Add carrots to snippet printing in case colors aren't used, also use column information. Resolves #273.

Author: jeremy-rifkin

README.md

@@ -342,6 +342,14 @@ namespace cpptrace {
         bool color = false
     );
 
+    std::string get_snippet(
+        const std::string& path,
+        std::size_t line,
+        nullable<std::uint32_t> column,
+        std::size_t context_size,
+        bool color = false
+    );
+
     bool isatty(int fd);
 
     extern const int stdin_fileno;

include/cpptrace/utils.hpp

@@ -27,6 +27,14 @@ CPPTRACE_BEGIN_NAMESPACE
         bool color = false
     );
 
+    CPPTRACE_EXPORT std::string get_snippet(
+        const std::string& path,
+        std::size_t line,
+        nullable<std::uint32_t> column,
+        std::size_t context_size,
+        bool color = false
+    );
+
     CPPTRACE_EXPORT bool isatty(int fd);
 
     CPPTRACE_EXPORT extern const int stdin_fileno;

src/formatting.cpp

@@ -263,6 +263,7 @@ CPPTRACE_BEGIN_NAMESPACE
                         auto snippet = detail::get_snippet(
                             frame.filename,
                             frame.line.value(),
+                            frame.column,
                             options.context_lines,
                             color
                         );

src/snippets/snippet.cpp

@@ -104,7 +104,13 @@ namespace detail {
     constexpr std::size_t margin_width = 8;
 
     // 1-indexed line
-    std::string get_snippet(const std::string& path, std::size_t target_line, std::size_t context_size, bool color) {
+    std::string get_snippet(
+        const std::string& path,
+        std::size_t target_line,
+        nullable<std::uint32_t> column,
+        std::size_t context_size,
+        bool color
+    ) {
         const auto& manager = get_manager(path);
         if(!manager.ok()) {
             return "";
@@ -126,15 +132,35 @@ namespace detail {
         // make the snippet
         std::string snippet;
         for(auto line = begin; line <= end; line++) {
-            if(color && line == target_line) {
-                snippet += YELLOW;
-            }
             auto line_str = std::to_string(line);
-            snippet += microfmt::format("{>{}}: ", margin_width, line_str);
-            if(color && line == target_line) {
-                snippet += RESET;
+            if(line == target_line) {
+                if(color) {
+                    snippet += YELLOW;
+                }
+                auto line_width = line_str.size() + 3;
+                snippet += microfmt::format(
+                    "{>{}} > {}: ",
+                    line_width > margin_width ? 0 : margin_width - line_width,
+                    "",
+                    line_str
+                );
+                if(color) {
+                    snippet += RESET;
+                }
+            } else {
+                snippet += microfmt::format("{>{}}: ", margin_width, line_str);
             }
             snippet += lines[line - original_begin];
+            if(line == target_line && column.has_value()) {
+                snippet += microfmt::format("\n{>{}}", margin_width + 2 + column.value() - 1, "");
+                if(color) {
+                    snippet += YELLOW;
+                }
+                snippet += "^";
+                if(color) {
+                    snippet += RESET;
+                }
+            }
             if(line != end) {
                 snippet += '\n';
             }

src/snippets/snippet.hpp

@@ -4,12 +4,18 @@
 #include <cstddef>
 #include <string>
 
-#include <cpptrace/forward.hpp>
+#include <cpptrace/basic.hpp>
 
 CPPTRACE_BEGIN_NAMESPACE
 namespace detail {
     // 1-indexed line
-    std::string get_snippet(const std::string& path, std::size_t line, std::size_t context_size, bool color);
+    std::string get_snippet(
+        const std::string& path,
+        std::size_t line,
+        nullable<std::uint32_t> column,
+        std::size_t context_size,
+        bool color
+    );
 }
 CPPTRACE_END_NAMESPACE
 

src/utils.cpp

@@ -20,7 +20,17 @@ CPPTRACE_BEGIN_NAMESPACE
     }
 
     std::string get_snippet(const std::string& path, std::size_t line, std::size_t context_size, bool color) {
-        return detail::get_snippet(path, line, context_size, color);
+        return detail::get_snippet(path, line, nullable<std::uint32_t>::null(), context_size, color);
+    }
+
+    std::string get_snippet(
+        const std::string& path,
+        std::size_t line,
+        nullable<std::uint32_t> column,
+        std::size_t context_size,
+        bool color
+    ) {
+        return detail::get_snippet(path, line, column, context_size, color);
     }
 
     bool isatty(int fd) {

test/link_test.cpp

@@ -68,6 +68,9 @@ int main() {
 
     cpptrace::demangle("test");
     cpptrace::get_snippet(__FILE__, 1, 1);
+    cpptrace::get_snippet(__FILE__, 1, 1, false);
+    cpptrace::get_snippet(__FILE__, 1, 1, 1);
+    cpptrace::get_snippet(__FILE__, 1, 1, 1, false);
     cpptrace::isatty(cpptrace::stderr_fileno);
 
     cpptrace::register_terminate_handler();