Add a flag to show the AST/Token list

src/main.rs

@@ -2,15 +2,23 @@ use compiler::{backend::spirv_meta, meta_compile};
 use error::print_error;
 use std::{env, fs, path::PathBuf};
 
-use parser::parse_string;
+use parser::{parse_string, tokenize, Token};
 pub mod compiler;
 mod error;
 pub mod parser;
 
+#[derive(Debug, Default, PartialEq)]
+enum Trace {
+    Tokens,
+    AST,
+    #[default] Normal
+}
+
 #[derive(Debug, Default)]
 struct CompilerArgs {
     input: Option<PathBuf>,
     output: Option<PathBuf>,
+    trace: Trace,
     print_help: bool,
     print_version: bool,
 }
@@ -43,6 +51,17 @@ fn main() {
             return;
         }
     };
+    if args.trace == Trace::Tokens {
+        let tokens = tokenize(&src);
+        for tok in tokens {
+            match tok.item {
+                Token::LeftParen => println!("{:>3}:{:<3} LeftParen",tok.location.line_start(), tok.location.col_start()),
+                Token::RightParen => println!("{:>3}:{:<3} RightParen",tok.location.line_start(), tok.location.col_start()),
+                Token::Symbol( val ) => println!("{:>3}:{:<3} Symbol `{}`",tok.location.line_start(), tok.location.col_start(), val)
+            }
+        }
+        return;
+    }
 
     let ast = match parse_string(&src) {
         Ok(i) => i,
@@ -51,6 +70,11 @@ fn main() {
             return;
         }
     };
+    
+    if args.trace == Trace::AST {
+        ast.pretty_print(None,None);
+        return;
+    }
 
     let module = match meta_compile(ast) {
         Ok(m) => m,
@@ -111,6 +135,36 @@ fn parse_args() -> CompilerArgs {
                         return parsed_args;
                     }
                 }
+                "trace" => {
+                    if parsed_args.trace == Trace::Normal {
+                        let Some(output) = args.next() else {
+                            parsed_args.print_help = true;
+                            eprintln!("trace needs a file");
+                            eprintln!();
+                            return parsed_args;
+                        };
+                        match output.as_str() {
+                            "ast" | "AST" | "Ast" => {
+                                parsed_args.trace = Trace::AST;
+                            }
+                            "token" | "tokens" => {
+                                parsed_args.trace = Trace::Tokens;
+                            }
+                            a => {
+                                eprintln!("unknown trace value {a}");
+                                eprintln!();
+                                parsed_args.print_help = true;
+                                return parsed_args;
+                            }
+                        }
+
+                    } else {
+                        eprintln!("trace can be passed only once");
+                        eprintln!();
+                        parsed_args.print_help = true;
+                        return parsed_args;
+                    }
+                }
                 a => {
                     eprintln!("unknown arg --{a}");
                     eprintln!();

src/parser/mod.rs

@@ -155,6 +155,31 @@ impl Ast {
             Ast::Root(_) => &Location::All,
         }
     }
+
+    pub fn pretty_print(&self, prefix: Option<&String>, body_prefix: Option<&String>) {
+        let empty_string_to_make_rust_happy = &String::from("");
+        let prefix_ = prefix.unwrap_or(&empty_string_to_make_rust_happy);
+        let body_prefix_ = body_prefix.unwrap_or(&empty_string_to_make_rust_happy);
+        match self {
+            Ast::Symbol(Localised { item, location }) => {
+                println!("{} Symbol `{}` ({}:{})", prefix_, item, location.line_start(), location.col_start());
+            },
+            Ast::List(Localised { item, location }) => {
+                println!("{} List ({}:{})", prefix_, location.line_start(), location.col_start());
+                for i in 0..item.len()-2 {
+                    item[i].pretty_print(Some(&(body_prefix_.to_owned() + &String::from(" ├─ "))), Some(&(body_prefix_.to_owned() + &String::from(" │  "))));
+                }
+                item[item.len()-1].pretty_print(Some(&(body_prefix_.to_owned() + &String::from(" ╰─ "))), Some(&(body_prefix_.to_owned() + &String::from("    "))));
+            },
+            Ast::Root( items ) => {
+                println!("{} Root", prefix_);
+                for i in 0..items.len()-2 {
+                    items[i].pretty_print(Some(&(body_prefix_.to_owned() + &String::from(" ├─ "))), Some(&(body_prefix_.to_owned() + &String::from(" │  "))));
+                }
+                items[items.len()-1].pretty_print(Some(&(body_prefix_.to_owned() + &String::from(" ╰─ "))), Some(&(body_prefix_.to_owned() + &String::from("    "))));
+            },
+        }
+    }
 }
 
 pub fn tokenize(input: &str) -> Vec<Localised<Token>> {