Make text and space nodes unselectable

library/src/lib.rs

@@ -24,7 +24,6 @@ fn scope() -> Scope {
     let mut std = Scope::new();
 
     // Text.
-    std.def_node::<text::SpaceNode>("space");
     std.def_node::<text::LinebreakNode>("linebreak");
     std.def_node::<text::SmartQuoteNode>("smartquote");
     std.def_node::<text::TextNode>("text");

src/model/cast.rs

@@ -185,7 +185,7 @@ dynamic! {
     Selector: "selector",
     Value::Str(text) => Self::text(&text),
     Value::Label(label) => Self::Label(label),
-    Value::Func(func) => Self::Node(func.node()?, None),
+    Value::Func(func) => func.select(None)?,
     @regex: Regex => Self::Regex(regex.clone()),
 }
 

src/model/eval.rs

@@ -932,10 +932,9 @@ impl Eval for ast::SetRule {
         }
 
         let target = self.target();
-        let span = target.span();
-        let target = target.eval(vm)?.cast::<Func>().at(span)?;
+        let target = target.eval(vm)?.cast::<Func>().at(target.span())?;
         let args = self.args().eval(vm)?;
-        target.set(args, span)
+        target.set(args)
     }
 }
 

src/model/func.rs

@@ -5,11 +5,12 @@ use std::sync::Arc;
 use comemo::{Track, Tracked};
 
 use super::{
-    Args, Eval, Flow, Node, NodeId, Route, Scope, Scopes, Selector, StyleMap, Value, Vm,
+    Args, Dict, Eval, Flow, Node, NodeId, Route, Scope, Scopes, Selector, StyleMap,
+    Value, Vm,
 };
 use crate::diag::{bail, SourceResult, StrResult};
 use crate::syntax::ast::{self, AstNode, Expr};
-use crate::syntax::{SourceId, Span, SyntaxNode};
+use crate::syntax::{SourceId, SyntaxNode};
 use crate::util::EcoString;
 use crate::World;
 
@@ -108,33 +109,35 @@ impl Func {
         Self(Arc::new(Repr::With(self, args)))
     }
 
-    /// Execute the function's set rule and return the resulting style map.
-    pub fn set(&self, mut args: Args, span: Span) -> SourceResult<StyleMap> {
-        let Repr::Native(Native { set: Some(set), .. }) = self.0.as_ref() else {
-            bail!(span, "this function cannot be customized with set");
-        };
-
-        let styles = set(&mut args)?;
-        args.finish()?;
-        Ok(styles)
-    }
-
-    /// The id of the node to customize with this function's show rule.
-    pub fn node(&self) -> StrResult<NodeId> {
-        match self.0.as_ref() {
-            Repr::Native(Native { node: Some(id), .. }) => Ok(*id),
-            _ => Err("this function cannot be customized with show")?,
-        }
-    }
-
     /// Create a selector for this function's node type, filtering by node's
     /// whose [fields](super::Content::field) match the given arguments.
     pub fn where_(self, args: &mut Args) -> StrResult<Selector> {
+        let fields = args.to_named();
+        args.items.retain(|arg| arg.name.is_none());
+        self.select(Some(fields))
+    }
+
+    /// Execute the function's set rule and return the resulting style map.
+    pub fn set(&self, mut args: Args) -> SourceResult<StyleMap> {
+        Ok(match self.0.as_ref() {
+            Repr::Native(Native { set: Some(set), .. }) => {
+                let styles = set(&mut args)?;
+                args.finish()?;
+                styles
+            }
+            _ => StyleMap::new(),
+        })
+    }
+
+    /// Create a selector for this function's node type.
+    pub fn select(&self, fields: Option<Dict>) -> StrResult<Selector> {
         match self.0.as_ref() {
-            Repr::Native(Native { node: Some(id), .. }) => {
-                let named = args.to_named();
-                args.items.retain(|arg| arg.name.is_none());
-                Ok(Selector::Node(*id, Some(named)))
+            &Repr::Native(Native { node: Some(id), .. }) => {
+                if id == item!(text_id) {
+                    Err("to select text, please use a string or regex instead")?;
+                }
+
+                Ok(Selector::Node(id, fields))
             }
             _ => Err("this function is not selectable")?,
         }

tests/typ/style/show-node.typ

@@ -83,9 +83,13 @@ Another text.
 = Heading
 
 ---
-// Error: 7-12 this function cannot be customized with show
+// Error: 7-12 this function is not selectable
 #show upper: it => {}
 
+---
+// Error: 7-11 to select text, please use a string or regex instead
+#show text: it => {}
+
 ---
 // Error: 16-20 expected content or function, found integer
 #show heading: 1234