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Paradigm(s) concurrent, functional, generic, imperative, structured
Designed by User:OliveIsAWord
Appeared in 2022
Computational class Unknown
Major implementations Rust
File extension(s) .indurate

Indurate, also known as Friable, is a subset of the Rust programming language focused on the safety, immutability, and elegance that is lost in the disgraceful, hedonistic use of Rust proper.


  • Use of mutability is prohibited. No variables or function arguments may be marked as `mut`. Any types which allow mutability, such as the mutable reference, are similarly barred.
  • Use of unsafe code is prohibited. Under no circumstances can an unsafe block be created, nor can any function or trait be marked as unsafe.
  • Given the sinful and flagrant breaches of the two previous points throughout the Rust standard library, any `use` therein is prohibited, including the prelude. This chiefly targets the `std` and `core` crates.

To assure no use of the standard library, all Indurate code should begin with:


Additionally, the code should be compiled in Rust edition 2018 or greater, to assure that the procedural macros as well do not seep in.


It is unclear if a useful binary could ever be created. Access to files, stdin/stdout, or any I/O functionality is unavailable. Additionally, any return value from the `main` function must implement the `std::process::Termination` trait, and as such the only possible return types are the unit type `()` and the never type `!`, neither of which can hold data. It might be possible to transmit one bit of information by deciding whether the program terminates; however, determining in the general case whether an Indurate program will terminate is currently not feasible. Nonetheless, like its parent language, library code is still entirely possible.

One major issue is allocating memory. Without that, the language would be reduced to FSA complexity. There is the unstable `box` keyword which is an alias for `Box::new()`, but it's unclear how to utilize it (e.g. by creating a linked list) without referencing the `Box` type itself.