improve lua integration by allowing more flexible return types and introducing globals

Cargo.toml

@@ -31,6 +31,7 @@ getset = "0.1.2"
 itertools = "0.13.0"
 mlua = { version = "0.9.7", features = ["lua54", "vendored"], optional = true }
 path-absolutize = "3.1.1"
+pathdiff = "0.2.1"
 serde = { version = "1.0.197", features = ["derive", "rc"], optional = true }
 shulkerbox = { git = "https://github.com/moritz-hoelting/shulkerbox", default-features = false, optional = true, rev = "aff342a64a94981af942223345b5a5f105212957" }
 strsim = "0.11.1"

src/base/log.rs

@@ -291,7 +291,7 @@ fn write_error_line(
                         (line_number == start_line && index >= start_location.column)
                             || (line_number == end_line
                                 && (index + 1)
-                                    < end_location
+                                    <= end_location
                                         .map_or(usize::MAX, |end_location| end_location.column))
                             || (line_number > start_line && line_number < end_line)
                     } else {

src/base/source_file.rs

@@ -136,6 +136,12 @@ impl SourceFile {
             None
         }
     }
+
+    /// Get the relative path of the source file from the current working directory.
+    #[must_use]
+    pub fn path_relative(&self) -> Option<PathBuf> {
+        pathdiff::diff_paths(&self.path, std::env::current_dir().ok()?)
+    }
 }
 
 /// Represents a range of characters in a source file.

src/transpile/error.rs

@@ -128,6 +128,20 @@ impl Display for LuaRuntimeError {
 
 impl std::error::Error for LuaRuntimeError {}
 
+#[cfg(feature = "lua")]
+impl LuaRuntimeError {
+    pub fn from_lua_err(err: &mlua::Error, span: Span) -> Self {
+        let err_string = err.to_string();
+        Self {
+            error_message: err_string
+                .strip_prefix("runtime error: ")
+                .unwrap_or(&err_string)
+                .to_string(),
+            code_block: span,
+        }
+    }
+}
+
 /// An error that occurs when a function declaration is missing.
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub struct UnexpectedExpression(pub Expression);

src/transpile/lua.rs

@@ -2,7 +2,7 @@
 
 #[cfg(feature = "lua")]
 mod enabled {
-    use mlua::Lua;
+    use mlua::{Lua, Value};
 
     use crate::{
         base::{self, source_file::SourceElement, Handler},
@@ -16,7 +16,10 @@ mod enabled {
         /// # Errors
         /// - If Lua code evaluation is disabled.
         #[tracing::instrument(level = "debug", name = "eval_lua", skip_all, ret)]
-        pub fn eval_string(&self, handler: &impl Handler<base::Error>) -> TranspileResult<String> {
+        pub fn eval_string(
+            &self,
+            handler: &impl Handler<base::Error>,
+        ) -> TranspileResult<Option<String>> {
             tracing::debug!("Evaluating Lua code");
 
             let lua = Lua::new();
@@ -24,7 +27,7 @@ mod enabled {
             let name = {
                 let span = self.span();
                 let file = span.source_file();
-                let path = file.path();
+                let path = file.path_relative().unwrap_or_else(|| file.path().clone());
 
                 let start = span.start_location();
                 let end = span.end_location().unwrap_or_else(|| {
@@ -43,24 +46,62 @@ mod enabled {
                 )
             };
 
+            self.add_globals(&lua).unwrap();
+
             let lua_result = lua
                 .load(self.code())
                 .set_name(name)
-                .eval::<String>()
+                .eval::<Value>()
                 .map_err(|err| {
-                    let err_string = err.to_string();
-                    let err = TranspileError::from(LuaRuntimeError {
-                        error_message: err_string
-                            .strip_prefix("runtime error: ")
-                            .unwrap_or(&err_string)
-                            .to_string(),
-                        code_block: self.span(),
-                    });
+                    let err =
+                        TranspileError::from(LuaRuntimeError::from_lua_err(&err, self.span()));
                     handler.receive(crate::Error::from(err.clone()));
                     err
                 })?;
 
-            Ok(lua_result)
+            self.handle_lua_result(dbg!(lua_result)).map_err(|err| {
+                handler.receive(err.clone());
+                err
+            })
+        }
+
+        fn add_globals(&self, lua: &Lua) -> mlua::Result<()> {
+            let globals = lua.globals();
+
+            let location = {
+                let span = self.span();
+                let file = span.source_file();
+                file.path_relative().unwrap_or_else(|| file.path().clone())
+            };
+            globals.set("shu_location", location.to_string_lossy())?;
+
+            Ok(())
+        }
+
+        fn handle_lua_result(&self, value: Value) -> TranspileResult<Option<String>> {
+            match value {
+                Value::Nil => Ok(None),
+                Value::String(s) => Ok(Some(s.to_string_lossy().into_owned())),
+                Value::Integer(i) => Ok(Some(i.to_string())),
+                Value::Number(n) => Ok(Some(n.to_string())),
+                Value::Function(f) => self.handle_lua_result(f.call(()).map_err(|err| {
+                    TranspileError::LuaRuntimeError(LuaRuntimeError::from_lua_err(
+                        &err,
+                        self.span(),
+                    ))
+                })?),
+                Value::Boolean(_)
+                | Value::Error(_)
+                | Value::Table(_)
+                | Value::Thread(_)
+                | Value::UserData(_)
+                | Value::LightUserData(_) => {
+                    Err(TranspileError::LuaRuntimeError(LuaRuntimeError {
+                        code_block: self.span(),
+                        error_message: format!("invalid return type {}", value.type_name()),
+                    }))
+                }
+            }
         }
     }
 }
@@ -79,7 +120,10 @@ mod disabled {
         ///
         /// # Errors
         /// - If Lua code evaluation is disabled.
-        pub fn eval_string(&self, handler: &impl Handler<base::Error>) -> TranspileResult<String> {
+        pub fn eval_string(
+            &self,
+            handler: &impl Handler<base::Error>,
+        ) -> TranspileResult<Option<String>> {
             handler.receive(TranspileError::LuaDisabled);
             tracing::error!("Lua code evaluation is disabled");
             Err(TranspileError::LuaDisabled)

src/transpile/transpiler.rs

@@ -355,7 +355,7 @@ impl Transpiler {
                     Ok(Some(Command::Raw(string.str_content().to_string())))
                 }
                 Expression::Primary(Primary::Lua(code)) => {
-                    Ok(Some(Command::Raw(code.eval_string(handler)?)))
+                    Ok(code.eval_string(handler)?.map(Command::Raw))
                 }
             },
             Statement::Block(_) => {