More content!

12 files changed, 136 insertions, 3 deletions

diff --git a/lessons/src/lesson007_strings/code.gleam b/lessons/src/lesson007_strings/code.gleam
index c57cf9b..c77163e 100644
--- a/lessons/src/lesson007_strings/code.gleam
+++ b/lessons/src/lesson007_strings/code.gleam
@@ -11,6 +11,9 @@ pub fn main() {
   )
   io.debug("\u{1F600}")
 
+  // String concatenation
+  io.debug("One " <> "Two")
+
   // String functions
   io.debug(string.reverse("1 2 3 4 5"))
   io.debug(string.append("abc", "def"))
diff --git a/lessons/src/lesson007_strings/text.html b/lessons/src/lesson007_strings/text.html
index 21cfc12..820f1b3 100644
--- a/lessons/src/lesson007_strings/text.html
+++ b/lessons/src/lesson007_strings/text.html
@@ -1,8 +1,9 @@
 <p>
-  In Gleam Strings are written as text surrounded by double quotes.
+  In Gleam Strings are written as text surrounded by double quotes, and
+  can span multiple lines and contain unicode characters.
 </p>
 <p>
-  They can span multiple lines and support unicode characters.
+  The <code>&lt;&gt;</code> operator can be used to concatenate strings.
 </p>
 <p>
   Several escape sequences are supported:
@@ -14,7 +15,7 @@
   <li><code>\n</code> - newline</li>
   <li><code>\r</code> - carriage return</li>
   <li><code>\t</code> - tab</li>
-  <li><code>\u{1F600}</code> - unicode codepoint</li>
+  <li><code>\u{xxxxxx}</code> - unicode codepoint</li>
 </ul>
 <p>
   The <a href="https://hexdocs.pm/gleam_stdlib/gleam/string.html"><code>gleam/string</code></a>
diff --git a/lessons/src/lesson008_bools/code.gleam b/lessons/src/lesson008_bools/code.gleam
new file mode 100644
index 0000000..e5c1d98
--- /dev/null
+++ b/lessons/src/lesson008_bools/code.gleam
@@ -0,0 +1,14 @@
+import gleam/io
+import gleam/bool
+
+pub fn main() {
+  // Bool operators
+  io.debug(True && False)
+  io.debug(True && True)
+  io.debug(False || False)
+  io.debug(False || True)
+
+  // Bool functions
+  io.debug(bool.to_string(True))
+  io.debug(bool.to_int(False))
+}
diff --git a/lessons/src/lesson008_bools/text.html b/lessons/src/lesson008_bools/text.html
new file mode 100644
index 0000000..3f60743
--- /dev/null
+++ b/lessons/src/lesson008_bools/text.html
@@ -0,0 +1,17 @@
+<p>
+  A <code>Bool</code> is a either <code>True</code> or <code>False</code>.
+</p>
+<p>
+  The <code>||</code>, <code>&&</code>, and <code>!</code> operators can be used
+  to manipulate bools.
+</p>
+<p>
+  The <code>||</code> and <code>&&</code> operators are short-circuiting,
+  meaning that if the left hand side of the operator is <code>True</code> for
+  <code>||</code> or <code>False</code> for <code>&&</code> then the right hand
+  side of the operator will not be evaluated.
+</p>
+<p>
+  The <a href="https://hexdocs.pm/gleam_stdlib/gleam/bool.html"><code>gleam/bool</code></a>
+  standard library module contains functions for working with bools.
+</p>
diff --git a/lessons/src/lesson009_assignments/code.gleam b/lessons/src/lesson009_assignments/code.gleam
new file mode 100644
index 0000000..a030e43
--- /dev/null
+++ b/lessons/src/lesson009_assignments/code.gleam
@@ -0,0 +1,17 @@
+import gleam/io
+
+pub fn main() {
+  let x = "Original"
+  io.debug(x)
+
+  // Assign `y` to the value of `x`
+  let y = x
+  io.debug(y)
+
+  // Assign `x` to a new value
+  let x = "New"
+  io.debug(x)
+
+  // The `y` still refers to the original value
+  io.debug(y)
+}
diff --git a/lessons/src/lesson009_assignments/text.html b/lessons/src/lesson009_assignments/text.html
new file mode 100644
index 0000000..6d535de
--- /dev/null
+++ b/lessons/src/lesson009_assignments/text.html
@@ -0,0 +1,8 @@
+<p>
+  A value can be assigned to a variable using <code>let</code>.
+</p>
+<p>
+  Variable names can be reused by later let bindings, but the values they
+  reference are immutable, so the values themselves are not changed or mutated
+  in any way.
+</p>
diff --git a/lessons/src/lesson010_discard_patterns/code.gleam b/lessons/src/lesson010_discard_patterns/code.gleam
new file mode 100644
index 0000000..fa2c0e3
--- /dev/null
+++ b/lessons/src/lesson010_discard_patterns/code.gleam
@@ -0,0 +1,4 @@
+pub fn main() {
+  // This variable is never used
+  let _score = 1000
+}
diff --git a/lessons/src/lesson010_discard_patterns/text.html b/lessons/src/lesson010_discard_patterns/text.html
new file mode 100644
index 0000000..46dc79b
--- /dev/null
+++ b/lessons/src/lesson010_discard_patterns/text.html
@@ -0,0 +1,10 @@
+<p>
+  If a variable is assigned but not used then Gleam will emit a warning.
+</p>
+<p>
+  If a variable is intended not to be use then the name can be prefixed with an
+  underscore, silencing the warning.
+</p>
+<p>
+  Try changing the variable name to <code>score</code> to see the warning.
+</p>
diff --git a/lessons/src/lesson011_type_annotations/code.gleam b/lessons/src/lesson011_type_annotations/code.gleam
new file mode 100644
index 0000000..dfba90e
--- /dev/null
+++ b/lessons/src/lesson011_type_annotations/code.gleam
@@ -0,0 +1,12 @@
+import gleam/io
+
+pub fn main() {
+  let name: String = "Gleam"
+  io.debug(name)
+
+  let is_cool: Bool = True
+  io.debug(is_cool)
+
+  let version: Int = 1
+  io.debug(version)
+}
diff --git a/lessons/src/lesson011_type_annotations/text.html b/lessons/src/lesson011_type_annotations/text.html
new file mode 100644
index 0000000..583d7ce
--- /dev/null
+++ b/lessons/src/lesson011_type_annotations/text.html
@@ -0,0 +1,11 @@
+<p>
+  Let assignments can be written with a type annotation after the name.
+</p>
+<p>
+  Type annotations may be useful for documentation purposes, but they do not
+  change how Gleam type checks the code beyond ensuring that the annotation is
+  correct.
+</p>
+<p>
+  Typically Gleam code will not have type annotations for assignments.
+</p>
diff --git a/lessons/src/lesson012_blocks/code.gleam b/lessons/src/lesson012_blocks/code.gleam
new file mode 100644
index 0000000..31e4729
--- /dev/null
+++ b/lessons/src/lesson012_blocks/code.gleam
@@ -0,0 +1,13 @@
+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/lessons/src/lesson012_blocks/text.html b/lessons/src/lesson012_blocks/text.html
new file mode 100644
index 0000000..f943e11
--- /dev/null
+++ b/lessons/src/lesson012_blocks/text.html
@@ -0,0 +1,23 @@
+<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>