refactor: Dedupe backend helpers and polish signature caps, markers, clap help

crates/ctx-exec/src/lib.rs

@@ -433,7 +433,11 @@ impl StreamCompressor {
 }
 
 fn omit_marker(n: usize) -> String {
-    format!("... [{n} lines omitted]")
+    if n == 1 {
+        "... [1 line omitted]".to_string()
+    } else {
+        format!("... [{n} lines omitted]")
+    }
 }
 
 fn saved_pct(original: usize, compressed: usize) -> u32 {

crates/ctx-exec/tests/compress_test.rs

@@ -556,3 +556,20 @@ fn stream_compressor_with_no_pushes_is_empty() {
     assert_eq!(result.stats.saved_percent, 0);
     assert!(!result.stats.compression_ineffective());
 }
+
+#[test]
+fn singular_omission_run_says_line_not_lines() {
+    // One line between the head and tail windows: the marker must read
+    // "[1 line omitted]", not "[1 lines omitted]".
+    let options = CompressOptions {
+        head_lines: 1,
+        tail_lines: 1,
+        collapse_threshold: 2,
+        ..opts()
+    };
+    let result = compress("a\nb\nc\n", &options).unwrap();
+    assert_eq!(
+        String::from_utf8_lossy(&result.text),
+        "a\n... [1 line omitted]\nc"
+    );
+}

crates/ctx-symbol/src/lang/c.rs

@@ -75,19 +75,6 @@ impl Language for CLang {
             .map(|s| s.trim().to_string())
     }
 
-    fn signature(&self, node: &tree_sitter::Node, source: &str) -> String {
-        let start = node.start_byte();
-        let text = source
-            .get(start..node.end_byte().min(source.len()))
-            .unwrap_or("…");
-        let line = text.split('\n').next().unwrap_or("").trim();
-        if line.is_empty() {
-            "…".to_string()
-        } else {
-            line.to_string()
-        }
-    }
-
     fn has_doc_comment(&self, _node: &tree_sitter::Node) -> bool {
         true
     }

crates/ctx-symbol/src/lang/cpp.rs

@@ -81,19 +81,6 @@ impl Language for CppLang {
             .map(|s| s.trim().to_string())
     }
 
-    fn signature(&self, node: &tree_sitter::Node, source: &str) -> String {
-        let start = node.start_byte();
-        let text = source
-            .get(start..node.end_byte().min(source.len()))
-            .unwrap_or("…");
-        let line = text.split('\n').next().unwrap_or("").trim();
-        if line.is_empty() {
-            "…".to_string()
-        } else {
-            line.to_string()
-        }
-    }
-
     fn has_doc_comment(&self, _node: &tree_sitter::Node) -> bool {
         true
     }

crates/ctx-symbol/src/lang/csharp.rs

@@ -62,19 +62,6 @@ impl Language for CSharpLang {
             .map(|s| s.trim().to_string())
     }
 
-    fn signature(&self, node: &tree_sitter::Node, source: &str) -> String {
-        let start = node.start_byte();
-        let text = source
-            .get(start..node.end_byte().min(source.len()))
-            .unwrap_or("…");
-        let line = text.split('\n').next().unwrap_or("").trim();
-        if line.is_empty() {
-            "…".to_string()
-        } else {
-            line.to_string()
-        }
-    }
-
     fn has_doc_comment(&self, _node: &tree_sitter::Node) -> bool {
         true
     }

crates/ctx-symbol/src/lang/go.rs

@@ -43,19 +43,6 @@ impl Language for GoLang {
             .map(|s| s.trim().to_string())
     }
 
-    fn signature(&self, node: &tree_sitter::Node, source: &str) -> String {
-        let start = node.start_byte();
-        let text = source
-            .get(start..node.end_byte().min(source.len()))
-            .unwrap_or("…");
-        let line = text.split('\n').next().unwrap_or("").trim();
-        if line.is_empty() {
-            "…".to_string()
-        } else {
-            line.to_string()
-        }
-    }
-
     fn has_doc_comment(&self, _node: &tree_sitter::Node) -> bool {
         true
     }

crates/ctx-symbol/src/lang/html.rs

@@ -64,18 +64,4 @@ impl Language for HtmlLang {
         }
         None
     }
-
-    fn signature(&self, node: &tree_sitter::Node, source: &str) -> String {
-        // `<tag id="value">` — the opening line only.
-        let start = node.start_byte();
-        let text = source
-            .get(start..node.end_byte().min(source.len()))
-            .unwrap_or("…");
-        let line = text.split('\n').next().unwrap_or("").trim();
-        if line.is_empty() {
-            "…".to_string()
-        } else {
-            line.to_string()
-        }
-    }
 }

crates/ctx-symbol/src/lang/java.rs

@@ -52,19 +52,6 @@ impl Language for JavaLang {
             .map(|s| s.trim().to_string())
     }
 
-    fn signature(&self, node: &tree_sitter::Node, source: &str) -> String {
-        let start = node.start_byte();
-        let text = source
-            .get(start..node.end_byte().min(source.len()))
-            .unwrap_or("…");
-        let line = text.split('\n').next().unwrap_or("").trim();
-        if line.is_empty() {
-            "…".to_string()
-        } else {
-            line.to_string()
-        }
-    }
-
     fn has_doc_comment(&self, _node: &tree_sitter::Node) -> bool {
         true
     }

crates/ctx-symbol/src/lang/javascript.rs

@@ -1,5 +1,6 @@
 //! JavaScript language backend.
 
+use crate::lang::util::string_value;
 use crate::language::Language;
 use crate::symbol::SymbolKind;
 use std::path::Path;
@@ -50,19 +51,6 @@ impl Language for JavaScriptLang {
             .map(|s| s.trim().to_string())
     }
 
-    fn signature(&self, node: &tree_sitter::Node, source: &str) -> String {
-        let start = node.start_byte();
-        let text = source
-            .get(start..node.end_byte().min(source.len()))
-            .unwrap_or("…");
-        let line = text.split('\n').next().unwrap_or("").trim();
-        if line.is_empty() {
-            "…".to_string()
-        } else {
-            line.to_string()
-        }
-    }
-
     fn has_doc_comment(&self, _node: &tree_sitter::Node) -> bool {
         true
     }
@@ -106,15 +94,3 @@ impl Language for JavaScriptLang {
         .unwrap_or_default()
     }
 }
-
-/// Text of a string literal node without its quotes.
-fn string_value(node: tree_sitter::Node, source: &str) -> Option<String> {
-    let text = node.utf8_text(source.as_bytes()).ok()?.trim();
-    let unquoted = text.strip_prefix(['\'', '"'])?;
-    Some(
-        unquoted
-            .strip_suffix(['\'', '"'])
-            .unwrap_or(unquoted)
-            .to_string(),
-    )
-}

crates/ctx-symbol/src/lang/lua.rs

@@ -56,19 +56,6 @@ impl Language for LuaLang {
             .map(|s| s.trim().to_string())
     }
 
-    fn signature(&self, node: &tree_sitter::Node, source: &str) -> String {
-        let start = node.start_byte();
-        let text = source
-            .get(start..node.end_byte().min(source.len()))
-            .unwrap_or("…");
-        let line = text.split('\n').next().unwrap_or("").trim();
-        if line.is_empty() {
-            "…".to_string()
-        } else {
-            line.to_string()
-        }
-    }
-
     fn has_doc_comment(&self, _node: &tree_sitter::Node) -> bool {
         true
     }
@@ -111,12 +98,5 @@ fn string_value(node: tree_sitter::Node, source: &str) -> Option<String> {
     {
         return Some(text.trim().to_string());
     }
-    let text = node.utf8_text(source.as_bytes()).ok()?.trim();
-    let unquoted = text.strip_prefix(['\'', '"'])?;
-    Some(
-        unquoted
-            .strip_suffix(['\'', '"'])
-            .unwrap_or(unquoted)
-            .to_string(),
-    )
+    crate::lang::util::string_value(node, source)
 }

crates/ctx-symbol/src/lang/markdown.rs

@@ -48,19 +48,6 @@ impl Language for MarkdownLang {
         Some(cleaned.to_string())
     }
 
-    /// The full heading line as written (`## Sub heading`).
-    fn signature(&self, node: &tree_sitter::Node, source: &str) -> String {
-        let text = source
-            .get(node.start_byte()..node.end_byte().min(source.len()))
-            .unwrap_or("…");
-        let line = text.split('\n').next().unwrap_or("").trim();
-        if line.is_empty() {
-            "…".to_string()
-        } else {
-            line.to_string()
-        }
-    }
-
     /// Extend the heading's range to its enclosing `section`, i.e. through
     /// the whole chapter including nested subsections.
     fn definition_byte_range(&self, node: &tree_sitter::Node) -> std::ops::Range<usize> {

crates/ctx-symbol/src/lang/mod.rs

@@ -15,3 +15,4 @@ pub mod python;
 pub mod ruby;
 pub mod rust;
 pub mod typescript;
+pub(crate) mod util;

crates/ctx-symbol/src/lang/python.rs

@@ -48,19 +48,6 @@ impl Language for PythonLang {
             .map(|s| s.trim().to_string())
     }
 
-    fn signature(&self, node: &tree_sitter::Node, source: &str) -> String {
-        let start = node.start_byte();
-        let text = source
-            .get(start..node.end_byte().min(source.len()))
-            .unwrap_or("…");
-        let line = text.split('\n').next().unwrap_or("").trim();
-        if line.is_empty() {
-            "…".to_string()
-        } else {
-            line.to_string()
-        }
-    }
-
     fn has_doc_comment(&self, _node: &tree_sitter::Node) -> bool {
         true
     }

crates/ctx-symbol/src/lang/ruby.rs

@@ -1,5 +1,6 @@
 //! Ruby language backend.
 
+use crate::lang::util::string_value;
 use crate::language::Language;
 use crate::symbol::SymbolKind;
 use std::path::Path;
@@ -40,19 +41,6 @@ impl Language for RubyLang {
             .map(|s| s.trim().to_string())
     }
 
-    fn signature(&self, node: &tree_sitter::Node, source: &str) -> String {
-        let start = node.start_byte();
-        let text = source
-            .get(start..node.end_byte().min(source.len()))
-            .unwrap_or("…");
-        let line = text.split('\n').next().unwrap_or("").trim();
-        if line.is_empty() {
-            "…".to_string()
-        } else {
-            line.to_string()
-        }
-    }
-
     fn has_doc_comment(&self, _node: &tree_sitter::Node) -> bool {
         true
     }
@@ -111,15 +99,3 @@ impl Language for RubyLang {
         .unwrap_or_default()
     }
 }
-
-/// Text of a string literal node without its quotes.
-fn string_value(node: tree_sitter::Node, source: &str) -> Option<String> {
-    let text = node.utf8_text(source.as_bytes()).ok()?.trim();
-    let unquoted = text.strip_prefix(['\'', '"'])?;
-    Some(
-        unquoted
-            .strip_suffix(['\'', '"'])
-            .unwrap_or(unquoted)
-            .to_string(),
-    )
-}

crates/ctx-symbol/src/lang/rust.rs

@@ -47,19 +47,6 @@ impl Language for RustLang {
             .map(|s| s.trim().to_string())
     }
 
-    fn signature(&self, node: &tree_sitter::Node, source: &str) -> String {
-        let start = node.start_byte();
-        let text = source
-            .get(start..node.end_byte().min(source.len()))
-            .unwrap_or("…");
-        let line = text.split('\n').next().unwrap_or("").trim();
-        if line.is_empty() {
-            "…".to_string()
-        } else {
-            line.to_string()
-        }
-    }
-
     fn has_doc_comment(&self, _node: &tree_sitter::Node) -> bool {
         true
     }

crates/ctx-symbol/src/lang/typescript.rs

@@ -1,5 +1,6 @@
 //! TypeScript / JavaScript language backend.
 
+use crate::lang::util::string_value;
 use crate::language::Language;
 use crate::symbol::SymbolKind;
 use std::path::Path;
@@ -65,19 +66,6 @@ impl Language for TypeScriptLang {
             .map(|s| s.trim().to_string())
     }
 
-    fn signature(&self, node: &tree_sitter::Node, source: &str) -> String {
-        let start = node.start_byte();
-        let text = source
-            .get(start..node.end_byte().min(source.len()))
-            .unwrap_or("…");
-        let line = text.split('\n').next().unwrap_or("").trim();
-        if line.is_empty() {
-            "…".to_string()
-        } else {
-            line.to_string()
-        }
-    }
-
     fn has_doc_comment(&self, _node: &tree_sitter::Node) -> bool {
         true
     }
@@ -134,15 +122,3 @@ impl Language for TypeScriptLang {
         vec![target]
     }
 }
-
-/// Text of a string literal node without its quotes.
-fn string_value(node: tree_sitter::Node, source: &str) -> Option<String> {
-    let text = node.utf8_text(source.as_bytes()).ok()?.trim();
-    let unquoted = text.strip_prefix(['\'', '"'])?;
-    Some(
-        unquoted
-            .strip_suffix(['\'', '"'])
-            .unwrap_or(unquoted)
-            .to_string(),
-    )
-}

crates/ctx-symbol/src/lang/util.rs

@@ -0,0 +1,13 @@
+//! Helpers shared by language backends.
+
+/// Text of a string literal node without its quotes.
+pub(crate) fn string_value(node: tree_sitter::Node, source: &str) -> Option<String> {
+    let text = node.utf8_text(source.as_bytes()).ok()?.trim();
+    let unquoted = text.strip_prefix(['\'', '"'])?;
+    Some(
+        unquoted
+            .strip_suffix(['\'', '"'])
+            .unwrap_or(unquoted)
+            .to_string(),
+    )
+}