Merge #775

775: feat(repl): add a --no-std option to the standalone interpreter / REPL r=Marwes a=Etherian

## Description
Adds a command-line switch `--no-std` to the standalone interpreter / REPL which causes it to ignore its internal standard library modules when searching for modules to import.

This should make less awkward to use the REPL to test changes to the standard library.

resolves #751 

Co-authored-by: Etherian <etherain@gmail.com>

repl/src/main.rs

@@ -79,7 +79,7 @@ impl ::std::str::FromStr for Color {
             "always" => Always,
             "always-ansi" => AlwaysAnsi,
             "never" => Never,
-            _ => return Err("Expected on of auto, always, always-ansi, never"),
+            _ => return Err("Expected one of 'auto', 'always', 'always-ansi', 'never'"),
         })
     }
 }
@@ -129,6 +129,12 @@ pub struct Opt {
     )]
     debug_level: base::DebugLevel,
 
+    #[structopt(
+        long = "no-std",
+        help = "Skip searching the internal standard library for requested modules."
+    )]
+    no_std: bool,
+
     #[structopt(name = "FILE", help = "Executes each file as a gluon program")]
     input: Vec<String>,
 
@@ -155,8 +161,8 @@ fn init_env_logger() {
 #[cfg(not(feature = "env_logger"))]
 fn init_env_logger() {}
 
-fn format(file: &str, file_map: Arc<codespan::FileMap>) -> Result<String> {
-    let mut compiler = Compiler::new();
+fn format(file: &str, file_map: Arc<codespan::FileMap>, opt: &Opt) -> Result<String> {
+    let mut compiler = Compiler::new().use_standard_lib(!opt.no_std);
     let thread = new_vm();
 
     Ok(compiler.format_expr(
@@ -167,7 +173,7 @@ fn format(file: &str, file_map: Arc<codespan::FileMap>) -> Result<String> {
     )?)
 }
 
-fn fmt_file(name: &Path) -> Result<()> {
+fn fmt_file(name: &Path, opt: &Opt) -> Result<()> {
     use std::fs::File;
     use std::io::Read;
 
@@ -180,7 +186,7 @@ fn fmt_file(name: &Path) -> Result<()> {
     let module_name = filename_to_module(&name.display().to_string());
     let mut code_map = codespan::CodeMap::new();
     let file_map = code_map.add_filemap(module_name.clone().into(), buffer);
-    let formatted = format(&module_name, file_map.clone())?;
+    let formatted = format(&module_name, file_map.clone(), opt)?;
 
     // Avoid touching the .glu file if it did not change
     if file_map.src() != formatted {
@@ -196,7 +202,7 @@ fn fmt_file(name: &Path) -> Result<()> {
     Ok(())
 }
 
-fn fmt_stdio() -> Result<()> {
+fn fmt_stdio(opt: &Opt) -> Result<()> {
     use std::io::{stdin, stdout, Read};
 
     let mut buffer = String::new();
@@ -205,7 +211,7 @@ fn fmt_stdio() -> Result<()> {
     let mut code_map = codespan::CodeMap::new();
     let file_map = code_map.add_filemap("STDIN".into(), buffer);
 
-    let formatted = format("STDIN", file_map)?;
+    let formatted = format("STDIN", file_map, opt)?;
     stdout().write_all(formatted.as_bytes())?;
     Ok(())
 }
@@ -241,10 +247,10 @@ fn run(
                 gluon_files.dedup();
 
                 for file in gluon_files {
-                    fmt_file(&file)?;
+                    fmt_file(&file, opt)?;
                 }
             } else {
-                fmt_stdio()?;
+                fmt_stdio(opt)?;
             }
         }
         Some(SubOpt::Doc(ref doc_opt)) => {
@@ -275,7 +281,9 @@ fn main() {
 
     let opt = Opt::from_args();
 
-    let mut compiler = Compiler::new().run_io(true);
+    let mut compiler = Compiler::new()
+        .run_io(true)
+        .use_standard_lib(!opt.no_std);
     let vm = new_vm();
 
     if let Err(err) = run(&opt, &mut compiler, opt.color, &vm) {

src/import.rs

@@ -171,6 +171,7 @@ impl<I> Import<I> {
 
     fn get_unloaded_module(
         &self,
+        compiler: &mut Compiler,
         vm: &Thread,
         module: &str,
         filename: &str,
@@ -180,10 +181,11 @@ impl<I> Import<I> {
         // Retrieve the source, first looking in the standard library included in the
         // binary
 
-        let std_file = STD_LIBS.iter().find(|tup| tup.0 == module);
-        if let Some(tup) = std_file {
-            return Ok(UnloadedModule::Source(Cow::Borrowed(tup.1)));
-        }
+        let std_file = if compiler.settings.use_standard_lib {
+            STD_LIBS.iter().find(|tup| tup.0 == module)
+        } else {
+            None
+        };
         Ok(match std_file {
             Some(tup) => UnloadedModule::Source(Cow::Borrowed(tup.1)),
             None => {
@@ -309,7 +311,7 @@ impl<I> Import<I> {
         // Retrieve the source, first looking in the standard library included in the
         // binary
         let unloaded_module = self
-            .get_unloaded_module(vm, &modulename, &filename)
+            .get_unloaded_module(compiler, vm, &modulename, &filename)
             .map_err(|err| (None, err.into()))?;
 
         match unloaded_module {

src/lib.rs

@@ -256,6 +256,7 @@ struct Settings {
     emit_debug_info: bool,
     run_io: bool,
     full_metadata: bool,
+    use_standard_lib: bool,
 }
 
 impl Default for Settings {
@@ -265,6 +266,7 @@ impl Default for Settings {
             emit_debug_info: true,
             run_io: false,
             full_metadata: false,
+            use_standard_lib: true,
         }
     }
 }
@@ -345,6 +347,12 @@ impl Compiler {
         full_metadata set_full_metadata: bool
     }
 
+    option_settings! {
+        /// Sets whether internal standard library is searched for requested modules
+        /// (default: true)
+        use_standard_lib set_use_standard_lib: bool
+    }
+
     fn state(&self) -> MutexGuard<State> {
         self.state.lock().unwrap()
     }