Testing

The following syntaxes work as expected (they create one spoiler tag).

The general rule here is that we allow 0-3 whitespaces before the starting colon, 3 or more colons, any number of optional whitespaces, and the "spoiler" keyword with any non-whitespace character after it.

Normal

spoiler
Hello!

spoiler

Hello!

---

No whitespace

spoiler with no whitespace
Hello!

spoiler with no whitespace

Hello!

---

Leading whitespace

   
title
Hello!

title

Hello!

---

Any number of whitespaces between : and "spoiler"

:::              spoiler title
Hello!
:::

::: spoiler title Hello! :::

---

Any number of whitespaces between "spoiler" and the first non-whitespace character

                title
Hello!

title

Hello!

---

Three or more colons

::::::::::::::::::::::::              spoiler title
Hello!
::::::::::::::::::::::::

:::::::::::::::::::::::: spoiler title Hello! ::::::::::::::::::::::::

---

---

Here's where we run into some weird edge cases:

If there is an ending :::, Lemmy will consume the first instance of ::: only if ::: is on a new line with no other text (and up to 3 white spaces)

a
text (no whitespaces before 
)
:::

a

text (no whitespaces before

) :::

---

a
text (1 whitespaces before 
)
 :::

a

text (1 whitespaces before

) :::

---

a
text (2 whitespaces before 
)
  :::

a

text (2 whitespaces before

) :::

---

a
text (3 whitespaces before 
)
   :::

a

text (3 whitespaces before

) :::

---

a
text (4 whitespaces before 
)
    :::

a

text (4 whitespaces before

) :::

---

---

Lemmy doesn't need an ::: ending in order to display the spoiler. If ::: is not present, it will assume the spoiler continues until the end:

a

 spoiler a
text

---

---

Lemmy will create nested spoilers if it cannot find ::: before another ::: spoiler:

a
text
 spoiler b
more text

a

text

spoiler b more text :::

---

---

The following examples will show the ::: within the spoiler, and will make the spoilers nested

a
text (4 whitespaces before 
)
    :::

a

text (4 whitespaces before

) :::

---

a
text

a

text

---

a
text 

a

text

---

a
text
a

a

text a