feat: suspend on ctrl+z

... unless the WithoutJobControl() option is specified.

commands.go

@@ -170,3 +170,18 @@ func Sequentially(cmds ...Cmd) Cmd {
 		return nil
 	}
 }
+
+// Suspend causes the process to suspend itself.  By default, this
+// command is automatically sent when Ctrl+Z is pressed. When the
+// WithoutJobControl program option is specified, Ctrl+Z becomes
+// controllable by the pgoram and the program can choose to send the
+// Suspend command upon a different key input or some other event.
+func Suspend() Cmd {
+	return func() Msg {
+		return suspendMsg{}
+	}
+}
+
+// suspendMsg is the internal message used to suspend the process.
+// You can send a suspendMsg with Suspend.
+type suspendMsg struct{}

exec.go

@@ -127,3 +127,22 @@ func (p *Program) exec(c ExecCommand, fn ExecCallback) {
 		go p.Send(fn(err))
 	}
 }
+
+type fnAsCommand func()
+
+var _ ExecCommand = fnAsCommand(nil)
+
+// Run is part of the tea.ExecCommand interface.
+func (d fnAsCommand) Run() error {
+	d()
+	return nil
+}
+
+// SetStdin is part of the tea.ExecCommand interface.
+func (d fnAsCommand) SetStdin(io.Reader) {}
+
+// SetStdout is part of the tea.ExecCommand interface.
+func (d fnAsCommand) SetStdout(io.Writer) {}
+
+// SetStderr is part of the tea.ExecCommand interface.
+func (d fnAsCommand) SetStderr(io.Writer) {}

options.go

@@ -133,3 +133,12 @@ func WithANSICompressor() ProgramOption {
 		p.startupOptions |= withANSICompressor
 	}
 }
+
+// WithoutJobControl disables support for suspending the process when
+// Ctrl+Z is pressed. By default, Ctrl+Z causes SIGTSTPT to be
+// emitted, to support job control in the surrounding unix shell.
+func WithoutJobControl() ProgramOption {
+	return func(p *Program) {
+		p.disableSuspendOnCtrlZ = true
+	}
+}

tea.go

@@ -101,6 +101,10 @@ type Program struct {
 	// is on by default.
 	CatchPanics bool
 
+	// disableSuspendOnCtrlZ removes direct bubbletea support for Ctrl+Z
+	// (suspend process).
+	disableSuspendOnCtrlZ bool
+
 	ignoreSignals bool
 
 	killc chan bool
@@ -413,6 +417,26 @@ func (p *Program) StartReturningModel() (Model, error) {
 						}
 					}
 				}()
+
+			case KeyMsg:
+				if !p.disableSuspendOnCtrlZ && msg.Type == KeyCtrlZ && !msg.Alt {
+					cmds <- Suspend()
+					continue
+				}
+
+			case suspendMsg:
+				if sigTermStop != 0 {
+					// NB: this blocks.
+					cmds <- Exec(fnAsCommand(func() {
+						pr, err := os.FindProcess(os.Getpid())
+						if err != nil {
+							// No-op.
+							return
+						}
+						_ = pr.Signal(sigTermStop)
+					}), nil)
+				}
+				continue
 			}
 
 			// Process internal messages for the renderer.