Coding Class

Learning roadmap← Read the Learn chapter

After reading a concept, solve an exercise, build a program, and fix an error. Each class follows exercise → program project → debugging. Start from requirements and completion criteria before consulting hints.

Roadmap exercises

1. Exercise — choose your path: List the basic chapters from installation through testing. If you can already build a small tool, identify the first advanced chapter. Completion: explain that scope modes begin the advanced path.
2. Build a program — define your first goal: Plan a file word counter, recording input files, expected counts, and a failure case. Completion: one two gives 2, an empty file gives 0, and an absent path gives an error. Implement it in the word-counter class.
3. Debug — locate the failing stage: Classify “command not found,” “type mismatch,” and “runtime index out of bounds” as environment, checking, or execution problems. Choose the first diagnostic action for each. Completion: choose command -v xen, xen check, and xen run respectively, and explain why editing source alone cannot fix command lookup.

Basics · Build a program

Class	Exercise and project focus
Installing Xen	Environment, workspace, PATH
Your first program	Output order, executables, source paths
Variables and values	Value tracing, receipts, mutability
Data types and conversions	Division, averages, numeric mismatches
Functions and control flow	Ranges, even totals, return paths
Strings and collections	Bytes and words, score summaries, empty input
Structs and enums	States, task cards, missing match branches
Missing values and errors	Option, input conversion, ? errors
Working with multiple files	Module paths, shop totals, declarations
Build a word counter	File boundaries, multiple files, arguments
Testing your code	Filters, word-count regression, endpoint bugs

Advanced · Take control

Advanced practice starts with scope modes. Choose how to modify, borrow, transfer, and optimize, and check the resulting restrictions.

Class	Exercise and project focus
Scope modes	Reference scopes, opt experiments, caller annotations
Copies, moves, and references	Independent copies, updates, borrow errors
Generics and type inference	Type arguments, fallbacks, inference errors
Slices and iterators	Pipeline order, box consumption, view lifetimes
Box and recursive data	Link termination, list length, moved owners

Practice workflow

Use a separate file per task. Check and run ordinary programs; use xen test for test-only files. Debugging starters fail intentionally. Record the cause, fix it, and rerun the original and boundary inputs. These are self-checked exercises: use each page’s completion criteria.

Return through Read the Learn chapter when you need a concept. Classes follow the same order as the learning roadmap, so you can alternate between the tabs.