feat(cli): Add colors to CLI help outputs

Author: alerque

Cargo.toml

@@ -84,7 +84,7 @@ version = "0.8"
 [dependencies.clap]
 version = "4.4"
 optional = true
-features = ["derive", "string", "wrap_help"]
+features = ["color", "derive", "string", "wrap_help"]
 
 [dependencies.mlua]
 workspace = true

src/bin/sile.rs

@@ -1,4 +1,4 @@
-use sile::cli::Cli;
+use sile::cli::{Cli, STYLES};
 
 use snafu::prelude::*;
 
@@ -34,7 +34,10 @@ fn main() -> Result<()> {
         .strip_prefix("SILE ")
         .unwrap_or("")
         .to_string();
-    let app = Cli::command().version(version).long_version(long_version);
+    let app = Cli::command()
+        .version(version)
+        .long_version(long_version)
+        .styles(STYLES);
     let matches = app.get_matches();
     let args = Cli::from_arg_matches(&matches).context(ArgsSnafu)?;
     sile::run(

src/cli.rs

@@ -1,3 +1,4 @@
+use clap::builder::styling::{AnsiColor, Styles};
 use clap::Parser;
 use std::path::PathBuf;
 
@@ -146,3 +147,12 @@ pub struct Cli {
     #[clap(short, long)]
     pub traceback: bool,
 }
+
+pub const STYLES: Styles = Styles::styled()
+    .header(AnsiColor::Magenta.on_default().bold())
+    .usage(AnsiColor::Yellow.on_default().bold())
+    .literal(AnsiColor::BrightCyan.on_default().bold())
+    .placeholder(AnsiColor::Cyan.on_default())
+    .error(AnsiColor::BrightRed.on_default().bold())
+    .valid(AnsiColor::BrightGreen.on_default().bold())
+    .invalid(AnsiColor::BrightYellow.on_default().bold());