Implement sys.displayhook

src/shell.rs

@@ -6,7 +6,7 @@ use rustpython_vm::readline::{Readline, ReadlineResult};
 use rustpython_vm::{
     exceptions::{print_exception, PyBaseExceptionRef},
     obj::objtype,
-    pyobject::{ItemProtocol, PyResult},
+    pyobject::PyResult,
     scope::Scope,
     VirtualMachine,
 };
@@ -19,19 +19,10 @@ enum ShellExecResult {
 
 fn shell_exec(vm: &VirtualMachine, source: &str, scope: Scope) -> ShellExecResult {
     match vm.compile(source, compile::Mode::Single, "<stdin>".to_owned()) {
-        Ok(code) => {
-            match vm.run_code_obj(code, scope.clone()) {
-                Ok(value) => {
-                    // Save non-None values as "_"
-                    if !vm.is_none(&value) {
-                        let key = "_";
-                        scope.globals.set_item(key, value, vm).unwrap();
-                    }
-                    ShellExecResult::Ok
-                }
-                Err(err) => ShellExecResult::PyErr(err),
-            }
-        }
+        Ok(code) => match vm.run_code_obj(code, scope.clone()) {
+            Ok(_val) => ShellExecResult::Ok,
+            Err(err) => ShellExecResult::PyErr(err),
+        },
         Err(CompileError {
             error: CompileErrorType::Parse(ParseErrorType::EOF),
             ..

vm/src/builtins.rs

@@ -618,7 +618,7 @@ pub fn builtin_exit(exit_code_arg: OptionalArg<PyObjectRef>, vm: &VirtualMachine
     Err(vm.new_exception(vm.ctx.exceptions.system_exit.clone(), vec![code]))
 }
 
-#[derive(Debug, FromArgs)]
+#[derive(Debug, Default, FromArgs)]
 pub struct PrintOptions {
     #[pyarg(keyword_only, default = "None")]
     sep: Option<PyStringRef>,

vm/src/frame.rs

@@ -647,13 +647,10 @@ impl ExecutingFrame<'_> {
             bytecode::Instruction::Continue => self.unwind_blocks(vm, UnwindReason::Continue),
             bytecode::Instruction::PrintExpr => {
                 let expr = self.pop_value();
-                if !expr.is(&vm.get_none()) {
-                    let repr = vm.to_repr(&expr)?;
-                    // TODO: implement sys.displayhook
-                    if let Ok(ref print) = vm.get_attribute(vm.builtins.clone(), "print") {
-                        vm.invoke(print, vec![repr.into_object()])?;
-                    }
-                }
+
+                let displayhook = vm.get_attribute(vm.sys_module.clone(), "displayhook")?;
+                vm.invoke(&displayhook, vec![expr])?;
+
                 Ok(None)
             }
             bytecode::Instruction::LoadBuildClass => {

vm/src/obj/objbool.rs

@@ -187,7 +187,7 @@ pub fn get_py_int(obj: &PyObjectRef) -> &PyInt {
     &obj.payload::<PyInt>().unwrap()
 }
 
-#[derive(Debug, Copy, Clone, PartialEq)]
+#[derive(Debug, Default, Copy, Clone, PartialEq)]
 pub struct IntoPyBool {
     value: bool,
 }

vm/src/sysmodule.rs

@@ -1,8 +1,9 @@
 use std::sync::Arc;
 use std::{env, mem};
 
+use crate::builtins;
 use crate::frame::FrameRef;
-use crate::function::OptionalArg;
+use crate::function::{Args, OptionalArg, PyFuncArgs};
 use crate::obj::objstr::PyStringRef;
 use crate::pyhash::PyHashInfo;
 use crate::pyobject::{
@@ -202,6 +203,24 @@ fn sys_exit(code: OptionalArg<PyObjectRef>, vm: &VirtualMachine) -> PyResult {
     Err(vm.new_exception(vm.ctx.exceptions.system_exit.clone(), vec![code]))
 }
 
+fn sys_audit(_args: PyFuncArgs) {
+    // TODO: sys.audit implementation
+}
+
+fn sys_displayhook(obj: PyObjectRef, vm: &VirtualMachine) -> PyResult<()> {
+    // Save non-None values as "_"
+    if vm.is_none(&obj) {
+        return Ok(());
+    }
+    // set to none to avoid recursion while printing
+    vm.set_attr(&vm.builtins, "_", vm.get_none())?;
+    // TODO: catch encoding errors
+    let repr = vm.to_repr(&obj)?.into_object();
+    builtins::builtin_print(Args::new(vec![repr]), Default::default(), vm)?;
+    vm.set_attr(&vm.builtins, "_", obj)?;
+    Ok(())
+}
+
 pub fn make_module(vm: &VirtualMachine, module: PyObjectRef, builtins: PyObjectRef) {
     let ctx = &vm.ctx;
 
@@ -394,6 +413,9 @@ settrace() -- set the global debug tracing function
       "base_exec_prefix" => ctx.new_str(base_exec_prefix.to_owned()),
       "exit" => ctx.new_function(sys_exit),
       "abiflags" => ctx.new_str("".to_owned()),
+      "audit" => ctx.new_function(sys_audit),
+      "displayhook" => ctx.new_function(sys_displayhook),
+      "__displayhook__" => ctx.new_function(sys_displayhook),
     });
 
     modules.set_item("sys", module.clone(), vm).unwrap();