![]() Sadly, # is currently unable to override the original #, which makes this technique unusable in practice (I've already mentioned this issue to and the fix is trivial to write, but whether # ought to be able to override a # is a more debatable thing hence why I'm waiting on their green light). It does involve an extra helper crate, and breaks $crate, basically featuring the main drawbacks of procedural macros.Īnother approach is to #-tag the macro, and mangle a bit the name, so that in practice it doesn't really pollute the top-level module: # Object-like macros resemble data objects when used, function-like macros resemble function calls. They differ mostly in what they look like when they are used. Whenever the name is used, it is replaced by the contents of the macro. ![]() The most robust but also cumbersome way is to involve an extra helper crate to perform the #s of those macros for use, and then we can pub use ::that_helper_crate::macro_name within the module of our choosing. A macro is a fragment of code which has been given a name. There are two ways to palliate the issue: So this, indeed, pollutes the top-level module of the crate with that macro. In that case, for a macro_rules! macro, annotating the macro with # is necessary, and this will kind of magically perform a pub use path::to::that_macro at the root of the crate. It is also known as the ternary operator in C as it operates on three operands. Sometimes we may need this behavior (that of namespacing a macro within a module) but for a fully pub macro, since we just want to namespace a public / downstream-user-facing macro_rules! macro. The conditional operator in C is kind of similar to the if-else statement as it follows the same algorithm as of if-else statement but the conditional operator takes less space and helps to write the if-else statements in the shortest way possible. Macro exports being what they are, this: mod module Īt that point, you have escaped the macro idiosyncrasies, and then you are back to a good old namespacing / re-exporting problem.Īnswering the original thread's title / XY problem: quid of #ed macros? h files Is there any way to compile and run Loop() from command block rather than everytime having to quoteroot -l macro.C macro m m. Thing is, I'd like to be able to call that proc-macro any number of times in a given crate, including more than once. Hi I apologize if my question is stupid, but here it is After making the class from the root file, I have the. I have a proc-macro that, among a bunch of other things, generates definitions for a number macro_rules! macros. ![]()
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