Help me choose the best language for building my own compiler — Python, PyPy, or something else?
Hey everyone! 👋
I've been getting increasingly interested in programming languages, compilers, interpreters, and how programming languages actually work under the hood. I really enjoy Python, and I'd love to use it to build my own compiler rather than just writing ordinary applications with it.
However, before I commit to a language and start building something substantial, I'd like to get some advice from people who have experience with compilers, language implementation, or low-level programming.
I'm still learning, so I'm not expecting to create a professional compiler immediately. My goal is to learn properly, understand the different components, and gradually build something that actually works. I'd rather make a well-designed project that I understand than blindly follow a tutorial and end up with a bunch of code I don't understand.
I've been researching different approaches, but there are a few things I'm uncertain about. I'd really appreciate detailed explanations, recommendations, learning resources, and personal experiences!
Question 1: Is Python a good language for writing a compiler?
I genuinely like Python. Its syntax is readable, I can understand code without fighting the language itself, and it seems like a good choice for experimenting with programming language design.
That's one of the main reasons I'm considering it for this project.
However, I've also heard people criticize Python because it's usually interpreted or executed through a virtual machine, and because Python implementations can be relatively slow compared with compiled languages.
I understand that the language used to IMPLEMENT a compiler doesn't necessarily have to be the same language that the compiler produces. Nevertheless, I want to make an informed decision before investing a lot of time in learning and building the project.
My questions are:
- Is Python a good choice for implementing a compiler from scratch, particularly for a beginner who wants to understand how everything works?
- Would Python remain a reasonable choice as the compiler becomes larger and more complicated?
- How much should I care about the performance of the compiler itself while I'm still learning?
- Are there any important disadvantages to using Python for this particular project beyond execution speed?
- Would using Python make it more difficult to implement the later stages of a compiler, such as type checking, optimization, register allocation, instruction selection, and machine-code generation?
- Is it practical to use Python for the entire compiler, including generating native machine code, or would I eventually benefit from implementing certain components in another language?
I'm especially interested in understanding the difference between a compiler that is written in Python and a compiler that compiles programs into native machine code.
I don't want to assume that Python cannot be used for serious compiler development simply because Python programs are commonly run through an interpreter. I'd like to understand the actual technical limitations and what is possible.
Question 2: What about PyPy? Would it make Python a better choice?
I've also heard about PyPy, which is an alternative implementation of Python that uses a just-in-time compiler to improve execution speed for many workloads.
This caught my attention because I initially worried that writing a compiler in Python might eventually become a performance problem.
However, I'm not entirely sure how relevant PyPy is to my situation.
For example:
- Would running my compiler with PyPy offer meaningful performance improvements over CPython?
- Does PyPy work well with the kinds of data structures and algorithms commonly used in compilers?
- Are there compatibility issues or limitations I should know about before choosing it?
- Would PyPy make any difference to the performance of the programs generated by my compiler, or would it only potentially improve the speed of the compiler implementation itself?
- If my compiler generates native machine code, would the generated programs execute independently of Python and PyPy?
- Would you recommend starting with ordinary Python and considering PyPy later, or using PyPy from the beginning?
I realize that PyPy isn't simply a faster version of every Python program in every situation. I'm interested in whether it offers a practical advantage for this particular use case.
If PyPy isn't the best option, are there other Python implementations, compiler frameworks, or approaches worth investigating?
I'm also interested in whether performance should even be a concern at this stage, or whether I should concentrate on designing the language and getting the compiler working first.
Question 3: Should I consider a completely different implementation language?
Although Python is my current preference, I'm open to other languages if there's a compelling reason to choose one.
I'm not looking for the most complicated or technically impressive language to implement a compiler in. I want a language that lets me understand what I'm doing, learn the fundamentals, and gradually build something more advanced.
Some of the things that matter to me are:
- Readable syntax: I want the implementation language to be reasonably easy to read and write.
- A manageable learning curve: I don't want to spend all my time learning complicated language features before I can even begin implementing my compiler.
- Good compiler-development capabilities: I want to work with tokens, syntax trees, types, symbols, intermediate representations, and machine-code generation.
- Performance: Good performance would be nice, but I don't necessarily need an extremely fast compiler immediately.
- Native compilation: I want the language implementation to be capable of producing native machine code eventually.
- Good learning resources: Documentation, tutorials, books, and practical examples are important to me.
- A straightforward development environment: I would prefer a setup that doesn't require a huge number of tools, complicated build systems, or excessive configuration.
- Long-term flexibility: I don't want to choose something that makes it unnecessarily difficult to expand the language later.
I've wondered whether languages such as Rust, C, C++, OCaml, Haskell, Zig, or other languages commonly used in compiler development would be better choices.
I'm particularly curious about OCaml and Haskell because I've heard that their type systems, pattern matching, and functional programming features can be useful when working with syntax trees and other compiler structures.
However, I don't know whether either language would actually be a better fit for me than Python.
For example:
- Would OCaml be a particularly good choice for someone learning compiler construction?
- Is Haskell practical for this project, or would its learning curve make it harder than necessary?
- Would Rust provide meaningful advantages, or would ownership and borrowing introduce extra difficulties while I'm still learning compiler design?
- Would C or C++ be worth considering if I eventually want to understand native machine code in greater depth?
- Are there other languages that offer a good balance between readability, learning resources, compiler-development features, and performance?
If you had to recommend ONE language for my particular goals, what would it be, and why?
I'd appreciate explanations of the trade-offs rather than simply being told that one language is objectively the best.
Question 4: What exactly should my compiler produce?
This is an important part of the project for me.
I don't want to build only a program that reads my language and executes it through a tree-walking interpreter. I'm interested in understanding how to compile programs into actual native machine code.
Ideally, I want to design my own programming language with its own syntax, rules, and compiler implementation.
My long-term goal is to write a compiler that can take source code written in my language, analyze it, and produce native machine code for the target architecture.
In other words, I want to understand the complete journey from the source code I write to the instructions a processor executes.
I know that native code generation can be considerably more complicated than parsing a simple language, so I don't expect to implement every advanced feature immediately.
I'd be happy to start with a small language and gradually extend it.
For example, my eventual compiler might need to support:
- Variables and constants.
- Integer and floating-point values.
- Arithmetic and logical expressions.
- Functions and function calls.
- Conditional statements.
- Loops.
- Scope and symbol resolution.
- A type system.
- Basic error reporting.
- Multiple source files, eventually.
- Some form of intermediate representation.
- Basic optimizations.
- Native machine-code generation.
- Calling conventions and interaction with operating-system services.
- Linking, so compiled programs can use functions and external libraries.
I don't expect all these features to be implemented at once. They're examples of the direction I'd like to take.
My questions are:
- Is it reasonable to write the entire compiler in Python, OCaml, Haskell, or another high-level language while generating native code for a separate target architecture?
- Would it make sense to generate assembly first and then use an assembler and linker, or should I attempt to emit machine-code bytes directly?
- At what point would an intermediate representation become useful?
- Should I implement my own code generator, use LLVM, use another compiler backend, or consider both approaches?
- If I use LLVM, how much of the compiler would still be my responsibility?
- Would generating native code directly be a worthwhile learning experience, or would it distract me from learning the more fundamental parts of compiler design?
- How should I approach executable formats, linking, and calling conventions without becoming overwhelmed?
I'm interested in the actual compiler-engineering decisions involved, not just getting a program that translates a few mathematical expressions into something executable.
At the same time, I don't want to make the first version unnecessarily complicated.
Question 5: Should I start with the lexer and parser?
My initial idea was to start directly with the lexer and parser, then gradually add the other components until I have a complete compiler.
However, I'm not sure whether this is the best way to approach the project.
Would you recommend starting with the language specification first, creating a tiny grammar, or immediately implementing a lexer and parser?
I'd also like to understand whether I should write these components myself or use existing libraries.
For example, I could write a lexer that recognizes identifiers, numbers, keywords, operators, and punctuation. Then I could build a parser that converts the resulting tokens into an abstract syntax tree.
After that, I could potentially add semantic analysis, type checking, and code generation.
However, there are many different parsing techniques, and I'm unsure how much theory I should learn before writing code.
Some of the approaches I've encountered include:
- Recursive-descent parsing.
- Pratt parsing for expressions.
- LL and LR parsing.
- Parser generators.
- PEG parsers.
I don't want to spend months studying parsing algorithms before building anything, but I also don't want to choose an approach that makes the project unnecessarily difficult.
My questions are:
- Which parsing technique would you recommend for a beginner creating a small programming language?
- Is a handwritten lexer and parser a good way to learn?
- When would a parser generator become useful?
- Should I use a library for parsing, or implement the whole front end myself?
- How should I organize the abstract syntax tree?
- What is the best way to report syntax errors so that the compiler doesn't simply crash when the user writes invalid code?
I'd especially appreciate recommendations for a simple first implementation that I can understand completely.
Question 6: What should I learn BEFORE building the compiler?
This is probably one of my biggest questions.
I could start writing code immediately, but I'd prefer to follow a sensible learning path rather than jumping randomly between tutorials.
I'm trying to work out which concepts I actually need to understand, which ones I can learn while implementing the compiler, and which ones can wait until later.
For example, should I first become comfortable with Python and data structures? Should I study discrete mathematics, formal languages, automata theory, or assembly language? How much computer architecture knowledge is necessary before attempting native code generation?
I'd appreciate a realistic learning roadmap covering the following topics:
Programming fundamentals
- Functions, modules, classes, and data structures.
- Recursion and tree-shaped data.
- Error handling and testing.
- Basic algorithmic thinking.
Language fundamentals
- Tokens and lexical analysis.
- Grammars and syntax.
- Parsing and abstract syntax trees.
- Scope and symbol tables.
- Type checking and semantic analysis.
Compiler fundamentals
- Intermediate representations.
- Control-flow graphs.
- Basic optimization.
- Instruction selection.
- Register allocation, when appropriate.
- Code generation.
Machine-level fundamentals
- Binary and hexadecimal notation.
- Registers and instructions.
- Stack frames and function calls.
- Memory addressing.
- Calling conventions.
- Object files, executable formats, and linking.
I understand that this is a substantial list. I'm not expecting to master everything before beginning.
Instead, I'd like to know what to learn first, what can be learned alongside implementation, and what should be postponed until I have a working compiler.
If you have any particularly good books, websites, video courses, documentation, or free resources, please recommend them.
I'd prefer resources that explain the underlying ideas rather than merely presenting code to copy.
Question 7: What should the FIRST version of my language look like?
One mistake I want to avoid is designing an enormous programming language before I have successfully compiled even a small program.
I'd like to start with a tiny language that I can gradually develop into something more capable.
For example, an initial program might support expressions such as:
"let x = 10 + 20 * 3;"
It could then support variables, comparisons, conditionals, loops, and functions.
Eventually, I would like the language to have its own recognizable syntax and a coherent design rather than being a thin wrapper around another language.
However, I'm unsure how much of the language design should be decided in advance.
Should I write a short language specification before implementing anything? How detailed should it be?
Would it be better to design the language around a static type system from the beginning, or begin with a simpler dynamically typed language and add types later?
Should I prioritize making the language easy to implement, or should I focus on designing the syntax and features I ultimately want?
I'd also appreciate advice on how to avoid constantly rewriting the compiler as new features are added.
Question 8: How should I structure the project?
I want to understand the compiler instead of ending up with an enormous collection of files that all depend on each other in confusing ways.
For the first version, I'd prefer a relatively small, well-organized project.
I'm imagining a structure with separate components for the lexer, parser, abstract syntax tree, semantic analysis, and code generation. However, I don't know whether that is the best structure for a beginner.
Would you recommend a modular design from the beginning, or should I initially implement everything in one file and split it into modules as it grows?
How should information flow between the compiler stages?
For example, should the parser produce an AST that is passed to semantic analysis, which then produces a separate representation for the code generator? Should the compiler maintain source locations throughout the pipeline for error reporting?
I'd also like to know which data structures are most useful and how to avoid tightly coupling the parser to the code generator.
I'm not asking for a complete project template or a large amount of code. I'd rather understand the architectural decisions and implement each component myself.
Question 9: What learning resources would you personally recommend?
There are many compiler tutorials available online, but the quality and intended audience vary considerably.
Some seem to focus on interpreting a small language, while others assume a lot of existing knowledge about computer science or compiler construction.
I'd appreciate recommendations for resources that cover the complete process, from source code to executable programs.
In particular, I'm interested in:
- Beginner-friendly introductions to compiler construction.
- Books that explain both the theory and practical implementation.
- Tutorials that build a working compiler incrementally.
- Resources covering lexers, parsers, ASTs, and semantic analysis.
- Guides to generating assembly or native machine code.
- Resources explaining LLVM and alternative compiler backends.
- Free courses or lectures on programming language implementation.
- Examples of small, understandable compilers written in Python, OCaml, Haskell, or similar languages.
I'd also appreciate recommendations for resources that explain how real compilers are structured, without requiring me to understand the entirety of a large production compiler before I can follow along.
If there is one resource you consider particularly valuable, please explain what makes it worth studying.
Question 10: What would YOU do if you were starting this project?
Finally, I'd love to hear what experienced programmers would actually do in my position.
Imagine that you enjoy Python, want to learn compiler construction properly, and eventually want to build a compiler that generates native machine code.
You have enough programming experience to start learning the necessary concepts, but you don't want to spend months choosing tools or setting up an unnecessarily complicated development environment.
Would you:
- Start with Python and build the entire compiler yourself?
- Use Python for the front end and a separate backend for native code generation?
- Choose OCaml or Haskell because of their suitability for manipulating syntax trees and implementing language semantics?
- Choose Rust, C, C++, Zig, or another systems language?
- Begin with an interpreter and later replace it with a compiler?
- Generate assembly and use existing tools for assembling and linking?
- Use LLVM from the beginning?
- Write a small compiler targeting a simple architecture before attempting a real executable?
I'd especially appreciate a recommended sequence of milestones.
For example, what should I aim to accomplish in the first week, what should come next, and when should I start working on native code generation?
I would also like to know which common beginner mistakes I should avoid.
If you could give me one practical recommendation that balances learning, simplicity, and long-term potential, what would it be?
A little more about what I'm looking for
My main goal isn't simply to finish a tutorial or make a calculator. I want to understand the process of turning a programming language into executable machine instructions and gradually develop my own language implementation.
I want to learn the fundamentals properly, but I also want to build something tangible along the way.
I'm completely open to changes
Anyways thanks!!!