Hey there! Let’s tackle your three questions head-on, since building a DSL that leans on TypeScript’s syntax makes a lot of sense—but the tooling hurdles can be real.

1. Should I reuse TypeScript’s scanner/parser/binder, or build from scratch? #

Reusing TypeScript’s internal components is technically feasible, but it comes with significant tradeoffs:

• Pros: Since your DSL mirrors TS syntax/concepts, you’ll skip writing a ton of boilerplate for scanning, parsing, and binding types. You’ll also get TS’s battle-tested handling of edge cases (like tricky tokenization or scope resolution) for free.
• Cons: TypeScript’s internal APIs are not stable or documented for external use. The repo structure is complex, dependencies are tightly coupled, and any TS version update could break your custom modifications. Your issue with the scanner flagging unknown syntax as Identifier is a perfect example—you’d need to dig into the scanner’s source code to add custom token logic, which requires deep familiarity with how TS’s core components interact.

If your DSL is almost identical to TS with only minor tweaks, investing time to fork the TS repo and modify the relevant components might be worth it. But if your DSL has meaningful differences (even small ones), building from scratch will give you more flexibility, easier maintenance, and no reliance on TS’s internal churn.

2. Tools to help build a compiler from scratch in TypeScript/JavaScript #

Here are the top alternatives to Java’s ANTLR/javacc in the TS/JS ecosystem:

• Chevrotain: A pure TS/JS parser generator that supports both LL(k) and LR parsing. It has first-class TypeScript support, excellent documentation, and lets you define grammars directly in TS code. It’s a great pick if you want a robust, flexible tool similar to ANTLR.
• Ohm: A declarative parsing tool that uses a custom grammar language (Ohm Grammar) to define syntax. It’s incredibly easy to prototype with, and supports attaching semantic actions directly to grammar rules. Perfect for simpler DSLs or when you want to avoid writing low-level parser code.
• PEG.js: A mature PEG (Parsing Expression Grammar) generator that produces JS parsers. PEG syntax is intuitive for many developers, and PEG.js has a large community and plenty of examples. Great for medium-complexity DSLs.
• Recast: If your DSL is close to JS/TS syntax, Recast lets you parse existing JS/TS into ASTs, modify them, and generate code. It’s built on Espree (a JS parser) and can be extended to handle custom syntax nodes—saving you from building a scanner/parser from scratch.
• Esprima: A standard-compliant JS parser that outputs ESTree-compatible ASTs. You can use it as a base to extend JS syntax for your DSL, or just borrow its AST structure to align with existing tooling.

3. Learning resources beyond the TypeScript compiler itself #

• 《TypeScript Deep Dive》: This free online book has a dedicated section on TypeScript’s compiler architecture, breaking down how the scanner, parser, and binder work step-by-step. Even though it’s focused on TS, the core compiler concepts translate directly to building your own DSL.
• Compiler Explorer: Use this tool to inspect TypeScript’s AST output and see how TS transforms code. It’s a great way to visualize how syntax maps to AST nodes, which will help you design your own parser’s output.
• Crafting Interpreters: While written in Java and C, this classic book teaches fundamental compiler/interpreter concepts (scanning, parsing, semantic analysis, code generation) in a hands-on way. You can easily adapt the examples to TypeScript—many developers have even ported the book’s projects to TS.
• Open Source DSL Examples: Look at real-world TypeScript-based DSLs like Prisma Schema, Tailwind CSS’s configuration language, or even small script languages written in TS. Studying their code will give you practical insights into how to structure your own compiler components.
• YouTube Tutorials: Search for “Building a Compiler in TypeScript” to find playlists where developers walk through building a small language from scratch. These videos are great for seeing how to implement each compiler stage in practice.

内容的提问来源于stack exchange，提问作者superbadcodemonkey