Create a separate dev crate for development scripts (#607)

ruff_dev/src/generate_check_code_prefix.rs

@@ -0,0 +1,140 @@
+//! Generate the `CheckCodePrefix` enum.
+
+use std::collections::{BTreeMap, BTreeSet};
+use std::fs::OpenOptions;
+use std::io::Write;
+
+use anyhow::Result;
+use clap::Parser;
+use codegen::{Scope, Type, Variant};
+use itertools::Itertools;
+use ruff::checks::CheckCode;
+use strum::IntoEnumIterator;
+
+const FILE: &str = "src/checks_gen.rs";
+
+#[derive(Parser)]
+#[command(author, version, about, long_about = None)]
+pub struct Cli {
+    /// Write the generated source code to stdout (rather than to
+    /// `src/checks_gen.rs`).
+    #[arg(long)]
+    dry_run: bool,
+}
+
+pub fn main(cli: &Cli) -> Result<()> {
+    // Build up a map from prefix to matching CheckCodes.
+    let mut prefix_to_codes: BTreeMap<String, BTreeSet<CheckCode>> = Default::default();
+    for check_code in CheckCode::iter() {
+        let as_ref: String = check_code.as_ref().to_string();
+        let prefix_len = as_ref
+            .chars()
+            .take_while(|char| char.is_alphabetic())
+            .count();
+        for i in prefix_len..=as_ref.len() {
+            let prefix = as_ref[..i].to_string();
+            let entry = prefix_to_codes.entry(prefix).or_default();
+            entry.insert(check_code.clone());
+        }
+    }
+
+    let mut scope = Scope::new();
+
+    // Create the `CheckCodePrefix` definition.
+    let mut gen = scope
+        .new_enum("CheckCodePrefix")
+        .vis("pub")
+        .derive("EnumString")
+        .derive("Debug")
+        .derive("PartialEq")
+        .derive("Eq")
+        .derive("PartialOrd")
+        .derive("Ord")
+        .derive("Clone")
+        .derive("Serialize")
+        .derive("Deserialize");
+    for prefix in prefix_to_codes.keys() {
+        gen = gen.push_variant(Variant::new(prefix.to_string()));
+    }
+
+    // Create the `PrefixSpecificity` definition.
+    scope
+        .new_enum("PrefixSpecificity")
+        .vis("pub")
+        .derive("PartialEq")
+        .derive("Eq")
+        .derive("PartialOrd")
+        .derive("Ord")
+        .push_variant(Variant::new("Category"))
+        .push_variant(Variant::new("Hundreds"))
+        .push_variant(Variant::new("Tens"))
+        .push_variant(Variant::new("Explicit"));
+
+    // Create the `match` statement, to map from definition to relevant codes.
+    let mut gen = scope
+        .new_impl("CheckCodePrefix")
+        .new_fn("codes")
+        .arg_ref_self()
+        .ret(Type::new("Vec<CheckCode>"))
+        .vis("pub")
+        .line("match self {");
+    for (prefix, codes) in &prefix_to_codes {
+        gen = gen.line(format!(
+            "CheckCodePrefix::{prefix} => vec![{}],",
+            codes
+                .iter()
+                .map(|code| format!("CheckCode::{}", code.as_ref()))
+                .join(", ")
+        ));
+    }
+    gen.line("}");
+
+    // Create the `match` statement, to map from definition to specificity.
+    let mut gen = scope
+        .new_impl("CheckCodePrefix")
+        .new_fn("specificity")
+        .arg_ref_self()
+        .ret(Type::new("PrefixSpecificity"))
+        .vis("pub")
+        .line("match self {");
+    for prefix in prefix_to_codes.keys() {
+        let num_numeric = prefix.chars().filter(|char| char.is_numeric()).count();
+        let specificity = match num_numeric {
+            3 => "Explicit",
+            2 => "Tens",
+            1 => "Hundreds",
+            0 => "Category",
+            _ => panic!("Invalid prefix: {}", prefix),
+        };
+        gen = gen.line(format!(
+            "CheckCodePrefix::{prefix} => PrefixSpecificity::{},",
+            specificity
+        ));
+    }
+    gen.line("}");
+
+    // Construct the output contents.
+    let mut output = String::new();
+    output.push_str("//! File automatically generated by examples/generate_check_code_prefix.rs.");
+    output.push('\n');
+    output.push('\n');
+    output.push_str("use serde::{{Serialize, Deserialize}};");
+    output.push('\n');
+    output.push_str("use strum_macros::EnumString;");
+    output.push('\n');
+    output.push('\n');
+    output.push_str("use crate::checks::CheckCode;");
+    output.push('\n');
+    output.push('\n');
+    output.push_str(&scope.to_string());
+
+    // Write the output to `src/checks_gen.rs` (or stdout).
+    if cli.dry_run {
+        println!("{}", output);
+    } else {
+        let mut f = OpenOptions::new().write(true).truncate(true).open(FILE)?;
+        write!(f, "{}", output)?;
+    }
+
+    Ok(())
+}