start doing error reporting

Cargo.toml

@@ -38,6 +38,7 @@ rayon = "1.5.3"
 nalgebra = "0.31.1"
 approx = "0.5.1"
 unicode-normalization = "0.1.21"
+thiserror = "1.0.34"
 cozorocks = { path = "cozorocks" }
 
 #[target.'cfg(not(target_env = "msvc"))'.dependencies]

cozorocks/src/bridge/mod.rs

@@ -257,7 +257,7 @@ impl Diagnostic for ffi::RocksDbStatus {
             None
         } else {
             Some(Box::new(format!(
-                "cozorocks::{:?}::{:?}",
+                "rocksdb::{:?}::{:?}",
                 self.code, self.subcode
             )))
         }
@@ -268,6 +268,9 @@ impl Diagnostic for ffi::RocksDbStatus {
             _ => Some(Severity::Error),
         }
     }
+    fn help<'a>(&'a self) -> Option<Box<dyn Display + 'a>> {
+        Some(Box::new("This error is usually outside Cozo's control"))
+    }
 }
 
 impl ffi::RocksDbStatus {

src/parse/mod.rs

@@ -1,21 +1,22 @@
 use std::collections::BTreeMap;
 
-use miette::{IntoDiagnostic, Result};
+use miette::{Diagnostic, Result};
+use pest::error::InputLocation;
 use pest::Parser;
 
 use crate::data::program::InputProgram;
 use crate::data::value::DataValue;
 use crate::parse::query::parse_query;
-use crate::parse::schema::{AttrTxItem, parse_schema};
+use crate::parse::schema::{parse_schema, AttrTxItem};
 use crate::parse::sys::{parse_sys, SysOp};
 use crate::parse::tx::{parse_tx, Quintuple};
 
 pub(crate) mod expr;
 pub(crate) mod pull;
 pub(crate) mod query;
-pub(crate) mod tx;
 pub(crate) mod schema;
 pub(crate) mod sys;
+pub(crate) mod tx;
 
 #[derive(pest_derive::Parser)]
 #[grammar = "cozoscript.pest"]
@@ -28,7 +29,26 @@ pub(crate) enum CozoScript {
     Query(InputProgram),
     Tx(Vec<Quintuple>),
     Schema(Vec<AttrTxItem>),
-    Sys(SysOp)
+    Sys(SysOp),
+}
+
+#[derive(thiserror::Error, Diagnostic, Debug)]
+#[error("The query parser has encountered unexpected input / end of input")]
+#[diagnostic(code(parse::pest))]
+pub struct ParseError {
+    #[label("here")]
+    span: (usize, usize),
+}
+
+impl From<pest::error::Error<Rule>> for ParseError {
+    fn from(err: pest::error::Error<Rule>) -> Self {
+        match err.location {
+            InputLocation::Pos(p) => Self { span: (p, 0) },
+            InputLocation::Span((start, end)) => Self {
+                span: (start, end - start),
+            },
+        }
+    }
 }
 
 pub(crate) fn parse_script(
@@ -36,7 +56,7 @@ pub(crate) fn parse_script(
     param_pool: &BTreeMap<String, DataValue>,
 ) -> Result<CozoScript> {
     let parsed = CozoScriptParser::parse(Rule::script, src)
-        .into_diagnostic()?
+        .map_err(|e| ParseError::from(e))?
         .next()
         .unwrap();
     Ok(match parsed.as_rule() {

src/runtime/db.rs

@@ -280,7 +280,9 @@ impl Db {
             .iter()
             .map(|(k, v)| (k.clone(), DataValue::from(v)))
             .collect();
-        match parse_script(payload, &param_pool)? {
+        match parse_script(payload, &param_pool)
+            .map_err(|e| e.with_source_code(payload.to_string()))?
+        {
             CozoScript::Query(p) => self.run_query(p),
             CozoScript::Tx(tx) => self.transact_triples(tx),
             CozoScript::Schema(schema) => self.transact_attributes(schema),