fst VS getopt

I'd point you towards BurntSushi's fst crate: https://github.com/BurntSushi/fst

The fst crate effectively relies on mmap for it to work right. The folks here suggesting you just use the heap might be right, but only if using the heap is actually plausible. If your dictionary is GBs big (an FST might be bigger than available memory), then copying it the heap first would be disastrous.

You'll love what we're working on if you're interested in the implementation of:- Tantivy- Meilisearch- Finite State Transducers

Here's an example of longest prefix matching using a FST which I based my approach on: https://github.com/BurntSushi/fst/pull/104/files

Finite State Transducers

As a result, I have a plan to implement a desktop version from then and I finished today with a beta version. The desktop is based on tauri, and the dictionary index algorithm is FST (it is an awesome index algorithm).

WordBueno’s data is currently derived from Wiktionary. The backend is using Rust’s warp with fst for indexing.

No you don't. I've written multiple programs that load things instantly off the file system via memory maps. See the fst crate[1], for example, which is designed to work with memory maps.

Rust "works badly with memory mapped files" doesn't mean, "Rust can't use memory mapped files." It means, "it is difficult to reconcile Rust's safety story with memory maps." ripgrep for example uses memory maps because they are faster sometimes, and its safety contract[2] is a bit strained. But it works.

[1] - https://github.com/BurntSushi/fst/

[2] - https://docs.rs/grep-searcher/0.1.7/grep_searcher/struct.Mma...

Between -std=c99 and removing these headers, you're missing time definitions (struct timeval, gettimeofday) and option parsing definitions (struct option, getopt_long). Mingw-w64 provides all this for compatibility, but MSVC has none of these, so you'll need to write replacements. I've written embeddable, public domain implementations of getopt and something like getopt_long, in case that helps. These are how I deal with option parsing portability.

The option parser is crude and doesn't follow conventions. Particularly the lack of -- support (disables option parsing) would make it impossible to use safely in scripts. If you don't want to use the system or toolchain-provided getopt, here's a public domain, embeddable implementation: getopt.h

On unix-like systems there's a getopt function for parsing short options. Mingw-w64 has one as well, to cover Windows programs. If I care about portability, I just embed my own so it not only works everywhere, it behave the same everywhere, too.

https://github.com/skeeto/getopt/blob/master/getopt.h (short)

Not only the GNU, you have an example in this thread where someone suggested to use or roll something similar to https://github.com/skeeto/getopt/blob/master/getopt.h, which, surprise, depends on strchr, a function that solves a much trivial problem than POSIX getopt, to begin with.