

This sets the shell return value (accessible in $?) to 0 for false and 1 for true. This is actually the opposite sense compared to normal shell convention, so to make that right you'd need to do:

Bash + GNU utilities, 15

! grep -qv ^..$

Answer 14

Ruby, 22 bytes

->s{s=~/^(..\n*)..$/m}