Change the regex to be lazy (#30)

Cargo.toml

@@ -19,6 +19,7 @@ serde = { version = "1.0", features = ["derive"] }
 tempfile = "3"
 toml = "0.5"
 regex = "1.5.4"
+once_cell = "1.8.0"
 
 [target.'cfg(windows)'.dependencies]
 cargo-temp-bindings = { path = "cargo-temp-bindings", version = "^0.0" }

README.md

@@ -58,22 +58,22 @@ When you run `cargo-temp` for the first time it will be created automatically.
 We use the [XDG system](https://docs.rs/xdg/2.2.0/xdg/) for both Linux and OSX
 and the [Know Folder system](https://docs.rs/dirs-2/3.0.1/dirs_2/) on Windows.
 
-### `temporary_project_dir`
+### Temporary project directory
 
 The path where the temporary projects are created.
 Set on the cache directory by default.
 
 `temporary_project_dir = "/home/name/.cache/cargo-temp/"`
 
-### `cargo_target_dir`
+### Cargo target directory
 
 Cargo's target directory override.
 This setting is unset by default and will be ignored if the `CARGO_TARGET_DIR`
 environment variable is already set.
 
 `temporary_project_dir = "/home/name/repos/tmp"`
 
-### editor
+### Editor
 
 You can use `editor` to start an IDE instead of a shell
 and `editor_args` to provide its arguments. These settings are unset by default.

src/main.rs

@@ -1,5 +1,6 @@
 use anyhow::{bail, Context, Result};
 use clap::Clap;
+use once_cell::sync::Lazy;
 use regex::Regex;
 use serde::{Deserialize, Serialize};
 use std::io::Write;
@@ -226,11 +227,14 @@ fn get_shell() -> String {
 }
 
 fn parse_dependency(s: &str) -> Dependency {
-    let regex =
+    // This will change when `std::lazy` is released.
+    // See https://github.com/rust-lang/rust/issues/74465.
+    static RE: Lazy<Regex> = Lazy::new(|| {
         Regex::new(r"^([^=]+)=(((\w+://([^:@]+(:[^@]+)?@)?[^#]+)(#branch=(.+)|#rev=(.+))?)|.+)$")
-            .unwrap();
+            .unwrap()
+    });
 
-    if let Some(caps) = regex.captures(s) {
+    if let Some(caps) = RE.captures(s) {
         if let Some(url) = caps.get(4) {
             Dependency::Repository {
                 name: caps[1].to_string(),