Jump to source and preview

7 files changed, 154 insertions, 52 deletions

diff --git a/src/doc.rs b/src/doc.rs
index 67e13bc8..76a45606 100644
--- a/src/doc.rs
+++ b/src/doc.rs
@@ -15,6 +15,7 @@ use crate::geom::{
 };
 use crate::image::Image;
 use crate::model::{node, Content, Fold, StableId, StyleChain};
+use crate::syntax::Span;
 
 /// A finished document with metadata and page frames.
 #[derive(Debug, Default, Clone, Hash)]
@@ -119,8 +120,8 @@ impl Frame {
         let mut text = EcoString::new();
         for (_, element) in self.elements() {
             match element {
-                Element::Text(content) => {
-                    for glyph in &content.glyphs {
+                Element::Text(element) => {
+                    for glyph in &element.glyphs {
                         text.push(glyph.c);
                     }
                 }
@@ -499,6 +500,10 @@ pub struct Glyph {
     pub x_offset: Em,
     /// The first character of the glyph's cluster.
     pub c: char,
+    /// The source code location of the text.
+    pub span: Span,
+    /// The offset within the spanned text.
+    pub offset: u16,
 }
 
 /// An identifier for a natural language.
diff --git a/src/eval/func.rs b/src/eval/func.rs
index 26854240..a5fa6fa1 100644
--- a/src/eval/func.rs
+++ b/src/eval/func.rs
@@ -62,9 +62,11 @@ impl Func {
         self.1
     }
 
-    /// Attach a span to the function.
+    /// Attach a span to this function if it doesn't already have one.
     pub fn spanned(mut self, span: Span) -> Self {
-        self.1 = span;
+        if self.1.is_detached() {
+            self.1 = span;
+        }
         self
     }
 
diff --git a/src/ide/jump.rs b/src/ide/jump.rs
new file mode 100644
index 00000000..1a96fbbe
--- /dev/null
+++ b/src/ide/jump.rs
@@ -0,0 +1,93 @@
+use std::num::NonZeroUsize;
+
+use crate::doc::{Element, Frame, Location};
+use crate::geom::Point;
+use crate::syntax::{LinkedNode, Source, Span, SyntaxKind};
+use crate::World;
+
+/// Find the source file and byte offset for a click position.
+pub fn jump_to_source<'a>(
+    world: &'a dyn World,
+    frame: &Frame,
+    click: Point,
+) -> Option<(&'a Source, usize)> {
+    for (mut pos, element) in frame.elements() {
+        if let Element::Text(text) = element {
+            for glyph in &text.glyphs {
+                if glyph.span.is_detached() {
+                    continue;
+                }
+
+                let width = glyph.x_advance.at(text.size);
+                if pos.x <= click.x
+                    && pos.x + width >= click.x
+                    && pos.y >= click.y
+                    && pos.y - text.size <= click.y
+                {
+                    let source = world.source(glyph.span.source());
+                    let node = source.find(glyph.span);
+                    let pos = if node.kind() == SyntaxKind::Text {
+                        let range = node.range();
+                        (range.start + usize::from(glyph.offset)).min(range.end)
+                    } else {
+                        node.offset()
+                    };
+                    return Some((source, pos));
+                }
+
+                pos.x += width;
+            }
+        }
+
+        if let Element::Group(group) = element {
+            if let Some(span) = jump_to_source(world, &group.frame, click - pos) {
+                return Some(span);
+            }
+        }
+    }
+
+    None
+}
+
+/// Find the output location for a cursor position.
+pub fn jump_to_preview(
+    frames: &[Frame],
+    source: &Source,
+    cursor: usize,
+) -> Option<Location> {
+    let node = LinkedNode::new(source.root()).leaf_at(cursor)?;
+    if node.kind() != SyntaxKind::Text {
+        return None;
+    }
+
+    let span = node.span();
+    for (i, frame) in frames.iter().enumerate() {
+        if let Some(pos) = find_in_frame(frame, span) {
+            return Some(Location { page: NonZeroUsize::new(i + 1).unwrap(), pos });
+        }
+    }
+
+    None
+}
+
+/// Find the position of a span in a frame.
+fn find_in_frame(frame: &Frame, span: Span) -> Option<Point> {
+    for (mut pos, element) in frame.elements() {
+        if let Element::Text(text) = element {
+            for glyph in &text.glyphs {
+                if glyph.span == span {
+                    return Some(pos);
+                }
+                pos.x += glyph.x_advance.at(text.size);
+            }
+        }
+
+        if let Element::Group(group) = element {
+            if let Some(point) = find_in_frame(&group.frame, span) {
+                return Some(point + pos);
+            }
+        }
+    }
+
+    None
+}
diff --git a/src/ide/mod.rs b/src/ide/mod.rs
index 4999da52..bee959cd 100644
--- a/src/ide/mod.rs
+++ b/src/ide/mod.rs
@@ -3,10 +3,12 @@
 mod analyze;
 mod complete;
 mod highlight;
+mod jump;
 mod tooltip;
 
 pub use self::complete::*;
 pub use self::highlight::*;
+pub use self::jump::*;
 pub use self::tooltip::*;
 
 use std::fmt::Write;
diff --git a/src/model/content.rs b/src/model/content.rs
index 012ad05f..071a5862 100644
--- a/src/model/content.rs
+++ b/src/model/content.rs
@@ -106,9 +106,11 @@ impl Content {
         self.span
     }
 
-    /// Attach a span to the content.
+    /// Attach a span to the content if it doesn't already have one.
     pub fn spanned(mut self, span: Span) -> Self {
-        self.span = span;
+        if self.span.is_detached() {
+            self.span = span;
+        }
         self
     }
 
diff --git a/src/syntax/node.rs b/src/syntax/node.rs
index 392633f6..afbebe97 100644
--- a/src/syntax/node.rs
+++ b/src/syntax/node.rs
@@ -204,14 +204,6 @@ impl SyntaxNode {
         Ok(())
     }
 
-    /// If the span points into this node, convert it to a byte range.
-    pub(super) fn range(&self, span: Span, offset: usize) -> Option<Range<usize>> {
-        match &self.0 {
-            Repr::Inner(inner) => inner.range(span, offset),
-            _ => (self.span() == span).then(|| offset..offset + self.len()),
-        }
-    }
-
     /// Whether this is a leaf node.
     pub(super) fn is_leaf(&self) -> bool {
         matches!(self.0, Repr::Leaf(_))
@@ -429,40 +421,6 @@ impl InnerNode {
         Ok(())
     }
 
-    /// If the span points into this node, convert it to a byte range.
-    fn range(&self, span: Span, mut offset: usize) -> Option<Range<usize>> {
-        // Check whether we found it.
-        if span == self.span {
-            return Some(offset..offset + self.len);
-        }
-
-        // The parent of a subtree has a smaller span number than all of its
-        // descendants. Therefore, we can bail out early if the target span's
-        // number is smaller than our number.
-        if span.number() < self.span.number() {
-            return None;
-        }
-
-        let mut children = self.children.iter().peekable();
-        while let Some(child) = children.next() {
-            // Every node in this child's subtree has a smaller span number than
-            // the next sibling. Therefore we only need to recurse if the next
-            // sibling's span number is larger than the target span's number.
-            if children
-                .peek()
-                .map_or(true, |next| next.span().number() > span.number())
-            {
-                if let Some(range) = child.range(span, offset) {
-                    return Some(range);
-                }
-            }
-
-            offset += child.len();
-        }
-
-        None
-    }
-
     /// Replaces a range of children with a replacement.
     ///
     /// May have mutated the children if it returns `Err(_)`.
@@ -669,6 +627,39 @@ impl<'a> LinkedNode<'a> {
             back: self.offset + self.len(),
         }
     }
+
+    /// Find a descendant with the given span.
+    pub fn find(&self, span: Span) -> Option<LinkedNode<'a>> {
+        if self.span() == span {
+            return Some(self.clone());
+        }
+
+        if let Repr::Inner(inner) = &self.0 {
+            // The parent of a subtree has a smaller span number than all of its
+            // descendants. Therefore, we can bail out early if the target span's
+            // number is smaller than our number.
+            if span.number() < inner.span.number() {
+                return None;
+            }
+
+            let mut children = self.children().peekable();
+            while let Some(child) = children.next() {
+                // Every node in this child's subtree has a smaller span number than
+                // the next sibling. Therefore we only need to recurse if the next
+                // sibling's span number is larger than the target span's number.
+                if children
+                    .peek()
+                    .map_or(true, |next| next.span().number() > span.number())
+                {
+                    if let Some(found) = child.find(span) {
+                        return Some(found);
+                    }
+                }
+            }
+        }
+
+        None
+    }
 }
 
 /// Access to parents and siblings.
diff --git a/src/syntax/source.rs b/src/syntax/source.rs
index f00d779b..607a2603 100644
--- a/src/syntax/source.rs
+++ b/src/syntax/source.rs
@@ -9,7 +9,7 @@ use comemo::Prehashed;
 use unscanny::Scanner;
 
 use super::ast::Markup;
-use super::{is_newline, parse, reparse, Span, SyntaxNode};
+use super::{is_newline, parse, reparse, LinkedNode, Span, SyntaxNode};
 use crate::diag::SourceResult;
 use crate::util::{PathExt, StrExt};
 
@@ -149,13 +149,20 @@ impl Source {
         self.lines.len()
     }
 
+    /// Find the node with the given span.
+    ///
+    /// Panics if the span does not point into this source file.
+    pub fn find(&self, span: Span) -> LinkedNode<'_> {
+        LinkedNode::new(&self.root)
+            .find(span)
+            .expect("span does not point into this source file")
+    }
+
     /// Map a span that points into this source file to a byte range.
     ///
     /// Panics if the span does not point into this source file.
     pub fn range(&self, span: Span) -> Range<usize> {
-        self.root
-            .range(span, 0)
-            .expect("span does not point into this source file")
+        self.find(span).range()
     }
 
     /// Return the index of the UTF-16 code unit at the byte index.