Adding more styling options for users

.gitignore

@@ -1,2 +1,3 @@
 /target
-Cargo.lock
+Cargo.lock
+.idea

src/draw.rs

@@ -53,6 +53,30 @@ impl Characters {
         }
     }
 
+    pub fn unicode_straight() -> Self {
+        Self {
+            hbar: '─',
+            vbar: '│',
+            xbar: '┼',
+            vbar_break: '┆',
+            vbar_gap: '┆',
+            uarrow: '▲',
+            rarrow: '▶',
+            ltop: '┌',
+            mtop: '┬',
+            rtop: '┐',
+            lbot: '└',
+            mbot: '┴',
+            rbot: '┘',
+            lbox: '[',
+            rbox: ']',
+            lcross: '├',
+            rcross: '┤',
+            underbar: '┬',
+            underline: '─',
+        }
+    }
+
     pub fn ascii() -> Self {
         Self {
             hbar: '-',

src/lib.rs

@@ -354,6 +354,8 @@ pub enum LabelAttach {
 pub enum CharSet {
     /// Unicode characters (an attempt is made to use only commonly-supported characters).
     Unicode,
+    /// Unicode characters for box drawing, using straight lines instead of curved ones.
+    UnicodeStraight,
     /// ASCII-only characters.
     Ascii,
 }

src/write.rs

@@ -149,6 +149,7 @@ impl<S: Span> Report<'_, S> {
     ) -> io::Result<()> {
         let draw = match self.config.char_set {
             CharSet::Unicode => draw::Characters::unicode(),
+            CharSet::UnicodeStraight => draw::Characters::unicode_straight(),
             CharSet::Ascii => draw::Characters::ascii(),
         };
 
@@ -1184,4 +1185,51 @@ mod tests {
         ---'
         "###)
     }
+
+    #[test]
+    fn unicode_style() {
+        let source = "apple == orange;";
+        let msg = Report::<Range<usize>>::build(ReportKind::Error, (), 0)
+            .with_config(Config::default().with_char_set(CharSet::Unicode).with_color(false))
+            .with_message("can't compare apples with oranges")
+            .with_label(Label::new(0..5).with_message("This is an apple"))
+            .with_label(Label::new(9..15).with_message("This is an orange"))
+            .finish()
+            .write_to_string(Source::from(source));
+        assert_snapshot!(msg, @r###"
+        Error: can't compare apples with oranges
+           ╭─[<unknown>:1:1]
+           │
+         1 │ apple == orange;
+           │ ──┬──    ───┬──  
+           │   ╰────────────── This is an apple
+           │             │    
+           │             ╰──── This is an orange
+        ───╯
+        "###)
+    }
+
+        #[test]
+    fn unicode_stright_style() {
+        let source = "apple == orange;";
+        let msg = Report::<Range<usize>>::build(ReportKind::Error, (), 0)
+            .with_config(Config::default().with_char_set(CharSet::UnicodeStraight).with_color(false))
+            .with_message("can't compare apples with oranges")
+            .with_label(Label::new(0..5).with_message("This is an apple"))
+            .with_label(Label::new(9..15).with_message("This is an orange"))
+            .finish()
+            .write_to_string(Source::from(source));
+        assert_snapshot!(msg, @r###"
+        Error: can't compare apples with oranges
+           ┌─[<unknown>:1:1]
+           │
+         1 │ apple == orange;
+           │ ──┬──    ───┬──  
+           │   └────────────── This is an apple
+           │             │    
+           │             └──── This is an orange
+        ───┘
+        "###)
+    }
 }
+