3 ms·
I think writing a parser by hand should be reserved for when 1. You have users. 2. You can demonstrate a marked improvement in performance and/or error report
by zetalyrae 4y ago
I think writing a parser by hand should be reserved for when
1. You have users.
2. You can demonstrate a marked improvement in performance and/or error reporting with the hand-written parser.
Otherwise, deriving a parser from a grammar should absolutely be the default. Writing parsers by hand is error-prone, causes security vulnerabilities[0], and is very tedious work.
[0]: http://langsec.org/ http://langsec.org/
- t-3 4y ago3. Your language has very little/no syntax. A parser for a Forth is a one-liner or a short loop in most languages.
- mhzsh 4y ago4. You want to learn how to implement a parser by hand.
- pianoben 4y agoHaving written production-level compilers, my advice: use ANTLR for as long as humanly possible. It can remain adequate far, far longer than you think, and will save you months/years of stress. When you outgrow it, you'll know - and by then, hopefully you'll have funding/users/contributors/etc to support the dev effort of rolling your own parser.
- matijash 4y agoOur compiler stack is in Haskell so we initially started with Parsec (parser combinator library) and then eventually switched to Happy (parser generator that Haskell uses itself) since at first we didn't have a formal grammar defined so that made us write a lot of code for every little addition to the language (it's a simple declarative DSL, https://github.com/wasp-lang/wasp https://github.com/wasp-lang/wasp). The problem we're now facing with Happy is that it doesn't really have support for error recovery. We're trying to implement LSP so recovery is important in order to have proper syntax highlighting and error reporting in an IDE. Wondering how well ANTLR covers this, I was quite surprised to find out that Happy has so little support for it.
- DylanSp 4y agoIIRC Happy (and Alex, the accompanying lexer generator) are pretty much straight ports of lex/yacc to Haskell; they predate some of the conveniences of newer parser generators like ANTLR.
- rowanG077 4y agoI would have the opposite advice. Derived parsers have shit errors. Which is arguebly the most important feature of a parser besides being able to parse. And writing parsers by hand is trivial anyway. In a lot of cases if you squint a little you can see the BNF.