Add support for listing symbols

src/main.rs

@@ -14,7 +14,10 @@ use crate::{
     m68k::{BusError, M68K},
 };
 use disas::DisassemblyError;
-use elf::symbol::Symbol;
+use elf::{
+    gabi::{STT_FILE, STT_SECTION},
+    symbol::Symbol,
+};
 use itertools::Itertools;
 use parse_int::parse;
 use reedline_repl_rs::{
@@ -425,11 +428,7 @@ fn main() -> Result<(), ReplError> {
     )
     .with_command(
         Command::new("sym")
-            .arg(
-                Arg::new("file")
-                    .required(true)
-                    .help("The ELF file to load symbols from"),
-            )
+            .arg(Arg::new("file").help("The ELF file to load symbols from"))
             .arg(
                 Arg::new("append")
                     .long("append")
@@ -437,9 +436,9 @@ fn main() -> Result<(), ReplError> {
                     .action(ArgAction::SetTrue)
                     .help("Append the file's symbols to the loaded list of symbols"),
             )
-            .about("Load symbols from an ELF file"),
+            .about("Load symbols from an ELF file, or list symbols if no file provided"),
         |args, state| {
-            let file = args.get_one::<String>("file").unwrap();
+            if let Some(file) = args.get_one::<String>("file") {
                 let file = elf::File::open_path(file).map_err(<Box<dyn error::Error>>::from)?;
                 let symtab = file
                     .get_section(".symtab")
@@ -453,6 +452,17 @@ fn main() -> Result<(), ReplError> {
                     state.symbols = symbols;
                 }
                 Ok(None)
+            } else {
+                #[allow(unstable_name_collisions)]
+                Ok(Some(
+                    state
+                        .symbols
+                        .iter()
+                        .map(ToString::to_string)
+                        .intersperse("\n".to_string())
+                        .collect::<String>(),
+                ))
+            }
         },
     )
     .with_command(