diff --git a/src/geom/mod.rs b/src/geom/mod.rs
index 6161774b9..225eb10d2 100644
--- a/src/geom/mod.rs
+++ b/src/geom/mod.rs
@@ -131,6 +131,6 @@ pub trait Numeric:
 }
 
 /// Round a float to two decimal places.
-fn round_2(value: f64) -> f64 {
+pub fn round_2(value: f64) -> f64 {
     (value * 100.0).round() / 100.0
 }
diff --git a/src/ide/analyze.rs b/src/ide/analyze.rs
index 65d9ded87..12576e537 100644
--- a/src/ide/analyze.rs
+++ b/src/ide/analyze.rs
@@ -7,6 +7,22 @@ use crate::World;
 /// Try to determine a set of possible values for an expression.
 pub fn analyze(world: &(dyn World + 'static), node: &LinkedNode) -> Vec<Value> {
     match node.cast::<ast::Expr>() {
+        Some(ast::Expr::None(_)) => vec![Value::None],
+        Some(ast::Expr::Auto(_)) => vec![Value::Auto],
+        Some(ast::Expr::Bool(v)) => vec![Value::Bool(v.get())],
+        Some(ast::Expr::Int(v)) => vec![Value::Int(v.get())],
+        Some(ast::Expr::Float(v)) => vec![Value::Float(v.get())],
+        Some(ast::Expr::Numeric(v)) => vec![Value::numeric(v.get())],
+        Some(ast::Expr::Str(v)) => vec![Value::Str(v.get().into())],
+
+        Some(ast::Expr::FieldAccess(access)) => {
+            let Some(child) = node.children().next() else { return vec![] };
+            analyze(world, &child)
+                .into_iter()
+                .filter_map(|target| target.field(&access.field()).ok())
+                .collect()
+        }
+
         Some(ast::Expr::Ident(_) | ast::Expr::MathIdent(_) | ast::Expr::FuncCall(_)) => {
             if let Some(parent) = node.parent() {
                 if parent.kind() == SyntaxKind::FieldAccess && node.index() > 0 {
@@ -19,22 +35,9 @@ pub fn analyze(world: &(dyn World + 'static), node: &LinkedNode) -> Vec<Value> {
             let route = Route::default();
             let mut tracer = Tracer::new(Some(span));
             eval(world.track(), route.track(), tracer.track_mut(), source).ok();
-            return tracer.finish();
+            tracer.finish()
         }
 
-        Some(ast::Expr::Str(s)) => return vec![Value::Str(s.get().into())],
-
-        Some(ast::Expr::FieldAccess(access)) => {
-            if let Some(child) = node.children().next() {
-                return analyze(world, &child)
-                    .into_iter()
-                    .filter_map(|target| target.field(&access.field()).ok())
-                    .collect();
-            }
-        }
-
-        _ => {}
+        _ => vec![],
     }
-
-    vec![]
 }
diff --git a/src/ide/tooltip.rs b/src/ide/tooltip.rs
index 202efd8e1..701c56225 100644
--- a/src/ide/tooltip.rs
+++ b/src/ide/tooltip.rs
@@ -2,6 +2,7 @@ use if_chain::if_chain;
 use unicode_segmentation::UnicodeSegmentation;
 
 use super::{analyze, plain_docs_sentence, summarize_font_family};
+use crate::geom::{round_2, Length, Numeric};
 use crate::model::{CastInfo, Tracer, Value};
 use crate::syntax::ast;
 use crate::syntax::{LinkedNode, Source, SyntaxKind};
@@ -22,15 +23,23 @@ pub fn tooltip(
 
 /// Tooltip for a hovered expression.
 fn expr_tooltip(world: &(dyn World + 'static), leaf: &LinkedNode) -> Option<String> {
-    if !leaf.is::<ast::Expr>() {
-        return None;
-    }
-
+    let expr = leaf.cast::<ast::Expr>()?;
     let values = analyze(world, leaf);
+
     if let [value] = values.as_slice() {
         if let Some(docs) = value.docs() {
             return Some(plain_docs_sentence(docs));
         }
+
+        if let &Value::Length(length) = value {
+            if let Some(tooltip) = length_tooltip(length) {
+                return Some(tooltip);
+            }
+        }
+    }
+
+    if expr.is_literal() {
+        return None;
     }
 
     let mut tooltip = String::new();
@@ -61,6 +70,19 @@ fn expr_tooltip(world: &(dyn World + 'static), leaf: &LinkedNode) -> Option<Stri
     (!tooltip.is_empty()).then(|| tooltip)
 }
 
+/// Tooltip text for a hovered length.
+fn length_tooltip(length: Length) -> Option<String> {
+    length.em.is_zero().then(|| {
+        format!(
+            "{}pt = {}mm = {}cm = {}in",
+            round_2(length.abs.to_pt()),
+            round_2(length.abs.to_mm()),
+            round_2(length.abs.to_cm()),
+            round_2(length.abs.to_inches())
+        )
+    })
+}
+
 /// Tooltips for components of a named parameter.
 fn named_param_tooltip(
     world: &(dyn World + 'static),
diff --git a/src/model/eval.rs b/src/model/eval.rs
index d0751a1f6..96e7317df 100644
--- a/src/model/eval.rs
+++ b/src/model/eval.rs
@@ -15,7 +15,6 @@ use super::{
 use crate::diag::{
     bail, error, At, SourceError, SourceResult, StrResult, Trace, Tracepoint,
 };
-use crate::geom::{Abs, Angle, Em, Fr, Ratio};
 use crate::syntax::ast::AstNode;
 use crate::syntax::{ast, Source, SourceId, Span, Spanned, SyntaxKind, SyntaxNode};
 use crate::util::PathExt;
@@ -660,14 +659,7 @@ impl Eval for ast::Numeric {
     type Output = Value;
 
     fn eval(&self, _: &mut Vm) -> SourceResult<Self::Output> {
-        let (v, unit) = self.get();
-        Ok(match unit {
-            ast::Unit::Length(unit) => Abs::with_unit(v, unit).into(),
-            ast::Unit::Angle(unit) => Angle::with_unit(v, unit).into(),
-            ast::Unit::Em => Em::new(v).into(),
-            ast::Unit::Fr => Fr::new(v).into(),
-            ast::Unit::Percent => Ratio::new(v / 100.0).into(),
-        })
+        Ok(Value::numeric(self.get()))
     }
 }
 
diff --git a/src/model/value.rs b/src/model/value.rs
index ea17349e1..b860a3f66 100644
--- a/src/model/value.rs
+++ b/src/model/value.rs
@@ -12,7 +12,7 @@ use super::{
 };
 use crate::diag::StrResult;
 use crate::geom::{Abs, Angle, Color, Em, Fr, Length, Ratio, Rel, RgbaColor};
-use crate::syntax::Span;
+use crate::syntax::{ast, Span};
 use crate::util::{format_eco, EcoString};
 
 /// A computational value.
@@ -71,6 +71,18 @@ impl Value {
         Self::Dyn(Dynamic::new(any))
     }
 
+    /// Create a numeric value from a number with a unit.
+    pub fn numeric(pair: (f64, ast::Unit)) -> Self {
+        let (v, unit) = pair;
+        match unit {
+            ast::Unit::Length(unit) => Abs::with_unit(v, unit).into(),
+            ast::Unit::Angle(unit) => Angle::with_unit(v, unit).into(),
+            ast::Unit::Em => Em::new(v).into(),
+            ast::Unit::Fr => Fr::new(v).into(),
+            ast::Unit::Percent => Ratio::new(v / 100.0).into(),
+        }
+    }
+
     /// The name of the stored value's type.
     pub fn type_name(&self) -> &'static str {
         match self {
diff --git a/src/syntax/ast.rs b/src/syntax/ast.rs
index 78d895fff..08def5338 100644
--- a/src/syntax/ast.rs
+++ b/src/syntax/ast.rs
@@ -345,6 +345,20 @@ impl Expr {
             _ => false,
         }
     }
+
+    /// Is this a literal?
+    pub fn is_literal(&self) -> bool {
+        match self {
+            Self::None(_) => true,
+            Self::Auto(_) => true,
+            Self::Bool(_) => true,
+            Self::Int(_) => true,
+            Self::Float(_) => true,
+            Self::Numeric(_) => true,
+            Self::Str(_) => true,
+            _ => false,
+        }
+    }
 }
 
 impl Default for Expr {
diff --git a/src/syntax/lexer.rs b/src/syntax/lexer.rs
index cbddabb76..555ced849 100644
--- a/src/syntax/lexer.rs
+++ b/src/syntax/lexer.rs
@@ -499,7 +499,11 @@ impl Lexer<'_> {
 
         // Read the fractional part if not already done.
         // Make sure not to confuse a range for the decimal separator.
-        if c != '.' && !self.s.at("..") && self.s.eat_if('.') {
+        if c != '.'
+            && !self.s.at("..")
+            && !self.s.scout(1).map_or(false, is_id_start)
+            && self.s.eat_if('.')
+        {
             self.s.eat_while(char::is_ascii_digit);
         }