Interpreters
Crafting Interpreters study plan, and how long it takes
Crafting Interpreters takes about 160 hours if you type every line and do some of the challenges: roughly 57 hours for jlox and 100 for clox in our chapter guides. Next to two NeetCode problems a week, at about 8 to 10 hours a week in all, that is 28 weeks. Here is the plan: a chapter a week, the three short opening chapters together.
The 28 weeks
| Week | Chapters | What you build |
|---|---|---|
| 1 | 1 to 3 | Read: the map of the territory and the Lox language |
| 2 | 4 | jlox scanner |
| 3 | 5 | AST generator |
| 4 | 6 | Recursive descent parser |
| 5 | 7 | Evaluator |
| 6 | 8 | Statements and environments |
| 7 | 9 | Control flow |
| 8 | 10 | Functions and closures |
| 9 | 11 | Resolver |
| 10 | 12 | Classes |
| 11 | 13 | Inheritance: jlox done |
| 12 | 14 | clox: chunks of bytecode |
| 13 | 15 | The VM |
| 14 | 16 | Scanner on demand |
| 15 | 17 | Pratt parser compiler |
| 16 | 18 | Value types |
| 17 | 19 | Strings |
| 18 | 20 | Hash table |
| 19 | 21 | Globals |
| 20 | 22 | Locals |
| 21 | 23 | Jumps |
| 22 | 24 | Calls and functions |
| 23 | 25 | Closures and upvalues |
| 24 | 26 | Garbage collection |
| 25 | 27 | Classes and instances |
| 26 | 28 | Methods and initializers |
| 27 | 29 | Superclasses |
| 28 | 30 | Optimization: clox done |
Every chapter has its own reading guide with a time budget, the challenges worth doing, common traps and the test suite that checks it.
Where people get stuck
- Chapter 6 (parsing): precedence and error recovery are new to most people. Draw the grammar.
- Chapter 11 (resolving): the bug it fixes is subtle. Write the failing closure example first.
- Chapter 17 (compiling expressions): the Pratt parser is a different way of thinking about precedence.
- Chapter 25 (closures): upvalues are the hardest idea in the book. Budget extra.
- Chapter 26 (garbage collection): bugs appear far from their cause. Turn on the stress-test mode.
Faster or slower
People who already know Java and C and skip the challenges report finishing in well under 160 hours; people learning C as they go often take longer for clox. If that is still too much, half pace gives each week two calendar weeks; if you have more time, nothing stops you from working ahead of the calendar. The plan generator gives you real dates for either pace.
Keep yourself honest
Each coding chapter has a test suite in the book's repository. On cracked.guide, you push your repo and a GitHub Actions workflow runs the official tests; a passing chapter is marked verified. See the Lox test suite and how the verification works.
Questions
How long does Crafting Interpreters take?
About 160 hours typing the code and doing some challenges. The cracked.guide path gives it 28 weeks, a chapter a week next to two NeetCode problems.
Can I do Crafting Interpreters in a month?
Full time, yes. Part time, most people need three to four months to type it all and understand it.
Should I do the challenges?
Some of them. They are where you design rather than follow. Do them on a branch so the official tests still pass on main.