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authorLouis Pilfold <louis@lpil.uk>2024-01-18 20:34:43 +0000
committerLouis Pilfold <louis@lpil.uk>2024-01-18 20:34:43 +0000
commitab2b9a982ede817362072623ff9ae2aa42e083da (patch)
tree5c055c588fafc5075831b7d9273e232da76da73b /src/content/chapter2_flow_control/lesson09_alternative_patterns
parent8d93f5ab2a04a9f2f8eb23b11617d83fad1c5316 (diff)
downloadtour-ab2b9a982ede817362072623ff9ae2aa42e083da.tar.gz
tour-ab2b9a982ede817362072623ff9ae2aa42e083da.zip
Move recursion lessons together
Diffstat (limited to 'src/content/chapter2_flow_control/lesson09_alternative_patterns')
-rw-r--r--src/content/chapter2_flow_control/lesson09_alternative_patterns/code.gleam14
-rw-r--r--src/content/chapter2_flow_control/lesson09_alternative_patterns/text.html17
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diff --git a/src/content/chapter2_flow_control/lesson09_alternative_patterns/code.gleam b/src/content/chapter2_flow_control/lesson09_alternative_patterns/code.gleam
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+++ b/src/content/chapter2_flow_control/lesson09_alternative_patterns/code.gleam
@@ -0,0 +1,14 @@
+import gleam/io
+import gleam/int
+
+pub fn main() {
+ let number = int.random(10)
+ io.debug(number)
+
+ let result = case number {
+ 2 | 4 | 6 | 8 -> "This is an even number"
+ 1 | 3 | 5 | 7 -> "This is an odd number"
+ _ -> "I'm not sure"
+ }
+ io.debug(result)
+}
diff --git a/src/content/chapter2_flow_control/lesson09_alternative_patterns/text.html b/src/content/chapter2_flow_control/lesson09_alternative_patterns/text.html
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+<p>
+ Alternative patterns can be given for a case clause using the
+ <code>|</code> operator. If any of the patterns match then the clause matches.
+</p>
+<p>
+ When matching on multiple subjects there must be the same number of patterns
+ as there are subjects. Try removing one of the <code>_,</code> sub-patterns to
+ see the compile time error that is returned.
+</p>
+<p>
+ If a pattern defines a variable then all of the alternative patterns for that
+ clause must also define a variable with the same name and same type.
+</p>
+<p>
+ Currently it is not possible to have nested alternative patterns, so the
+ pattern <code>[1 | 2 | 3]</code> is not valid.
+</p>