Introduce SyntaxErrorKind and TextRange in SyntaxError

crates/ra_syntax/src/yellow/syntax_error.rs

@@ -0,0 +1,42 @@
+use std::fmt;
+
+use crate::TextRange;
+
+#[derive(Debug, Clone, PartialEq, Eq, Hash)]
+pub struct SyntaxError {
+    pub kind: SyntaxErrorKind,
+    pub range: TextRange,
+}
+
+impl SyntaxError {
+    pub fn new(kind: SyntaxErrorKind, range: TextRange) -> SyntaxError {
+        SyntaxError { kind, range }
+    }
+}
+
+#[derive(Debug, Clone, PartialEq, Eq, Hash)]
+pub enum SyntaxErrorKind {
+    ParseError(ParseError),
+    EmptyChar,
+    UnclosedChar,
+    LongChar,
+    EmptyAsciiEscape,
+    InvalidAsciiEscape,
+}
+
+#[derive(Debug, Clone, PartialEq, Eq, Hash)]
+pub struct ParseError(pub String);
+
+impl fmt::Display for SyntaxErrorKind {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        use self::SyntaxErrorKind::*;
+        match self {
+            EmptyAsciiEscape => write!(f, "Empty escape sequence"),
+            InvalidAsciiEscape => write!(f, "Invalid escape sequence"),
+            EmptyChar => write!(f, "Empty char literal"),
+            UnclosedChar => write!(f, "Unclosed char literal"),
+            LongChar => write!(f, "Char literal should be one character long"),
+            ParseError(msg) => write!(f, "{}", msg.0),
+        }
+    }
+}