chore(avm): delete generated dir (#7741)

Use `-y` if you want to avoid the prompt.

bb-pilcom/bb-pil-backend/Cargo.toml

@@ -16,3 +16,4 @@ rand = "0.8.5"
 powdr-ast = { path = "../powdr/ast" }
 handlebars = { version = "5.1.2", features = ["string_helpers"] }
 serde_json = "1.0.120"
+dialoguer = "0.11.0"

bb-pilcom/bb-pil-backend/src/file_writer.rs

@@ -27,6 +27,13 @@ impl BBFiles {
         }
     }
 
+    pub fn remove_generated_dir(&self) {
+        let path = Path::new(&self.base_dir);
+        if path.exists() {
+            std::fs::remove_dir_all(path).unwrap();
+        }
+    }
+
     pub fn write_file(&self, folder: Option<&str>, filename: &str, contents: &str) {
         // attempt to create dir
         let base_path = Path::new(&self.base_dir).join(folder.unwrap_or(""));

bb-pilcom/bb-pil-backend/src/vm_builder.rs

@@ -1,3 +1,6 @@
+use dialoguer::Confirm;
+
+use itertools::Itertools;
 use powdr_ast::analyzed::Analyzed;
 use powdr_number::FieldElement;
 
@@ -56,6 +59,7 @@ pub fn analyzed_to_cpp<F: FieldElement>(
     witness: &[String],
     public: &[String],
     vm_name: &str,
+    delete_dir: bool,
 ) {
     // Extract public inputs information.
     let mut public_inputs: Vec<(String, usize)> = public
@@ -70,6 +74,17 @@ pub fn analyzed_to_cpp<F: FieldElement>(
     let witness = &sort_cols(witness);
 
     let mut bb_files = BBFiles::default(&snake_case(&vm_name));
+    // Pass `-y` as parameter if you want to skip the confirmation prompt.
+    let confirmation = delete_dir
+        || Confirm::new()
+            .with_prompt(format!("Going to remove: {}. OK?", bb_files.base_dir))
+            .default(true)
+            .interact()
+            .unwrap();
+    if confirmation {
+        println!("Removing generated directory: {}", bb_files.base_dir);
+        bb_files.remove_generated_dir();
+    }
 
     // Inlining step to remove the intermediate poly definitions
     let mut analyzed_identities = analyzed.identities_with_inlined_intermediate_polynomials();
@@ -169,6 +184,8 @@ pub fn analyzed_to_cpp<F: FieldElement>(
     // ----------------------- Create the Prover files -----------------------
     bb_files.create_prover_cpp(vm_name, &inverses);
     bb_files.create_prover_hpp(vm_name);
+
+    println!("Done with generation.");
 }
 
 /// Get all col names

bb-pilcom/cli/src/main.rs

@@ -20,6 +20,11 @@ struct Cli {
     /// BBerg: Name of the output file for bberg
     #[arg(long)]
     name: Option<String>,
+
+    /// Delete the output directory if it already exists
+    #[arg(short, long)]
+    #[arg(default_value_t = false)]
+    yes: bool,
 }
 
 fn extract_col_name(cols: Vec<&(Symbol, Option<FunctionValueDefinition>)>) -> Vec<String> {
@@ -47,6 +52,7 @@ fn main() -> Result<(), io::Error> {
         &extract_col_name(witness),
         &extract_col_name(public),
         &name,
+        args.yes,
     );
     Ok(())
 }