Style-Guide.md

@@ -1 +1,79 @@
-Test style guide, please ignore.
+## Languages Used
+
+All game code is written to target C# 8.0. Auxiliary tools are written to target Python 3 or unix shell.
+
+## C# Style Guide
+
+The C# style guide is largely based on the [Google Java Style Guide](https://google.github.io/styleguide/javaguide.html). Unless specified otherwise, do what the Google Java style guide recommends. Differences, or particular points worth additional note, are listed in the sections below.
+
+
+### Whitespace characters
+
+Spaces only. No tabs. Manually indenting things to make things line up nicely is fine.
+
+### Braces & blocks
+
+Each new block is indented by two spaces.
+
+We follow Google-style (K&R) brace & block structure, like this:
+```csharp
+if (foo) {
+  bar;
+} else {
+  blah;
+}
+```
+
+rather than the more-common C# style which looks something like this:
+```csharp
+if (foo)
+{
+  bar;
+}
+else
+{
+  blah;
+}
+```
+
+Braces are always used where optional, such as single-line if/while statements.
+
+### Line Length
+
+Maximum line length is 100 characters. Exception: `Levels.cs` (and similar files that are closer to *data* than *code*) can have lines of any length.
+
+If a line is too long, prefer to line-wrap it at a higher syntactic level (as the Google Java guide suggests). When a line is broken at an operator, put the line-break *after* the operator (which is the opposite of what the Google Java guide suggests.)
+
+Continuation lines should be indented by at least 4 spaces.
+
+Example:
+```csharp
+if (LongMethodName() && reasonablyLengthyLocalVariable &&
+    SomeOtherThing() {
+  DoSomething();
+}
+```
+
+### Names
+
+Methods & functions are named with an initial capital letter, as is common in other C# code (`DoSomething()`, not `doSomething()`). So are public fields of classes and structs (including properties).
+
+We generally follow Google's rules for treating acronyms as though they are a single word with only an initial capital letter (`FpsCounter`, not `FPSCounter`), with the exception that if a name is *entirely* an acronym, it stays entirely in uppercase (`AABB`, not `Aabb`). Once it's incorporated into a longer identifier by smooshing it together with some other word, it loses the all-caps treatment (`AabbList`, not `AABBList`).
+
+Words in identifier names should be written out in full, with the following explicit exceptions which may be abbreviated:
+* `pos` instead of `position`
+* `rect` instead of `rectangle`
+
+### Namespaces
+
+All code is in `namespace SemiColinGames`. There are no sub-namespaces, with the exception of test code, which goes in `namespace SemiColinGames.Tests`.
+
+### Source files & class names
+
+Unlike in Java, source files in C# need not contain only a single top-level class. It is fine to group multiple closely-related classes or structs into a single file, if it makes sense to do so.
+
+If a file contains only a single class, the filename should match the name of that class.
+
+### Extension Methods
+
+All definitions of extension methods must be in the file `ExtensionMethods.cs`.