Mention minimum Rust in README
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+[![Minimum rustc version](https://img.shields.io/badge/rustc-1.20+-lightgray.svg)](#rust-version-requirements)
nom is a parser combinators library written in Rust. Its goal is to provide tools to build safe parsers without compromising the speed or memory consumption. To that end, it uses extensively Rust's *strong typing* and *memory safety* to produce fast and correct parsers, and provides macros and traits to abstract most of the error prone plumbing.
@@ -176,6 +177,13 @@ nom parsers are for:
Some benchmarks are available on [Github](https://github.com/Geal/nom_benchmarks).
+## Rust version requirements
+
+The 4.0 series of nom requires **Rustc version 1.20 or greater**.
+
+Travis CI always has a build with a pinned version of Rustc matching the oldest supported Rust release.
+The current policy is that this will only be updated in the next major nom release.
+
## Installation
nom is available on [crates.io](https://crates.io/crates/nom) and can be included in your Cargo enabled project like this:
