init cli entrypoint

bin/Cargo.toml

@@ -6,3 +6,7 @@ edition = "2018"
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [dependencies]
+lib = { path = "../lib" }
+ariadne = "0.1.3"
+anyhow = "1.0"
+rnix = "0.9.0"

bin/src/main.rs

@@ -1,3 +1,82 @@
-fn main() {
-    println!("Hello, world!");
+use std::{
+    env, fs,
+    path::{Path, PathBuf},
+};
+
+use anyhow::{Context, Result};
+use ariadne::{Color, Fmt, Label, Report as CliReport, ReportKind as CliReportKind, Source};
+use lib::{Report, LINTS};
+use rnix::WalkEvent;
+
+fn analyze(file: &str) -> Result<Vec<Report>> {
+    let parsed = rnix::parse(file).as_result()?;
+
+    Ok(parsed
+        .node()
+        .preorder_with_tokens()
+        .filter_map(|event| match event {
+            WalkEvent::Enter(child) => LINTS.get(&child.kind()).map(|rules| {
+                rules
+                    .iter()
+                    .filter_map(|rule| rule.validate(&child))
+                    .collect::<Vec<_>>()
+            }),
+            _ => None,
+        })
+        .flatten()
+        .collect())
+}
+
+fn print_report(report: Report, file_src: &str, file_path: &Path) -> Result<()> {
+    let src_id = file_path.to_str().unwrap_or("<unknown>");
+    let offset = report
+        .diagnostics
+        .iter()
+        .map(|d| d.at.start().into())
+        .min()
+        .unwrap_or(0usize);
+    report
+        .diagnostics
+        .iter()
+        .fold(
+            CliReport::build(CliReportKind::Warning, src_id, offset),
+            |cli_report, diagnostic| {
+                let range = {
+                    let at = diagnostic.at;
+                    at.start().into()..at.end().into()
+                };
+                cli_report.with_label(
+                    Label::new((src_id, range))
+                        .with_message(diagnostic.message.as_str().fg(Color::Yellow)),
+                )
+            },
+        )
+        .finish()
+        .print((src_id, Source::from(file_src)))
+        .context("failed to print report to stdout")
+}
+
+fn _main() -> Result<()> {
+    let args = env::args();
+    for (file_src, file_path, reports) in args
+        .map(|s| PathBuf::from(&s))
+        .filter(|p| p.is_file())
+        .filter_map(|path| {
+            let s = fs::read_to_string(&path).ok()?;
+            analyze(&s)
+                .map(|analysis_result| (s, path, analysis_result))
+                .ok()
+        })
+    {
+        for r in reports {
+            print_report(r, &file_src, &file_path)?
+        }
+    }
+    Ok(())
+}
+fn main() {
+    match _main() {
+        Err(e) => eprintln!("{}", e),
+        _ => {}
+    }
 }