file monitor

examples/basic.py

@@ -6,7 +6,7 @@ class BasicApp(App):
     """A basic app demonstrating CSS"""
 
     def on_load(self):
-        self.bind("t", "toggle('#sidebar', '-active')")
+        self.bind("t", "toggle_class('#sidebar', '-active')")
 
     def on_mount(self):
         """Build layout here."""
@@ -18,4 +18,4 @@ class BasicApp(App):
         )
 
 
-BasicApp.run(log="textual.log", css_file="basic.css", log_verbosity=3)
+BasicApp.run(log="textual.log", css_file="basic.css", watch_css=True)

poetry.lock

@@ -547,7 +547,7 @@ python-versions = "*"
 
 [[package]]
 name = "rich"
-version = "10.15.2"
+version = "10.16.1"
 description = "Render rich text, tables, progress bars, syntax highlighting, markdown and more to the terminal"
 category = "main"
 optional = false
@@ -995,8 +995,8 @@ regex = [
     {file = "regex-2021.8.21.tar.gz", hash = "sha256:faf08b0341828f6a29b8f7dd94d5cf8cc7c39bfc3e67b78514c54b494b66915a"},
 ]
 rich = [
-    {file = "rich-10.15.2-py3-none-any.whl", hash = "sha256:43b2c6ad51f46f6c94992aee546f1c177719f4e05aff8f5ea4d2efae3ebdac89"},
-    {file = "rich-10.15.2.tar.gz", hash = "sha256:1dded089b79dd042b3ab5cd63439a338e16652001f0c16e73acdcf4997ad772d"},
+    {file = "rich-10.16.1-py3-none-any.whl", hash = "sha256:bbe04dd6ac09e4b00d22cb1051aa127beaf6e16c3d8687b026e96d3fca6aad52"},
+    {file = "rich-10.16.1.tar.gz", hash = "sha256:4949e73de321784ef6664ebbc854ac82b20ff60b2865097b93f3b9b41e30da27"},
 ]
 six = [
     {file = "six-1.16.0-py2.py3-none-any.whl", hash = "sha256:8abb2f1d86890a2dfb989f9a77cfcfd3e47c2a354b01111771326f8aa26e0254"},

src/textual/app.py

@@ -25,9 +25,11 @@ from .geometry import Offset, Region
 from . import log
 from ._callback import invoke
 from ._context import active_app
-from .css.stylesheet import Stylesheet, StylesheetParseError
+from .css.stylesheet import Stylesheet, StylesheetParseError, StylesheetError
 from ._event_broker import extract_handler_actions, NoHandler
 from .driver import Driver
+from .file_monitor import FileMonitor
+
 from .layouts.dock import DockLayout, Dock
 from ._linux_driver import LinuxDriver
 from ._types import MessageTarget
@@ -79,6 +81,7 @@ class App(DOMNode):
         title: str = "Textual Application",
         css_file: str | None = None,
         css: str | None = None,
+        watch_css: bool = True,
     ):
         """The Textual Application base class
 
@@ -119,6 +122,11 @@ class App(DOMNode):
         self.stylesheet = Stylesheet()
 
         self.css_file = css_file
+        self.css_monitor = (
+            FileMonitor(css_file, self._on_css_change)
+            if (watch_css and css_file)
+            else None
+        )
         if css is not None:
             self.css = css
 
@@ -148,9 +156,6 @@ class App(DOMNode):
     def css_type(self) -> str:
         return "app"
 
-    def load_css(self, filename: str) -> None:
-        pass
-
     def log(self, *args: Any, verbosity: int = 1, **kwargs) -> None:
         """Write to logs.
 
@@ -214,6 +219,24 @@ class App(DOMNode):
 
         asyncio.run(run_app())
 
+    async def _on_css_change(self) -> None:
+        self.log("CSS changed")
+        self.log("css_file", self.css_file)
+        if self.css_file is not None:
+            stylesheet = Stylesheet()
+            try:
+                self.log("loading", self.css_file)
+                stylesheet.read(self.css_file)
+            except StylesheetError as error:
+                self.log(error)
+                self.console.bell()
+            else:
+                self.log("reseting stylesheet")
+                self.reset_styles()
+                self.stylesheet = stylesheet
+                self.stylesheet.update(self)
+                self.view.refresh(layout=True)
+
     def mount(self, *anon_widgets: Widget, **widgets: Widget) -> None:
         self.register(self.view, *anon_widgets, **widgets)
         self.view.refresh()
@@ -317,6 +340,10 @@ class App(DOMNode):
             self._print_error_renderables()
             return
 
+        if self.css_monitor:
+            self.set_interval(0.5, self.css_monitor)
+            self.log("started", self.css_monitor)
+
         self._running = True
         try:
             load_event = events.Load(sender=self)
@@ -548,6 +575,15 @@ class App(DOMNode):
             return False
         return True
 
+    async def handle_update(self, message: messages.Update) -> None:
+        message.stop()
+        self.app.refresh()
+
+    async def handle_layout(self, message: messages.Layout) -> None:
+        message.stop()
+        await self.view.refresh_layout()
+        self.app.refresh()
+
     async def on_key(self, event: events.Key) -> None:
         await self.press(event.key)
 
@@ -570,7 +606,15 @@ class App(DOMNode):
     async def action_bell(self) -> None:
         self.console.bell()
 
-    async def action_toggle(self, selector: str, class_name: str) -> None:
+    async def action_add_class_(self, selector: str, class_name: str) -> None:
+        self.view.query(selector).add_class(class_name)
+        self.view.refresh(layout=True)
+
+    async def action_remove_class_(self, selector: str, class_name: str) -> None:
+        self.view.query(selector).remove_class(class_name)
+        self.view.refresh(layout=True)
+
+    async def action_toggle_class(self, selector: str, class_name: str) -> None:
         self.view.query(selector).toggle_class(class_name)
         self.view.refresh(layout=True)
 

src/textual/css/model.py

@@ -132,6 +132,7 @@ class RuleSet:
     selector_set: list[SelectorSet] = field(default_factory=list)
     styles: Styles = field(default_factory=Styles)
     errors: list[tuple[Token, str]] = field(default_factory=list)
+    classes: set[str] = field(default_factory=set)
 
     @classmethod
     def _selector_to_css(cls, selectors: list[Selector]) -> str:
@@ -161,3 +162,15 @@ class RuleSet:
         declarations = "\n".join(f"    {line}" for line in self.styles.css_lines)
         css = f"{self.selectors} {{\n{declarations}\n}}"
         return css
+
+    def _post_parse(self) -> None:
+        """Called after the RuleSet is parsed."""
+        # Build a set of the class names that have been updated
+        update = self.classes.update
+        class_type = SelectorType.CLASS
+        for selector_set in self.selector_set:
+            update(
+                selector.name
+                for selector in selector_set.selectors
+                if selector.type == class_type
+            )

src/textual/css/parse.py

@@ -153,6 +153,7 @@ def parse_rule_set(tokens: Iterator[Token], token: Token) -> Iterable[RuleSet]:
     rule_set = RuleSet(
         list(SelectorSet.from_selectors(rule_selectors)), styles_builder.styles, errors
     )
+    rule_set._post_parse()
     yield rule_set
 
 

src/textual/css/styles.py

@@ -83,8 +83,6 @@ class Styles:
     _rule_min_width: Scalar | None = None
     _rule_min_height: Scalar | None = None
 
-    _rule_layout: str | None = None
-
     _rule_dock_group: str | None = None
     _rule_docks: tuple[DockGroup, ...] | None = None
 

src/textual/css/stylesheet.py

@@ -9,9 +9,7 @@ from rich.console import RenderableType
 import rich.repr
 from rich.highlighter import ReprHighlighter
 from rich.panel import Panel
-from rich.syntax import Syntax
-from rich.table import Table
-from rich.text import TextType, Text
+from rich.text import Text
 from rich.console import Group, RenderableType
 
 
@@ -114,8 +112,9 @@ class Stylesheet:
         rule_attributes: dict[str, list[tuple[Specificity4, object]]]
         rule_attributes = defaultdict(list)
 
+        _check_rule = self._check_rule
         for rule in self.rules:
-            for specificity in self._check_rule(rule, node):
+            for specificity in _check_rule(rule, node):
                 for key, rule_specificity, value in rule.styles.extract_rules(
                     specificity
                 ):
@@ -123,8 +122,6 @@ class Stylesheet:
 
         get_first_item = itemgetter(0)
 
-        log(rule_attributes.get("offset"))
-
         node_rules = [
             (name, max(specificity_rules, key=get_first_item)[1])
             for name, specificity_rules in rule_attributes.items()
@@ -132,6 +129,12 @@ class Stylesheet:
 
         node.styles.apply_rules(node_rules)
 
+    def update(self, root: DOMNode) -> None:
+        """Update a node and its children."""
+        apply = self.apply
+        for node in root.walk_children():
+            apply(node)
+
 
 if __name__ == "__main__":
 

src/textual/dom.py

@@ -131,6 +131,14 @@ class DOMNode(MessagePump):
         add_children(tree, self)
         return tree
 
+    def reset_styles(self) -> None:
+        from .widget import Widget
+
+        for node in self.walk_children():
+            node.styles = Styles()
+            if isinstance(node, Widget):
+                node.clear_render_cache()
+
     def add_child(self, node: DOMNode) -> None:
         self.children._append(node)
         node.set_parent(self)
@@ -172,7 +180,7 @@ class DOMNode(MessagePump):
     def toggle_class(self, *class_names: str) -> None:
         """Toggle class names"""
         self._classes.symmetric_difference_update(class_names)
-        self.app.stylesheet.apply(self)
+        self.app.stylesheet.update(self.app)
         self.log(self.styles.css)
 
     def has_psuedo_class(self, *class_names: str) -> bool:

src/textual/file_monitor.py

@@ -0,0 +1,31 @@
+import os
+from typing import Callable
+
+import rich.repr
+
+from ._callback import invoke
+
+
+@rich.repr.auto
+class FileMonitor:
+    def __init__(self, path: str, callback: Callable) -> None:
+        self.path = path
+        self.callback = callback
+        self._modified = self._get_modified()
+
+    def _get_modified(self) -> float:
+        return os.stat(self.path).st_mtime
+
+    def check(self) -> bool:
+        modified = self._get_modified()
+        changed = modified != self._modified
+        self._modified = modified
+        return changed
+
+    async def __call__(self) -> None:
+        if self.check():
+            await self.on_change()
+
+    async def on_change(self) -> None:
+        """Called when file changes."""
+        await invoke(self.callback)

src/textual/widget.py

@@ -84,7 +84,7 @@ class Widget(DOMNode):
     # layout_offset_x: Reactive[float] = Reactive(0.0, layout=True)
     # layout_offset_y: Reactive[float] = Reactive(0.0, layout=True)
 
-    style: Reactive[str | None] = Reactive(None)
+    # style: Reactive[str | None] = Reactive(None)
     padding: Reactive[Spacing | None] = Reactive(None, layout=True)
     margin: Reactive[Spacing | None] = Reactive(None, layout=True)
     border: Reactive[str] = Reactive("none", layout=True)
@@ -97,12 +97,6 @@ class Widget(DOMNode):
     def validate_margin(self, margin: SpacingDimensions) -> Spacing:
         return Spacing.unpack(margin)
 
-    # def validate_layout_offset_x(self, value) -> int:
-    #     return int(value)
-
-    # def validate_layout_offset_y(self, value) -> int:
-    #     return int(value)
-
     def __init_subclass__(cls, can_focus: bool = True) -> None:
         super().__init_subclass__()
         cls.can_focus = can_focus
@@ -285,18 +279,17 @@ class Widget(DOMNode):
         self.refresh()
 
     async def on_idle(self, event: events.Idle) -> None:
-        self.log("Widget.on_idle")
         if self.check_layout():
             self.log("layout required")
             self.render_cache = None
             self.reset_check_repaint()
             self.reset_check_layout()
-            await self.post_message(Layout(self))
+            await self.emit(Layout(self))
         elif self.check_repaint():
             self.log("repaint required")
             self.render_cache = None
             self.reset_check_repaint()
-            await self.post_message(Update(self, self))
+            await self.emit(Update(self, self))
 
     async def focus(self) -> None:
         await self.app.set_focus(self)