Show HN: Cdecl-dump - represent C declarations visually (github.com)

35 points by bluetomcat 7mo ago ↗ HN

A small tool that parses C declarations and outputs a simple visual representation at each stage, as it encounters arrays, pointers or functions.

The program uses a table-driven lexer and a hand-written, shift-reduce parser. No external dependencies apart from the standard library.

3 comments

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coherentpony 7mo ago ↗

I don’t understand what the visualisation screenshot in the README is trying to communicate to me.

pcfwik 7mo ago ↗

Since this is about C declarations: for anyone who (like me) had the misfortune of learning the so-called "spiral rule" in college rather than being taught how declarations in C work, below are some links that explain the "declaration follows use" idea that (AFAIK) is the true philosophy behind C declaration syntax (and significantly easier to remember/read/write).

TL;DR: you declare a variable in C _in exactly the same way you would use it:_ if you know how to use a variable, then you know how to read and write a declaration for it.

https://eigenstate.org/notes/c-decl https://news.ycombinator.com/item?id=12775966

xvilka 7mo ago ↗

We use the tree-sitter[1] for parsing C declarations in Rizin[2] (see the "td" command, for example). See our custom grammar[3] (modified mainstream tree-sitter-c). The custom grammar was sadly necessary, due to the inability of Tree-Sitter to have the alternate roots[4].

P.S. Please add a license for your code.

[1] https://tree-sitter.github.io/

[2] https://github.com/rizinorg/rizin/tree/dev/librz/type/parser

[3] https://github.com/rizinorg/rizin-grammar-c/

[4] https://github.com/tree-sitter/tree-sitter/issues/711