From 7eb172ce6316940e708527bc16e425048f80c0d4 Mon Sep 17 00:00:00 2001
From: JalonSolov <JalonSolov@gmail.com>
Date: Mon, 5 Feb 2024 23:31:31 -0500
Subject: [PATCH] expand first 2 lessons and add 3rd

---
 lessons/1.what-is-v.md                 |  9 +++-
 lessons/2.writing-our-first-program.md | 39 ++++++++++++++-
 lessons/3.next-level-program.md        | 67 ++++++++++++++++++++++++++
 3 files changed, 113 insertions(+), 2 deletions(-)
 create mode 100644 lessons/3.next-level-program.md

diff --git a/lessons/1.what-is-v.md b/lessons/1.what-is-v.md
index 4df4af8..2f014e5 100644
--- a/lessons/1.what-is-v.md
+++ b/lessons/1.what-is-v.md
@@ -5,4 +5,11 @@ V is a [general purpose programming language](https://en.wikipedia.org/wiki/Gene
 This means it can be used to create any type of program you desire, rather than being focused on
 any one particular type of program.
 
-You can install it by [following the instructions here](https://github.com/vlang/v/blob/master/README.md#installing-v-from-source).
+V is also a statically typed, compiled langauge.  Statically typed means that
+all variable types are known at compile time, and cannot change type at runtime.
+
+In other words, if you create a string variable, it will always be a string
+variable, and cannot be changed to an integer without changing the source and
+recompiling your program.
+
+You can install V by [following the instructions here](https://github.com/vlang/v/blob/master/README.md#installing-v-from-source).
diff --git a/lessons/2.writing-our-first-program.md b/lessons/2.writing-our-first-program.md
index 4a4c26c..03da320 100644
--- a/lessons/2.writing-our-first-program.md
+++ b/lessons/2.writing-our-first-program.md
@@ -3,8 +3,45 @@ Writing Our First Program
 
 In this lesson, we'll examine one of the simplest programs in V.
 
+Yes it is the iconic [Hello World](https://en.wikipedia.org/wiki/%22Hello%2C_World!%22_program)
+that is often the first program someone would write in language they are learning.
+
 ```v
 fn main() {
-	println('hello world')
+	println('Hello, World!')
 }
 ```
+
+In V, functions are declared with the `fn` keyword, followed by the name of the
+function (in this case `main`), the parameters to the function, if any (in this
+case there aren't any), then an opening curly brace, `{`, on the same line.
+
+V also has 2 ways to output text - one that only prints what is given to it,
+`print`, and one that automatically adds a linefeed to the end of whatever it
+is given, `println`.
+
+Using
+```v
+	println('Hello, World!)`
+```
+above is the equivalent to
+```c
+	printf("Hello, World!\n");
+```
+in C.
+
+Finally, the closing curly brace, `}`, to end the function.
+
+One thing to clarify - V doesn't care if you use single quotes (`'`) or double
+quotes (`"`) around a string of characters, the opening and closing quotes just
+have to match.  This means you can't use `'a string"` or `"a string'` but either
+`'a string'` or `"a string"` are fine.
+
+This is unusual amongst programming programming languages, where you must only
+use one or the other (in C, for example, only double quotes are valid around
+strings), or if both types are supported, they have different meanings.  In V,
+they are both equally valid, and mean exactly the same thing.
+
+Also note that both `print` and `println` are builtin functions in V - nothing extra
+is needed to use them, other than typing their names and giving them something
+to print.
diff --git a/lessons/3.next-level-program.md b/lessons/3.next-level-program.md
new file mode 100644
index 0000000..4168851
--- /dev/null
+++ b/lessons/3.next-level-program.md
@@ -0,0 +1,67 @@
+Next Level Program
+==================
+
+Now, for a slightly more complex version of the `Hello World` program.  This is
+a copy of one of the examples on the [V Home Page](https://vlang.io).
+```v
+fn main() {
+    areas := ['game', 'web', 'tools', 'science', 'systems',
+              'embedded', 'drivers', 'GUI', 'mobile']
+    for area in areas {
+        println('Hello, ${area} developers!')
+    }
+}
+```
+
+In this version of the program, several more ideas are introduced.
+
+V variables are declared by giving the name, followed by `:=` then a value to
+set both the initial value of the variable, as well as it's type.
+
+In the example,
+```v
+    areas := ['game', 'web', 'tools', 'science', 'systems',
+              'embedded', 'drivers', 'GUI', 'mobile']
+```
+`areas` is declared as the name of a variable, and is assigned the type `[]string`
+(meaning an array of strings), with the initial values of the array set to the
+strings inside the `[]` characters.
+
+Unlike other languages, V does not allow you to create a variable without
+assigning a value, as the value sets the variable type.
+
+The 2nd new thing is the [`for`](https://github.com/vlang/v/blob/master/doc/docs.md#for-loop)
+loop, which is the only looping statement in V.
+
+For this variation, it is used to loop over the values in the `areas` array, so
+that each one can be used in the `println` statement.
+```v-ignore
+    for area in areas {
+```
+This means "for every string in the `areas` string array, assign the value to a
+variable named `area`, then execute the statements inside the `{}`.
+
+The `println` statement is also different in this example:
+```v
+        println('Hello, ${area} developers!')
+```
+Here, V uses a new concept called "string interpolation".  This basically means
+that V will take whatever is inside `${}` in the string, treat it as V code,
+and use the value as if it was part of the string when it is printed.
+
+For this specific case, it means "use the value of the variable named `area`",
+and the result is a string that changes every time through the loop, as the
+value of `area` changes.
+
+The output from running this program is
+```
+Hello, game developers!
+Hello, web developers!
+Hello, tools developers!
+Hello, science developers!
+Hello, systems developers!
+Hello, embedded developers!
+Hello, drivers developers!
+Hello, GUI developers!
+Hello, mobile developers!
+```