correct handling of ! in phrase/{2,3}, get rid of extraneous choice points in put_atts/2 and get_atts/2, allow loading of non-module files from the command line and use_module/{2,3}

src/prolog/lib/atts.pl

@@ -33,7 +33,7 @@
 
 '$add_to_list'(Ls, V, Attr) :-
     ( var(Ls) -> Ls = [Attr | _], '$enqueue_attr_var'(V)
-    ; Ls = [_ | Ls0] -> '$add_to_list'(Ls0, V, Attr)
+    ; Ls = [_ | Ls0], '$add_to_list'(Ls0, V, Attr)
     ).
 
 '$del_attr'(Ls0, _, _) :-
@@ -89,7 +89,7 @@ get_attrs_var_check -->
 put_attrs(Name/Arity) -->
     put_attr(Name, Arity),
     { numbervars([Var, Attr], 0, _) },
-    [(put_atts(Var, Attr) :- lists:maplist(put_atts(Var), Attr))].
+    [(put_atts(Var, Attr) :- lists:maplist(put_atts(Var), Attr), !)].
 put_attrs((Name/Arity, Atts)) -->
     { nonvar(Atts) },
     put_attr(Name, Arity),

src/prolog/lib/dcgs.pl

@@ -9,6 +9,8 @@ phrase(G, G) :-
     nonvar(G), G = [_|_], !.
 phrase(G, Ls0) :-
     nonvar(G), G = (G1, G2), !, phrase(G1, Ls0, Ls1), phrase(G2, Ls1, []).
+phrase(G, Ls0) :-
+    nonvar(G), G == !, !, Ls0 = [].
 phrase(G, Ls0) :-
     call(G, Ls0, []).
 
@@ -17,6 +19,8 @@ phrase(G, Ls0, Ls1) :-
 phrase(G, Ls0, Ls2) :-
     nonvar(G), G = (G1, G2), !,
     phrase(G1, Ls0, Ls1), phrase(G2, Ls1, Ls2).
+phrase(G, Ls0, Ls1) :-
+    nonvar(G), G == !, !, Ls0 = [], Ls1 = [].
 phrase(G, Ls0, Ls1) :-
     call(G, Ls0, Ls1).
 

src/prolog/machine/compile.rs

@@ -56,8 +56,8 @@ fn fix_filename(atom_tbl: TabledData<Atom>, filename: &str) -> Result<PathBuf, S
     Ok(path)
 }
 
-fn load_module<R: Read>(wam: &mut Machine, name: &str, stream: ParsingStream<R>)
+fn load_module<R: Read>(wam: &mut Machine, stream: ParsingStream<R>)
-                        -> Result<ClauseName, SessionError>
+                        -> Result<Option<ClauseName>, SessionError>
 {
     // follow the operation of compile_user_module, but before
     // compiling, check that a module is declared in the file. if not,
@@ -69,10 +69,9 @@ fn load_module<R: Read>(wam: &mut Machine, name: &str, stream: ParsingStream<R>)
     let results = compiler.gather_items(wam, stream, &mut indices)?;
 
     let module_name = if let Some(ref module) = &compiler.module {
-        module.module_decl.name.clone()
+        Some(module.module_decl.name.clone())
     } else {
-        let module_name = clause_name!(name.to_string(), wam.indices.atom_tbl);
+        None
-        return Err(SessionError::NoModuleDeclaration(module_name));
     };
 
     match compile_work_impl(&mut compiler, wam, indices, results) {
@@ -82,7 +81,8 @@ fn load_module<R: Read>(wam: &mut Machine, name: &str, stream: ParsingStream<R>)
 }
 
 pub(super)
-fn load_module_from_file(wam: &mut Machine, filename: &str) -> Result<ClauseName, SessionError>
+fn load_module_from_file(wam: &mut Machine, filename: &str)
+                         -> Result<Option<ClauseName>, SessionError>
 {
     let path = fix_filename(wam.indices.atom_tbl.clone(), filename)?;
 
@@ -91,8 +91,7 @@ fn load_module_from_file(wam: &mut Machine, filename: &str) -> Result<ClauseName
         Err(SessionError::InvalidFileName(filename))
     })?;
 
-    let file_stem = path.file_stem().unwrap().to_string_lossy();
+    load_module(wam, parsing_stream(file_handle))
-    load_module(wam, &file_stem, parsing_stream(file_handle))
 }
 
 pub type PredicateCompileQueue = (Predicate, VecDeque<TopLevel>);
@@ -468,9 +467,13 @@ fn add_non_module_code(
 }
 
 pub(super)
-fn load_library(wam: &mut Machine, name: ClauseName) -> Result<ClauseName, SessionError> {
+fn load_library(wam: &mut Machine, name: ClauseName) -> Result<ClauseName, SessionError>
+{
     match LIBRARIES.borrow().get(name.as_str()) {
-        Some(code) => load_module(wam, name.as_str(), parsing_stream(code.as_bytes())),
+        Some(code) => {
+            let module_name = load_module(wam, parsing_stream(code.as_bytes()))?;
+            module_name.ok_or(SessionError::NoModuleDeclaration(name))
+        }
         None => Err(SessionError::ModuleNotFound)
     }
 }
@@ -767,18 +770,28 @@ impl ListingCompiler {
             }
             Declaration::UseModule(ModuleSource::File(filename)) => {
                 let name = load_module_from_file(wam, filename.as_str())?;
-                self.use_module(name, &mut wam.code_repo, flags, &mut wam.indices, indices)
+
+                if let Some(name) = name {
+                    self.use_module(name, &mut wam.code_repo, flags, &mut wam.indices, indices)
+                } else {
+                    Ok(())
+                }
             }
             Declaration::UseQualifiedModule(ModuleSource::File(filename), exports) => {
                 let name = load_module_from_file(wam, filename.as_str())?;
-                self.use_qualified_module(
+
-                    name,
+                if let Some(name) = name {
-                    &mut wam.code_repo,
+                    self.use_qualified_module(
-                    flags,
+                        name,
-                    &exports,
+                        &mut wam.code_repo,
-                    &mut wam.indices,
+                        flags,
-                    indices,
+                        &exports,
-                )
+                        &mut wam.indices,
+                        indices,
+                    )
+                } else {
+                    Ok(())
+                }
             }
 	    Declaration::ModuleInitialization(query_terms, queue) => {
 		self.initialization_goals.0.extend(query_terms.into_iter());

src/prolog/machine/mod.rs

@@ -430,22 +430,28 @@ impl Machine {
 	let load_result = match to_src(name) {
 	    ModuleSource::Library(name) =>
 		if !self.indices.modules.contains_key(&name) {
-		    load_library(self, name)
+		    load_library(self, name).map(Some)
 		} else {
-		    Ok(name)
+		    Ok(Some(name))
 		},
-	    ModuleSource::File(name) => load_module_from_file(self, name.as_str())
+	    ModuleSource::File(name) =>
+                load_module_from_file(self, name.as_str())
 	};
 
-	let result = load_result.and_then(|name| {
+	let result = load_result.and_then(|name|
-	    let module = self.indices.take_module(name).unwrap();
+            if let Some(name) = name {
+	        let module = self.indices.take_module(name).unwrap();
 
-	    // remove previous exports.
+	        // remove previous exports.
-	    self.indices.remove_module(clause_name!("user"), &module);
+	        self.indices.remove_module(clause_name!("user"), &module);
-	    self.indices.use_module(&mut self.code_repo, self.machine_st.flags, &module)?;
+	        self.indices.use_module(&mut self.code_repo, self.machine_st.flags,
+                                        &module)?;
 	        
-	    Ok(self.indices.insert_module(module))
+	        Ok(self.indices.insert_module(module))
-	});	
+	    } else {
+                Ok(())
+            }
+        );	
 	
 	self.code_repo.cached_query = cached_query;
 
@@ -471,25 +477,30 @@ impl Machine {
 	let load_result = match to_src(name) {
 	    ModuleSource::Library(name) =>
 		if !self.indices.modules.contains_key(&name) {
-		    load_library(self, name)
+		    load_library(self, name).map(Some)
 		} else {
-		    Ok(name)
+		    Ok(Some(name))
 		},
-	    ModuleSource::File(name) => load_module_from_file(self, name.as_str())
+	    ModuleSource::File(name) =>
+                load_module_from_file(self, name.as_str())
 	};
 
-	let result = load_result.and_then(|name| {
+	let result = load_result.and_then(|name|
-	    let module = self.indices.take_module(name).unwrap();
+            if let Some(name) = name {
+	        let module = self.indices.take_module(name).unwrap();
 
-	    // remove previous exports.
+	        // remove previous exports.
-	    self.indices.remove_module(clause_name!("user"), &module);
+	        self.indices.remove_module(clause_name!("user"), &module);
-	    self.indices.use_qualified_module(&mut self.code_repo,
+	        self.indices.use_qualified_module(&mut self.code_repo,
-					      self.machine_st.flags,
+					          self.machine_st.flags,
-					      &module,
+					          &module,
-					      &exports)?;
+					          &exports)?;
                 
-	    Ok(self.indices.insert_module(module))
+	        Ok(self.indices.insert_module(module))
-	});
+	    } else {
+                Ok(())
+            }
+        );
 
 	self.code_repo.cached_query = cached_query;