Ain't no thang! ...or is it?

Question

Introduction

Street talk can be really difficult to understand, in particular to programmers, who aren't known to be very streetwise.

It is your job to create an interpreter to help us all survive in the urban environment.

Challenge

Given an English sentence as input, create a program or a function that determines whether the outcome of the sentence is positive or negative.

The sentence will contain 0 to 2 negative words. As any programmer knows, a double negative results in a positive. Therefore, your code must output or return a truthy/falsey value according to the following rule:

No negative words  -> truthy
One negative word  -> falsey
Two negative words -> truthy

The list of negative words:

• no, not, none
• Anything ending in n't
• never, neither, nor
• nobody, nothing, nowhere

There is one edge case. Whenever a sentence begins with No,, that word isn't treated as a negative word when determining the result (it does count towards the number of negative words so there can be just one more).

The sentence will follow basic grammar rules (capitalization, punctuation) and will only contain words that can be found from a dictionary (luckily, this doesn't invalidate the question title). The sentence won't contain any proper nouns (sorry, Dr. No, you're out).

Test cases

Truthy:

Yes.
It's noon.
Hello, World!
What is this?
Ain't no thang!
Never say never.
No, it's noon now.
Neither me nor you.
I didn't do nothing!
No, I am your father.
A non-alcoholic drink.
I can't get no satisfaction.
All your base are belong to us.

Falsey:

No.
No, no!
Not today.
Neither am I.
Don't do that!
That's no moon!
And none survived.
Is this not my car?
No man is an island.
Nosebleeds are no fun.
Nothing compares to you.
That's a no, I'm afraid.
No, I am not your mother.

The irony here, of course, is that some of these should be interpreted differently. But hey, you can't fault the speaker for not conforming to our logic.

Rules

Standard loopholes are forbidden. This is code-golf, so be concise!

Answer 1

Retina, 63 bytes

No,

Mi`\bn(e(ith|v)er|o(|body|ne|r|t|thing|where))\b|n't\b
0|2

Try it online!

Explanation

No,

Remove No, from the input. Due to the capitalisation rules, this can only appear at the beginning of the input, so we don't need an explicit ^.

Mi`\bn(e(ith|v)er|o(|body|ne|r|t|thing|where))\b|n't\b

Count the number of matches of the case-insensitive regex after the `. It just matches all the relevant words, where I've extracted common prefixes/suffixes with the alternatives.

0|2

Count 0 or 2s, so we turn even counts into 1 and odd counts into 0.

Answer 2

Bash, 115 107 99 98 97 95 85 bytes

Uses packages Core Utilities (for wc) and grep. Assume the sentence is given via Standard Input. History expansion is disabled by set +o histexpand.

((~`grep -Pio "(?!^no,)\b(no(|t|r|ne|body|thing|where)|ne(v|ith)er|.*n't)\b"|wc -l`%2))

Check the result: In Bash 0 is for true, 1 is for false

How does it work?

((                       )) # Logical evaluation: non-zero to TRUE, zero to FALSE
  ~                    %2   # C-style arithmetic: Bit-Negate and Modulus 2
   $(                 )     # Output of the program chain
     grep -Pio "regex"      # PCRE match, ignore case, output matching part one-per-line
     | wc -l                # Pipe to `wc` and count number of lines

---

18 bytes (115 to 99) saved by inspiration from Qwertiy's answer and Martin Ender's answer. 1 byte thanks to Nahuel Fouilleul.

Answer 3

Javascript ES6, 89 87 86 chars

s=>s.match(/(?!^no,)\bn(o(|t|r|ne|body|thing|where)|e(v|ith)er)\b|n't\b|$/ig).length&1

Test:

f=s=>s.match(/(?!^no,)\bn(o(|t|r|ne|body|thing|where)|e(v|ith)er)\b|n't\b|$/ig).length&1

console.log(`Yes.
It's noon.
Hello, World!
Never say never.
Ain't no thang!
No, it's noon now.
Neither me nor you.
I didn't do nothing!
No, I am your father.
A non-alcoholic drink.
I can't get no satisfaction.
All your base are belong to us.`.split`
`.every(f))

console.log(`No.
No, no!
Not today.
Neither am I.
Don't do that!
That's no moon!
And none survived.
No man is an island.
Nosebleeds are no fun.
Nothing compares to you.
That's a no, I'm afraid.
No, I am not your mother.`.split`
`.every(s=>!f(s)))

Answer 4

Perl 5, 74 bytes

73 bytes code + 1 for -p.

s/No,//;$_=!(s/(\bn(o(r|t|ne|body|thing|where)?|e(v|ith)er)|n't)\b//gi%2)

Try it online!