Fix SQL/frontend naming mismatches and multiline scripts

ROADMAP.md

@@ -28,7 +28,7 @@ This document tracks the current state and next steps for the repository.
 - [x] Minimal SQL AST and parser
 - [x] Logical plan scaffolding
 - [x] Logical-plan execution for the first SQL slice
-- [x] `SELECT-FROM-WHERE` support with positional or named columns
+- [x] `SELECT-FROM-WHERE-ORDER BY` support with positional or named columns
 - [x] Basic multi-table SQL joins via qualified-column filtering
 - [x] Table aliases for self-joins and qualified references
 - [x] Basic `ORDER BY` support over output columns

src/frontend/language.rs

@@ -22,6 +22,8 @@ pub enum Command {
 
 pub fn parse_script(input: &str) -> Result<Vec<Command>, String> {
     let mut commands = Vec::new();
+    let mut pending = String::new();
+    let mut start_line = 0usize;
 
     for (index, raw_line) in input.lines().enumerate() {
         let line = raw_line.trim();
@@ -29,7 +31,26 @@ pub fn parse_script(input: &str) -> Result<Vec<Command>, String> {
             continue;
         }
 
-        let command = parse_command(line).map_err(|err| format!("line {}: {}", index + 1, err))?;
+        if pending.is_empty() {
+            start_line = index + 1;
+        } else {
+            pending.push(' ');
+        }
+        pending.push_str(line);
+
+        if !command_is_complete(&pending) {
+            continue;
+        }
+
+        let command =
+            parse_command(&pending).map_err(|err| format!("line {}: {}", start_line, err))?;
+        commands.push(command);
+        pending.clear();
+    }
+
+    if !pending.is_empty() {
+        let command =
+            parse_command(&pending).map_err(|err| format!("line {}: {}", start_line, err))?;
         commands.push(command);
     }
 
@@ -62,11 +83,15 @@ pub fn parse_command(input: &str) -> Result<Command, String> {
 
     if let Some(rest) = strip_keyword(trimmed, "schema") {
         let atom = parse_atom(trim_suffix(rest, '.')?)?;
+        validate_identifier(&atom.predicate, "schema table")?;
         let columns = atom
             .terms
             .into_iter()
             .map(|term| match term {
-                Term::Constant(name) => Ok(name),
+                Term::Constant(name) => {
+                    validate_identifier(&name, "schema column")?;
+                    Ok(name)
+                }
                 Term::Null(_) | Term::Variable(_) => {
                     Err("schema columns must be constant identifiers".to_string())
                 }
@@ -121,6 +146,18 @@ pub fn parse_command(input: &str) -> Result<Command, String> {
     Err("unknown command; try `help`".to_string())
 }
 
+fn command_is_complete(input: &str) -> bool {
+    let trimmed = input.trim();
+    trimmed.ends_with('.')
+        || trimmed.ends_with(';')
+        || trimmed.ends_with('?')
+        || trimmed.eq_ignore_ascii_case("run")
+        || trimmed.eq_ignore_ascii_case("show facts")
+        || trimmed.eq_ignore_ascii_case("show rules")
+        || trimmed.eq_ignore_ascii_case("reset")
+        || trimmed.eq_ignore_ascii_case("help")
+}
+
 fn strip_keyword<'a>(input: &'a str, keyword: &str) -> Option<&'a str> {
     let prefix = input.get(..keyword.len())?;
     if !prefix.eq_ignore_ascii_case(keyword) {
@@ -258,11 +295,20 @@ fn validate_identifier(value: &str, label: &str) -> Result<(), String> {
         return Err(format!("{} cannot be empty", label));
     }
 
-    if value.chars().all(is_identifier_char) {
-        Ok(())
-    } else {
-        Err(format!("invalid {} `{}`", label, value))
+    let mut chars = value.chars();
+    let Some(first) = chars.next() else {
+        return Err(format!("{} cannot be empty", label));
+    };
+
+    if !is_identifier_start_char(first) || !chars.all(is_identifier_char) {
+        return Err(format!("invalid {} `{}`", label, value));
     }
+
+    Ok(())
+}
+
+fn is_identifier_start_char(ch: char) -> bool {
+    ch.is_ascii_alphanumeric() || ch == '_'
 }
 
 fn is_identifier_char(ch: char) -> bool {
@@ -475,6 +521,32 @@ mod tests {
         }
     }
 
+    #[test]
+    fn parse_schema_command_rejects_non_identifier_columns() {
+        let error = parse_command(r#"schema Parent("given name", child)."#).unwrap_err();
+        assert_eq!(error, "invalid schema column `given name`");
+    }
+
+    #[test]
+    fn parse_script_supports_multiline_sql() {
+        let script = "fact Parent(alice, bob).\n\
+                      fact Parent(bob, carol).\n\
+                      schema Parent(parent, child).\n\
+                      sql SELECT parent\n\
+                      FROM Parent\n\
+                      WHERE child = 'bob';";
+
+        let commands = parse_script(script).unwrap();
+        assert_eq!(commands.len(), 4);
+        match &commands[3] {
+            Command::Sql(select) => {
+                assert_eq!(select.from.len(), 1);
+                assert_eq!(select.from[0].name, "Parent");
+            }
+            other => panic!("unexpected command: {:?}", other),
+        }
+    }
+
     #[test]
     fn parse_query_command() {
         let command = parse_command("query Ancestor(?X, ?Y), Parent(?Y, ?Z)?").unwrap();

src/lib.rs

@@ -3,7 +3,8 @@
 //! The current codebase primarily contains a chase-based reasoning core plus
 //! lightweight frontends for experimenting with rule-driven query answering.
 //! It also contains an early relational and SQL scaffold for a narrow
-//! single-table `SELECT-FROM-WHERE` slice. It is not yet a full SQL engine.
+//! `SELECT-FROM-WHERE-ORDER BY` slice with basic joins, aliases, and
+//! conjunctions. It is not yet a full SQL engine.
 
 pub mod catalog;
 pub mod chase;

src/planner/mod.rs

@@ -5,8 +5,9 @@
 //! - [`logical`]: plan and expression data structures
 //! - [`sql`]: translation from SQL AST into the current logical-plan subset
 //!
-//! At the moment this is intentionally small and only covers the first
-//! single-table SQL slice.
+//! At the moment this is intentionally small and covers the current SQL slice:
+//! filtering, ordering, projection, and basic joins over predicate-backed
+//! tables.
 
 pub mod logical;
 pub mod sql;

src/sql/ast.rs

@@ -1,4 +1,4 @@
-/// A parsed `SELECT-FROM-WHERE` statement in the current SQL subset.
+/// A parsed `SELECT-FROM-WHERE-ORDER BY` statement in the current SQL subset.
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub struct Select {
     /// Output expressions requested by the query.

src/sql/mod.rs

@@ -1,7 +1,8 @@
 //! Minimal SQL front-end scaffolding.
 //!
-//! The current SQL layer supports a narrow `SELECT-FROM-WHERE` subset over one
-//! predicate-backed table. It provides:
+//! The current SQL layer supports a narrow `SELECT-FROM-WHERE-ORDER BY` subset
+//! over predicate-backed tables, including comma-join style multi-table
+//! queries, table aliases, and `AND` in filter predicates. It provides:
 //!
 //! - a small AST in [`ast`]
 //! - a parser in [`parser`]

src/sql/parser.rs

@@ -48,7 +48,7 @@ enum Token {
     Eq,
 }
 
-/// Parse a `SELECT-FROM-WHERE` query in the current SQL subset.
+/// Parse a `SELECT-FROM-WHERE-ORDER BY` query in the current SQL subset.
 pub fn parse_select(input: &str) -> Result<Select, ParseError> {
     let tokens = tokenize(input)?;
     let mut parser = Parser::new(tokens);
@@ -337,11 +337,11 @@ where
 }
 
 fn is_identifier_start(ch: char) -> bool {
-    ch.is_ascii_alphabetic() || ch == '_'
+    ch.is_ascii_alphanumeric() || ch == '_'
 }
 
 fn is_identifier_part(ch: char) -> bool {
-    ch.is_ascii_alphanumeric() || matches!(ch, '_' | '.')
+    ch.is_ascii_alphanumeric() || matches!(ch, '_' | '-' | ':' | '.')
 }
 
 fn render_token(token: &Token) -> String {
@@ -507,4 +507,12 @@ mod tests {
             ]
         );
     }
+
+    #[test]
+    fn parses_frontend_style_identifiers() {
+        let select = parse_select("SELECT * FROM Employee-Records:2025").unwrap();
+
+        assert_eq!(select.from.len(), 1);
+        assert_eq!(select.from[0].name, "Employee-Records:2025");
+    }
 }