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Diffstat (limited to 'src/content/chapter1_functions/lesson08_labelled_arguments')
-rw-r--r-- | src/content/chapter1_functions/lesson08_labelled_arguments/code.gleam | 16 | ||||
-rw-r--r-- | src/content/chapter1_functions/lesson08_labelled_arguments/text.html | 23 |
2 files changed, 39 insertions, 0 deletions
diff --git a/src/content/chapter1_functions/lesson08_labelled_arguments/code.gleam b/src/content/chapter1_functions/lesson08_labelled_arguments/code.gleam new file mode 100644 index 0000000..25bb8c1 --- /dev/null +++ b/src/content/chapter1_functions/lesson08_labelled_arguments/code.gleam @@ -0,0 +1,16 @@ +import gleam/io + +pub fn main() { + // Without using labels + io.debug(calculate(1, 2, 3)) + + // Using the labels + io.debug(calculate(1, add: 2, multiply: 3)) + + // Using the labels in a different order + io.debug(calculate(1, multiply: 3, add: 2)) +} + +fn calculate(value: Int, add addend: Int, multiply multiplier: Int) { + value * multiplier + addend +} diff --git a/src/content/chapter1_functions/lesson08_labelled_arguments/text.html b/src/content/chapter1_functions/lesson08_labelled_arguments/text.html new file mode 100644 index 0000000..b1d771c --- /dev/null +++ b/src/content/chapter1_functions/lesson08_labelled_arguments/text.html @@ -0,0 +1,23 @@ +<p> + When functions take several arguments it can be difficult to remember what the + arguments are, and what order they are expected in. +</p> +<p> + To help with this Gleam supports labelled arguments, where function arguments + are given an external label in addition to their internal name. These labels + are written before the argument name in the function definition. +</p> +<p> + When labelled arguments are used the order of the arguments does not matter, + but all unlabelled arguments must come before labelled arguments. +</p> +<p> + There is no performance cost to using labelled arguments, it does not allocate + a dictionary or perform any other runtime work. +</p> +<p> + Labels are optional when calling a function, it is up to the programmer to + decide what is clearest in their code. +</p> + + |