Allow list of monitor matchers

CHANGELOG.md

@@ -21,6 +21,7 @@ All notable changes to eww will be listed here, starting at changes since versio
 - Add `substring` function to simplexpr
 - Add `--duration` flag to `eww open`
 - Add support for referring to monitor with `<primary>`
+- Add support for multiple matchers in `monitor` field
 
 ## [0.4.0] (04.09.2022)
 

crates/eww/src/app.rs

@@ -582,6 +582,14 @@ fn get_monitor_geometry(identifier: Option<MonitorIdentifier>) -> Result<gdk::Re
 /// Outside of x11, only [MonitorIdentifier::Numeric] is supported
 pub fn get_monitor_from_display(display: &gdk::Display, identifier: &MonitorIdentifier) -> Option<gdk::Monitor> {
     match identifier {
+        MonitorIdentifier::List(list) => {
+            for ident in list {
+                if let Some(monitor) = get_monitor_from_display(display, ident) {
+                    return Some(monitor);
+                }
+            }
+            None
+        }
         MonitorIdentifier::Primary => display.primary_monitor(),
         MonitorIdentifier::Numeric(num) => display.monitor(*num),
         MonitorIdentifier::Name(name) => {

crates/yuck/src/config/monitor.rs

@@ -5,6 +5,7 @@ use serde::{Deserialize, Serialize};
 /// The type of the identifier used to select a monitor
 #[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
 pub enum MonitorIdentifier {
+    List(Vec<MonitorIdentifier>),
     Numeric(i32),
     Name(String),
     Primary,
@@ -19,6 +20,7 @@ impl MonitorIdentifier {
 impl fmt::Display for MonitorIdentifier {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         match self {
+            Self::List(l) => write!(f, "[{}]", l.iter().map(|x| x.to_string()).collect::<Vec<_>>().join(" ")),
             Self::Numeric(n) => write!(f, "{}", n),
             Self::Name(n) => write!(f, "{}", n),
             Self::Primary => write!(f, "<primary>"),

crates/yuck/src/config/window_definition.rs

@@ -1,4 +1,4 @@
-use std::fmt::Display;
+use std::{fmt::Display, str::FromStr};
 
 use crate::{
     config::monitor::MonitorIdentifier,
@@ -24,13 +24,22 @@ pub struct WindowDefinition {
     pub backend_options: BackendWindowOptions,
 }
 
+impl FromAst for MonitorIdentifier {
+    fn from_ast(x: Ast) -> DiagResult<Self> {
+        match x {
+            Ast::Array(_, x) => Ok(Self::List(x.into_iter().map(MonitorIdentifier::from_ast).collect::<DiagResult<_>>()?)),
+            other => Ok(Self::from_str(&String::from_ast(other)?).unwrap()),
+        }
+    }
+}
+
 impl FromAstElementContent for WindowDefinition {
     const ELEMENT_NAME: &'static str = "defwindow";
 
     fn from_tail<I: Iterator<Item = Ast>>(_span: Span, mut iter: AstIterator<I>) -> DiagResult<Self> {
         let (_, name) = iter.expect_symbol()?;
         let mut attrs = iter.expect_key_values()?;
-        let monitor = attrs.primitive_optional("monitor")?;
+        let monitor = attrs.ast_optional::<MonitorIdentifier>("monitor")?;
         let resizable = attrs.primitive_optional("resizable")?.unwrap_or(true);
         let stacking = attrs.primitive_optional("stacking")?.unwrap_or(WindowStacking::Foreground);
         let geometry = attrs.ast_optional("geometry")?;

crates/yuck/src/parser/ast.rs

@@ -71,6 +71,8 @@ impl Ast {
 
     as_func!(AstType::List, as_list as_list_ref<Vec<Ast>> = Ast::List(_, x) => x);
 
+    as_func!(AstType::Array, as_array as_array_ref<Vec<Ast>> = Ast::Array(_, x) => x);
+
     pub fn expr_type(&self) -> AstType {
         match self {
             Ast::List(..) => AstType::List,

docs/src/configuration.md

@@ -50,10 +50,20 @@ You can now open your first window by running `eww open example`! Glorious!
 
 |   Property | Description                                                  |
 | ---------: | ------------------------------------------------------------ |
-|  `monitor` | Which monitor this window should be displayed on. Can be either a number (X11 and Wayland) or an output name (X11 only). |
+|  `monitor` | Which monitor this window should be displayed on. See below for details.|
 | `geometry` | Geometry of the window.  |
 
 
+**`monitor`-property**
+
+This field can be:
+
+- the string `<primary>`, in which case eww tries to identify the primary display (which may fail, especially on wayland)
+- an integer, declaring the monitor index
+- the name of the monitor
+- an array of monitor matchers, such as: `["<primary>" "HDMI-A-1" "PHL 345B1C" 0]`. Eww will try to find a match in order, allowing you to specify fallbacks.
+
+
 **`geometry`-properties**
 
 | Property          | Description |