Improve introduction of modules and imports

Thanks @RyanBrewer317!

2 files changed, 36 insertions, 0 deletions

diff --git a/src/content/chapter0_basics/lesson15_blocks/code.gleam b/src/content/chapter0_basics/lesson15_blocks/code.gleam
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+++ b/src/content/chapter0_basics/lesson15_blocks/code.gleam
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+import gleam/io
+
+pub fn main() {
+  let fahrenheit = {
+    let degrees = 64
+    degrees
+  }
+  // io.debug(degrees) // <- This will not compile
+
+  // Changing order of evaluation
+  let celsius = { fahrenheit - 32 } * 5 / 9
+  io.debug(celsius)
+}
diff --git a/src/content/chapter0_basics/lesson15_blocks/en.html b/src/content/chapter0_basics/lesson15_blocks/en.html
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+++ b/src/content/chapter0_basics/lesson15_blocks/en.html
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+<p>
+  Blocks are one or more expressions grouped together with curly braces. Each
+  expression is evaluated in order and the value of the last expression is
+  returned.
+</p>
+<p>
+  Any variables assigned within the block can only be used within the block.
+</p>
+<p>
+  Try uncommenting <code>io.debug(degrees)</code> to see the compile error from
+  trying to use a variable that is not in scope.
+</p>
+<p>
+  Blocks can also be used to change the order of evaluation of binary operators
+  expressions. 
+</p>
+<p>
+ <code>*</code> binds more tightly than <code>+</code> so the expression
+ <code>1 + 2 * 3</code> evaluates to 7. If the <code>1 + 2</code> should be
+ evaluated first to make the expression evaluate to 9 then the expression can be
+ wrapped in a block: <code>{ 1 + 2 } * 3</code>. This is similar to grouping
+ with parentheses in some other languages.
+</p>