stuff

src/v1/parser/error.rs

@@ -0,0 +1,50 @@
+use super::{token::{FileRegion, TokenInstance}, FilePos};
+
+#[derive(Debug)]
+pub struct ParserError {
+    pub msg: String,
+    pub regions: Vec<FileRegion>,
+}
+
+impl ParserError {
+    pub fn from_instances(instances: &[&TokenInstance], msg: String) -> Self {
+        ParserError {
+            msg,
+            regions: instances.iter().map(|i| i.region).collect(),
+        }
+    }
+    pub fn from_msg(msg: String) -> Self {
+        Self {
+            msg,
+            regions: Vec::new(),
+        }
+    }
+    pub fn at(pos: FilePos, msg: String) -> Self {
+        Self {
+            msg,
+            regions: vec![FileRegion {
+                start: pos,
+                end: pos,
+            }],
+        }
+    }
+    pub fn unexpected_end() -> Self {
+        Self::from_msg("unexpected end of input".to_string())
+    }
+    pub fn unexpected_token(inst: &TokenInstance, expected: &str) -> Self {
+        let t = &inst.token;
+        ParserError::from_instances(
+            &[inst],
+            format!("Unexpected token {t:?}; expected {expected}"),
+        )
+    }
+    pub fn write_for(&self, writer: &mut impl std::io::Write, file: &str) -> std::io::Result<()> {
+        let after = if self.regions.is_empty() { "" } else { ":" };
+        writeln!(writer, "error: {}{}", self.msg, after)?;
+        for reg in &self.regions {
+            reg.write_for(writer, file)?;
+        }
+        Ok(())
+    }
+}
+