diff options
Diffstat (limited to 'lessons/src/lesson035_nil')
| -rw-r--r-- | lessons/src/lesson035_nil/code.gleam | 11 | ||||
| -rw-r--r-- | lessons/src/lesson035_nil/text.html | 15 |
2 files changed, 26 insertions, 0 deletions
diff --git a/lessons/src/lesson035_nil/code.gleam b/lessons/src/lesson035_nil/code.gleam new file mode 100644 index 0000000..c28080b --- /dev/null +++ b/lessons/src/lesson035_nil/code.gleam @@ -0,0 +1,11 @@ +import gleam/io + +pub fn main() { + let x = Nil + io.debug(x) + + // let y: List(String) = Nil + + let result = io.println("Hello!") + io.debug(result == Nil) +} diff --git a/lessons/src/lesson035_nil/text.html b/lessons/src/lesson035_nil/text.html new file mode 100644 index 0000000..3416643 --- /dev/null +++ b/lessons/src/lesson035_nil/text.html @@ -0,0 +1,15 @@ +<p> + <code>Nil</code> is Gleam's unit type. It is a value that is returned by + functions that have nothing else to return, as all functions much return + something. +</p> +<p> + <code>Nil</code> is not a valid value of any other types, that is values in + Gleam are not nullable. If the type of a value is <code>Nil</code> then it is + the value <code>nil</code>. If it is some other type then the value is not + <code>Nil</code>. +</p> +<p> + Uncomment the line that assigns <code>Nil</code> to a variable with an + incompatible type annotation to see the comile time error it produces. +</p> |