WIP drawing diagnostics

wright/src/reporting.rs

@@ -5,6 +5,7 @@
 //! [codespan-reporting]: https://crates.io/crates/codespan-reporting
 //! [ariadne]: https://crates.io/crates/ariadne
 
+use crate::source_tracking::fragment::Fragment;
 use self::{owned_string::OwnedString, severity::Severity};
 use std::io;
 use termcolor::{ColorChoice, StandardStream, StandardStreamLock, WriteColor};
@@ -25,6 +26,28 @@ pub struct Diagnostic {
 
     /// The main message of the diagnostic. This should be short enough to display on one terminal line in most cases.
     pub message: OwnedString,
+
+    /// The primary [Highlight] of this diagnostic, which contains the section of source code where the
+    /// error/warning lies.
+    pub primary_highlight: Option<Highlight>,
+
+    /// Any secondary [Highlight]s that help the reader understand this diagnostic. 
+    pub secondary_highlights: Vec<Highlight>,
+
+    /// Optionally a note giving extra context or re-stating this diagnostic. 
+    pub note: Option<OwnedString>,
+}
+
+/// Some highlighted source code that can be printed with a [Diagnostic], usually with its own message(s).
+#[derive(Debug)] 
+pub struct Highlight {
+    /// A valid [Fragment] representing the source where the error occurred.
+    /// The surrounding source will be printed to the best of the ability of this
+    /// implementation, which may be modified or updated to better draw [Diagnostic]s.
+    pub fragment: Fragment,
+
+    /// Optionally a message to display with the highlighted region. 
+    pub message: Option<OwnedString>,
 }
 
 impl Diagnostic {
@@ -37,6 +60,9 @@ impl Diagnostic {
             severity,
             code: None,
             message: message.into(),
+            primary_highlight: None,
+            secondary_highlights: Vec::new(),
+            note: None
         }
     }
 
@@ -70,6 +96,24 @@ impl Diagnostic {
         self
     }
 
+    /// Add a [Diagnostic::note] to this [Diagnostic].
+    pub fn with_note(mut self, n: impl Into<OwnedString>) -> Self {
+        self.note = Some(n.into());
+        self
+    }
+
+    /// Add a [Diagnostic::primary_highlight] to this [Diagnostic].
+    pub fn with_primary_highlight(mut self, h: Highlight) -> Self {
+        self.primary_highlight = Some(h);
+        self
+    }
+
+    /// Add a secondary [Highlight] to this [Diagnostic]'s list of [Diagnostic::secondary_highlights].
+    pub fn add_secondary_highlight(mut self, h: Highlight) -> Self {
+        self.secondary_highlights.push(h);
+        self
+    }
+
     /// Print this diagnostic to the standard output.
     ///
     /// Uses [supports_unicode] to determine whether to print unicode characters.

wright/src/reporting/draw.rs

@@ -4,7 +4,30 @@
 
 use std::io;
 use termcolor::{ColorSpec, WriteColor};
-use super::Diagnostic;
+use super::{Diagnostic, Highlight};
+
+/// Prefix added to the beginning of every line in a section (such as a [Highlight] or [Diagnostic::note])
+/// when unicode is not available. 
+const ASCII_SECTION_PREFIX: char = '|';
+
+/// Prefix added to the beginning of every line in a section (such as a [Highlight] or [Diagnostic::note])
+/// when unicode is available.
+const UNICODE_SECTION_PREFIX: char = '\u{2503}';
+
+/// Character to print on the first/header line of a section that connects to the prefix characters on following lines. 
+const UNICODE_SECTION_OPENER: char = '\u{250F}';
+
+/// Character to print on the first/header line of a section that connects to the prefix characters on following lines. 
+const ASCII_SECTION_OPENER: char = '=';
+
+/// Character to print after the last line of a section that connects to the prefix characters on previous lines. 
+const UNICODE_SECTION_CLOSER: char = '\u{2579}';
+
+/// Character to print after the last line of a section that connects to the prefix characters on previous lines. 
+/// 
+/// This is just a space for ASCII as there is not a great way to close sections otherwise. 
+const ASCII_SECTION_CLOSER: char = ' ';
+
 
 /// Draw a [Diagnostic] to a [WriteColor] reciever, optionally using unicode. 
 pub fn draw<W: WriteColor>(diagnostic: &Diagnostic, w: &mut W, write_unicode: bool) -> io::Result<()> {
@@ -78,5 +101,20 @@ mod tests {
         assert_eq!(without_unicode, "error [TEST_001]: test error\n");
         assert_eq!(without_unicode, with_unicode);
     }
+
+    // Run this with `cargo test test_unicode_vs_ascii -- --include-ignored --nocapture` to print the constants \
+    // used in this module.
+    #[test]
+    #[ignore = "print-debugging tests ignored by default"]
+    fn test_unicode_vs_ascii() {
+        use super::{UNICODE_SECTION_CLOSER, UNICODE_SECTION_OPENER, UNICODE_SECTION_PREFIX};
+
+        // Print unicode section: 
+        println!("{UNICODE_SECTION_OPENER} Note: \
+                \n{UNICODE_SECTION_PREFIX} Test note \
+                \n{UNICODE_SECTION_PREFIX} \
+                \n{UNICODE_SECTION_CLOSER}");
+
+    }
 }