From 3a85c5fcad786b5ae339ca4b6bd82a9bcb9df4ed Mon Sep 17 00:00:00 2001
From: widberg <widberg@widberg.me>
Date: Thu, 6 Aug 2026 21:00:30 -0400
Subject: [PATCH] Add a TSC executor

---
 README.md          |   1 +
 bff/src/tsc/mod.rs |   6 +
 bff/src/tsc/tsc.rs | 831 +++++++++++++++++++++++++++++++++++++++++++++
 bff/tests/tests.rs |   1 +
 bff/tests/tsc.rs   | 105 ++++++
 5 files changed, 944 insertions(+)
 create mode 100644 bff/src/tsc/tsc.rs
 create mode 100644 bff/tests/tsc.rs

diff --git a/README.md b/README.md
index 08df109..7fea419 100644
--- a/README.md
+++ b/README.md
@@ -60,6 +60,7 @@ A ✔ indicates that the format has been tested and is working. An ❌ indicates
 
 | Format | Status |
 |--------|--------|
+| tsc    | ✔      |
 | csc    | ✔      |
 | psc    | ✔      |
 | CPS    | ✔      |
diff --git a/bff/src/tsc/mod.rs b/bff/src/tsc/mod.rs
index 62b3909..94ec41c 100644
--- a/bff/src/tsc/mod.rs
+++ b/bff/src/tsc/mod.rs
@@ -2,8 +2,14 @@ mod cps;
 mod csc;
 mod mqfel_settings_bin;
 mod psc;
+#[expect(
+    clippy::module_inception,
+    reason = "tsc.rs is the implementation module for the tsc format"
+)]
+mod tsc;
 
 pub use cps::*;
 pub use csc::*;
 pub use mqfel_settings_bin::*;
 pub use psc::*;
+pub use tsc::*;
diff --git a/bff/src/tsc/tsc.rs b/bff/src/tsc/tsc.rs
new file mode 100644
index 0000000..5b4e627
--- /dev/null
+++ b/bff/src/tsc/tsc.rs
@@ -0,0 +1,831 @@
+use std::collections::BTreeSet;
+use std::error::Error;
+use std::path::{Path, PathBuf};
+use std::rc::Rc;
+use std::{fmt, fs};
+
+use encoding_rs::WINDOWS_1252;
+
+// TODO: This should all probably work better with the other tsc formats.
+
+#[derive(Clone, Debug, Default, PartialEq)]
+pub struct Script {
+    pub commands: Vec<Command>,
+}
+
+#[derive(Clone, Debug, PartialEq)]
+pub struct CommandArgument {
+    pub string: String,
+    pub number: Option<f32>,
+}
+
+impl CommandArgument {
+    #[must_use]
+    pub fn new(string: impl Into<String>) -> Self {
+        let string = string.into();
+        let numeric_string = string.strip_suffix('f').unwrap_or(&string);
+        let number = match normalize(numeric_string).as_str() {
+            "TRUE" | "ON" => Some(1.0),
+            "FALSE" | "OFF" => Some(0.0),
+            _ => numeric_string.parse::<f32>().ok(),
+        };
+        Self { string, number }
+    }
+}
+
+#[derive(Clone, Debug, PartialEq)]
+pub struct Command {
+    pub command_name: String,
+    pub arguments: Vec<CommandArgument>,
+    pub line: usize,
+}
+
+#[derive(Clone, Debug)]
+struct Condition {
+    first: String,
+    rest: Vec<(LogicalOperator, String)>,
+}
+
+impl Condition {
+    fn parse(arguments: &[CommandArgument], single_name: bool) -> Result<Self, String> {
+        let Some(first) = arguments.first() else {
+            return Err("conditional directive requires an expression".to_owned());
+        };
+
+        if single_name && arguments.len() != 1 {
+            return Err("conditional directive requires exactly one variable name".to_owned());
+        }
+        if arguments.len().is_multiple_of(2) {
+            return Err("conditional expression must alternate names and operators".to_owned());
+        }
+
+        let mut rest = Vec::new();
+        for [operator, name] in arguments[1..].as_chunks::<2>().0 {
+            let operator = match operator.string.as_str() {
+                "&&" => LogicalOperator::And,
+                "||" => LogicalOperator::Or,
+                _ => {
+                    return Err(format!(
+                        "unknown conditional operator {:?}",
+                        operator.string
+                    ));
+                }
+            };
+            rest.push((operator, name.string.clone()));
+        }
+
+        Ok(Self {
+            first: first.string.clone(),
+            rest,
+        })
+    }
+}
+
+#[derive(Clone, Copy, Debug, PartialEq, Eq)]
+enum LogicalOperator {
+    And,
+    Or,
+}
+
+pub trait ScriptParser {
+    type Script;
+    type Error;
+
+    fn parse(&self, input: &str) -> Result<Self::Script, Self::Error>;
+}
+
+#[derive(Clone, Copy, Debug, Default)]
+pub struct AsoboParser;
+
+impl ScriptParser for AsoboParser {
+    type Script = Script;
+    type Error = ParseError;
+
+    fn parse(&self, input: &str) -> Result<Script, ParseError> {
+        let uncommented = strip_comments(input);
+        let mut commands = Vec::new();
+
+        for (line_index, line) in uncommented.lines().enumerate() {
+            let line_number = line_index + 1;
+            let arguments = tokenize(line, line_number)?;
+            let Some((name, arguments)) = arguments.split_first() else {
+                continue;
+            };
+
+            commands.push(Command {
+                command_name: name.string.clone(),
+                arguments: arguments.to_vec(),
+                line: line_number,
+            });
+        }
+
+        Ok(Script { commands })
+    }
+}
+
+#[derive(Clone, Debug, PartialEq, Eq)]
+pub struct ParseError {
+    pub line: usize,
+    pub message: String,
+}
+
+impl fmt::Display for ParseError {
+    fn fmt(&self, formatter: &mut fmt::Formatter<'_>) -> fmt::Result {
+        write!(formatter, "line {}: {}", self.line, self.message)
+    }
+}
+
+impl Error for ParseError {}
+
+pub trait ScriptExecutor<S> {
+    type Error;
+
+    fn execute(&mut self, script: &S) -> Result<(), Self::Error>;
+}
+
+pub trait ScriptLoader {
+    fn load(&self, path: &Path) -> std::io::Result<String>;
+}
+
+#[derive(Clone, Debug)]
+pub struct FileSystemScriptLoader {
+    root: PathBuf,
+}
+
+impl FileSystemScriptLoader {
+    #[must_use]
+    pub fn new(root: impl Into<PathBuf>) -> Self {
+        Self { root: root.into() }
+    }
+
+    #[must_use]
+    pub fn root(&self) -> &Path {
+        &self.root
+    }
+}
+
+impl ScriptLoader for FileSystemScriptLoader {
+    fn load(&self, path: &Path) -> std::io::Result<String> {
+        let bytes = fs::read(self.root.join(path))?;
+        Ok(WINDOWS_1252.decode(&bytes).0.into_owned())
+    }
+}
+
+pub type CommandCallback<P, L, U> =
+    Rc<dyn Fn(&mut AsoboExecutor<P, L, U>, &Command) -> Result<(), ExecutionError>>;
+
+#[derive(Clone, Debug, PartialEq, Eq)]
+pub struct CommandKey {
+    pub full_name: String,
+    pub short_name: String,
+}
+
+impl CommandKey {
+    #[must_use]
+    pub fn new(command_name: impl AsRef<str>) -> Self {
+        let command_name = command_name.as_ref();
+        Self {
+            full_name: normalize(command_name),
+            short_name: command_name
+                .chars()
+                .filter(|character| character.is_ascii_uppercase() || character.is_ascii_digit())
+                .take(15)
+                .collect(),
+        }
+    }
+
+    fn matches(&self, command_name: &str) -> bool {
+        command_name == self.full_name
+            || (!self.short_name.is_empty() && command_name == self.short_name)
+    }
+}
+
+#[derive(Debug)]
+pub enum ExecutionError {
+    Parse {
+        path: PathBuf,
+        source: ParseError,
+    },
+    Io {
+        path: PathBuf,
+        source: std::io::Error,
+    },
+    MissingSourcePath {
+        command: String,
+        line: usize,
+    },
+    InvalidDirective {
+        command: String,
+        line: usize,
+        message: String,
+    },
+    UnmatchedElse {
+        line: usize,
+    },
+    DuplicateElse {
+        line: usize,
+    },
+    UnmatchedEndIf {
+        line: usize,
+    },
+    UnterminatedIf,
+}
+
+impl fmt::Display for ExecutionError {
+    fn fmt(&self, formatter: &mut fmt::Formatter<'_>) -> fmt::Result {
+        match self {
+            Self::Parse { path, source } => {
+                write!(formatter, "failed to parse {}: {source}", path.display())
+            }
+            Self::Io { path, source } => {
+                write!(formatter, "failed to load {}: {source}", path.display())
+            }
+            Self::MissingSourcePath { command, line } => {
+                write!(formatter, "line {line}: {command} requires a script path")
+            }
+            Self::InvalidDirective {
+                command,
+                line,
+                message,
+            } => write!(formatter, "line {line}: invalid {command}: {message}"),
+            Self::UnmatchedElse { line } => write!(formatter, "line {line}: #else without #if"),
+            Self::DuplicateElse { line } => write!(formatter, "line {line}: duplicate #else"),
+            Self::UnmatchedEndIf { line } => write!(formatter, "line {line}: #endif without #if"),
+            Self::UnterminatedIf => formatter.write_str("script ended before #endif"),
+        }
+    }
+}
+
+impl Error for ExecutionError {
+    fn source(&self) -> Option<&(dyn Error + 'static)> {
+        match self {
+            Self::Parse { source, .. } => Some(source),
+            Self::Io { source, .. } => Some(source),
+            _ => None,
+        }
+    }
+}
+
+#[derive(Clone, Debug)]
+enum ExecutionFrame {
+    CommandLine,
+    Script {
+        path: PathBuf,
+        arguments: Vec<String>,
+    },
+}
+
+#[derive(Clone, Copy, Debug)]
+struct ConditionalFrame {
+    parent_active: bool,
+    condition: bool,
+    active: bool,
+    saw_else: bool,
+}
+
+pub struct AsoboExecutor<P = AsoboParser, L = FileSystemScriptLoader, U = ()> {
+    parser: P,
+    loader: L,
+    variables: BTreeSet<String>,
+    user_data: U,
+    handlers: Vec<(CommandKey, CommandCallback<P, L, U>)>,
+    default_callback: Option<CommandCallback<P, L, U>>,
+}
+
+impl<L> AsoboExecutor<AsoboParser, L, ()>
+where
+    L: ScriptLoader,
+{
+    #[must_use]
+    pub fn new(loader: L) -> Self {
+        Self::with_parser(AsoboParser, loader)
+    }
+}
+
+impl<L, U> AsoboExecutor<AsoboParser, L, U>
+where
+    L: ScriptLoader,
+{
+    #[must_use]
+    pub fn with_user_data(loader: L, user_data: U) -> Self {
+        Self::with_parser_and_user_data(AsoboParser, loader, user_data)
+    }
+}
+
+impl<P, L, U> AsoboExecutor<P, L, U> {
+    pub fn set_variable(&mut self, name: impl AsRef<str>) {
+        self.variables.insert(normalize(name.as_ref()));
+    }
+
+    pub fn unset_variable(&mut self, name: impl AsRef<str>) {
+        self.variables.remove(&normalize(name.as_ref()));
+    }
+
+    #[must_use]
+    pub fn has_variable(&self, name: impl AsRef<str>) -> bool {
+        self.variables.contains(&normalize(name.as_ref()))
+    }
+
+    pub fn variables(&self) -> impl Iterator<Item = &str> {
+        self.variables.iter().map(String::as_str)
+    }
+
+    #[must_use]
+    pub const fn user_data(&self) -> &U {
+        &self.user_data
+    }
+
+    #[must_use]
+    pub const fn user_data_mut(&mut self) -> &mut U {
+        &mut self.user_data
+    }
+
+    #[must_use]
+    pub fn into_user_data(self) -> U {
+        self.user_data
+    }
+
+    pub fn on_command<F>(&mut self, command_name: impl AsRef<str>, callback: F)
+    where
+        F: Fn(&mut Self, &Command) -> Result<(), ExecutionError> + 'static,
+    {
+        self.handlers
+            .push((CommandKey::new(command_name), Rc::new(callback)));
+    }
+
+    pub fn remove_command(&mut self, command_name: impl AsRef<str>) -> bool {
+        let command_name = normalize(command_name);
+        let Some(index) = self
+            .handlers
+            .iter()
+            .rposition(|(key, _)| key.matches(&command_name))
+        else {
+            return false;
+        };
+        self.handlers.remove(index);
+        true
+    }
+
+    pub fn on_default<F>(&mut self, callback: F)
+    where
+        F: Fn(&mut Self, &Command) -> Result<(), ExecutionError> + 'static,
+    {
+        self.default_callback = Some(Rc::new(callback));
+    }
+
+    pub fn remove_default(&mut self) -> bool {
+        self.default_callback.take().is_some()
+    }
+}
+
+impl<P, L> AsoboExecutor<P, L, ()>
+where
+    P: ScriptParser<Script = Script, Error = ParseError>,
+    L: ScriptLoader,
+{
+    #[must_use]
+    pub fn with_parser(parser: P, loader: L) -> Self {
+        Self::with_parser_and_user_data(parser, loader, ())
+    }
+}
+
+impl<P, L, U> AsoboExecutor<P, L, U>
+where
+    P: ScriptParser<Script = Script, Error = ParseError>,
+    L: ScriptLoader,
+{
+    #[must_use]
+    pub fn with_parser_and_user_data(parser: P, loader: L, user_data: U) -> Self {
+        let mut executor = Self {
+            parser,
+            loader,
+            variables: BTreeSet::new(),
+            user_data,
+            handlers: Vec::new(),
+            default_callback: None,
+        };
+        executor.register_default_handlers();
+        executor
+    }
+
+    pub fn execute_file(&mut self, path: impl Into<PathBuf>) -> Result<(), ExecutionError> {
+        self.execute_loaded(path.into(), Vec::new())
+    }
+
+    pub fn execute_script_text(
+        &mut self,
+        name: impl Into<PathBuf>,
+        text: &str,
+        arguments: impl IntoIterator<Item = impl Into<String>>,
+    ) -> Result<(), ExecutionError> {
+        let path = name.into();
+        let script = self
+            .parser
+            .parse(text)
+            .map_err(|source| ExecutionError::Parse {
+                path: path.clone(),
+                source,
+            })?;
+        let frame = ExecutionFrame::Script {
+            path,
+            arguments: arguments.into_iter().map(Into::into).collect(),
+        };
+        self.execute_script(&script, &frame)
+    }
+
+    pub fn execute_command_line(&mut self, line: &str) -> Result<(), ExecutionError> {
+        let script = self
+            .parser
+            .parse(line)
+            .map_err(|source| ExecutionError::Parse {
+                path: PathBuf::from("<command line>"),
+                source,
+            })?;
+        self.execute_script(&script, &ExecutionFrame::CommandLine)
+    }
+
+    fn execute_loaded(
+        &mut self,
+        path: PathBuf,
+        arguments: Vec<String>,
+    ) -> Result<(), ExecutionError> {
+        let text = self
+            .loader
+            .load(&path)
+            .map_err(|source| ExecutionError::Io {
+                path: path.clone(),
+                source,
+            })?;
+        let script = self
+            .parser
+            .parse(&text)
+            .map_err(|source| ExecutionError::Parse {
+                path: path.clone(),
+                source,
+            })?;
+        self.execute_script(&script, &ExecutionFrame::Script { path, arguments })
+    }
+
+    fn execute_script(
+        &mut self,
+        script: &Script,
+        frame: &ExecutionFrame,
+    ) -> Result<(), ExecutionError> {
+        let mut conditionals = Vec::new();
+
+        for command in &script.commands {
+            let command = expand_command(command, frame);
+            if is_asobo_directive(&command.command_name) {
+                self.execute_directive(&command, &mut conditionals)?;
+            } else if is_active(&conditionals) {
+                self.execute_command(command)?;
+            }
+        }
+
+        if conditionals.is_empty() {
+            Ok(())
+        } else {
+            Err(ExecutionError::UnterminatedIf)
+        }
+    }
+
+    fn execute_directive(
+        &mut self,
+        command: &Command,
+        conditionals: &mut Vec<ConditionalFrame>,
+    ) -> Result<(), ExecutionError> {
+        match normalize(&command.command_name).as_str() {
+            "#SET" if is_active(conditionals) => {
+                let name = exactly_one_argument(command)?;
+                self.set_variable(&name.string);
+            }
+            "#UNSET" if is_active(conditionals) => {
+                let name = exactly_one_argument(command)?;
+                self.unset_variable(&name.string);
+            }
+            "#IF" | "#IFDEF" | "#IFNOT" | "#IFNDEF" => {
+                let parent_active = is_active(conditionals);
+                let mut value = self.evaluate(
+                    &Condition::parse(
+                        &command.arguments,
+                        matches!(
+                            normalize(&command.command_name).as_str(),
+                            "#IFDEF" | "#IFNOT" | "#IFNDEF"
+                        ),
+                    )
+                    .map_err(|message| invalid_directive(command, message))?,
+                );
+                if matches!(
+                    normalize(&command.command_name).as_str(),
+                    "#IFNOT" | "#IFNDEF"
+                ) {
+                    value = !value;
+                }
+                conditionals.push(ConditionalFrame {
+                    parent_active,
+                    condition: value,
+                    active: parent_active && value,
+                    saw_else: false,
+                });
+            }
+            "#ELSE" => {
+                require_no_arguments(command)?;
+                let Some(conditional) = conditionals.last_mut() else {
+                    return Err(ExecutionError::UnmatchedElse { line: command.line });
+                };
+                if conditional.saw_else {
+                    return Err(ExecutionError::DuplicateElse { line: command.line });
+                }
+                conditional.saw_else = true;
+                conditional.active = conditional.parent_active && !conditional.condition;
+            }
+            "#ENDIF" => {
+                require_no_arguments(command)?;
+                if conditionals.pop().is_none() {
+                    return Err(ExecutionError::UnmatchedEndIf { line: command.line });
+                }
+            }
+            "#DEFINE" if is_active(conditionals) => {
+                let Some((command_name, arguments)) = command.arguments.split_first() else {
+                    return Err(invalid_directive(command, "requires a command"));
+                };
+                self.execute_command(Command {
+                    command_name: command_name.string.clone(),
+                    arguments: arguments.to_vec(),
+                    line: command.line,
+                })?;
+            }
+            "#SET" | "#UNSET" | "#DEFINE" => {}
+            _ => unreachable!("only Asobo directives are sent to execute_directive"),
+        }
+
+        Ok(())
+    }
+
+    fn evaluate(&self, condition: &Condition) -> bool {
+        let mut value = self.has_variable(&condition.first);
+        for (operator, name) in &condition.rest {
+            let next = self.has_variable(name);
+            value = match operator {
+                LogicalOperator::And => value && next,
+                LogicalOperator::Or => value || next,
+            };
+        }
+        value
+    }
+
+    fn execute_command(&mut self, command: Command) -> Result<(), ExecutionError> {
+        let name = normalize(&command.command_name);
+        if let Some(handler) = self
+            .handlers
+            .iter()
+            .rev()
+            .find(|(key, _)| key.matches(&name))
+            .map(|(_, handler)| Rc::clone(handler))
+        {
+            return handler(self, &command);
+        }
+
+        if let Some(callback) = self.default_callback.clone() {
+            callback(self, &command)?;
+        }
+
+        Ok(())
+    }
+
+    fn register_default_handlers(&mut self) {
+        self.on_command("SouRCe", |executor, command| {
+            executor.execute_source_command(command)
+        });
+        self.on_command("BSouRCe", |executor, command| {
+            executor.execute_source_command(command)
+        });
+    }
+
+    fn execute_source_command(&mut self, command: &Command) -> Result<(), ExecutionError> {
+        let Some(path) = command.arguments.first() else {
+            return Err(ExecutionError::MissingSourcePath {
+                command: command.command_name.clone(),
+                line: command.line,
+            });
+        };
+        let arguments = command.arguments[1..]
+            .iter()
+            .map(|argument| argument.string.clone())
+            .collect();
+        self.execute_loaded(PathBuf::from(path.string.replace('\\', "/")), arguments)
+    }
+}
+
+impl<P, L, U> ScriptExecutor<Script> for AsoboExecutor<P, L, U>
+where
+    P: ScriptParser<Script = Script, Error = ParseError>,
+    L: ScriptLoader,
+{
+    type Error = ExecutionError;
+
+    fn execute(&mut self, script: &Script) -> Result<(), Self::Error> {
+        self.execute_script(script, &ExecutionFrame::CommandLine)
+    }
+}
+
+fn is_asobo_directive(command_name: &str) -> bool {
+    matches!(
+        normalize(command_name).as_str(),
+        "#SET"
+            | "#UNSET"
+            | "#IF"
+            | "#IFDEF"
+            | "#IFNOT"
+            | "#IFNDEF"
+            | "#ELSE"
+            | "#ENDIF"
+            | "#DEFINE"
+    )
+}
+
+fn invalid_directive(command: &Command, message: impl Into<String>) -> ExecutionError {
+    ExecutionError::InvalidDirective {
+        command: command.command_name.clone(),
+        line: command.line,
+        message: message.into(),
+    }
+}
+
+fn exactly_one_argument(command: &Command) -> Result<&CommandArgument, ExecutionError> {
+    if command.arguments.len() == 1 {
+        Ok(&command.arguments[0])
+    } else {
+        Err(invalid_directive(command, "requires exactly one argument"))
+    }
+}
+
+fn require_no_arguments(command: &Command) -> Result<(), ExecutionError> {
+    if command.arguments.is_empty() {
+        Ok(())
+    } else {
+        Err(invalid_directive(command, "does not accept arguments"))
+    }
+}
+
+fn strip_comments(input: &str) -> String {
+    let mut output = String::with_capacity(input.len());
+    let mut characters = input.chars().peekable();
+    let mut in_block_comment = false;
+    let mut in_quote = false;
+
+    while let Some(character) = characters.next() {
+        if in_block_comment {
+            if character == '*' && characters.peek() == Some(&'/') {
+                characters.next();
+                in_block_comment = false;
+            } else if character == '\n' {
+                output.push('\n');
+            }
+            continue;
+        }
+
+        if in_quote {
+            output.push(character);
+            if character == '\\' && characters.peek() == Some(&'"') {
+                output.push(characters.next().expect("peeked quote must exist"));
+            } else if character == '"' {
+                in_quote = false;
+            }
+            continue;
+        }
+
+        match character {
+            '"' => {
+                in_quote = true;
+                output.push(character);
+            }
+            '/' if characters.peek() == Some(&'*') => {
+                characters.next();
+                in_block_comment = true;
+            }
+            '/' if characters.peek() == Some(&'/') => {
+                characters.next();
+                for next in characters.by_ref() {
+                    if next == '\n' {
+                        output.push('\n');
+                        break;
+                    }
+                }
+            }
+            _ => output.push(character),
+        }
+    }
+
+    output
+}
+
+fn tokenize(line: &str, line_number: usize) -> Result<Vec<CommandArgument>, ParseError> {
+    let mut arguments = Vec::new();
+    let mut current = String::new();
+    let mut characters = line.chars().peekable();
+    let mut in_quote = false;
+    let mut token_started = false;
+
+    while let Some(character) = characters.next() {
+        match character {
+            '"' => {
+                in_quote = !in_quote;
+                token_started = true;
+            }
+            '\\' if in_quote && characters.peek() == Some(&'"') => {
+                current.push(characters.next().expect("peeked quote must exist"));
+                token_started = true;
+            }
+            ' ' | '\t' if !in_quote => {
+                if token_started {
+                    arguments.push(CommandArgument::new(std::mem::take(&mut current)));
+                    token_started = false;
+                }
+            }
+            _ => {
+                current.push(character);
+                token_started = true;
+            }
+        }
+    }
+
+    if in_quote {
+        return Err(ParseError {
+            line: line_number,
+            message: "unterminated quoted string".to_owned(),
+        });
+    }
+    if token_started {
+        arguments.push(CommandArgument::new(current));
+    }
+    Ok(arguments)
+}
+
+fn normalize(value: impl AsRef<str>) -> String {
+    value.as_ref().to_ascii_uppercase()
+}
+
+fn is_active(conditionals: &[ConditionalFrame]) -> bool {
+    conditionals
+        .last()
+        .is_none_or(|conditional| conditional.active)
+}
+
+fn expand_command(command: &Command, frame: &ExecutionFrame) -> Command {
+    Command {
+        command_name: expand(&command.command_name, frame),
+        arguments: command
+            .arguments
+            .iter()
+            .map(|argument| CommandArgument::new(expand(&argument.string, frame)))
+            .collect(),
+        line: command.line,
+    }
+}
+
+fn expand(value: &str, frame: &ExecutionFrame) -> String {
+    let ExecutionFrame::Script { path, arguments } = frame else {
+        return value.to_owned();
+    };
+
+    let mut output = String::with_capacity(value.len());
+    let mut characters = value.chars().peekable();
+
+    while let Some(character) = characters.next() {
+        if character != '%' {
+            output.push(character);
+            continue;
+        }
+
+        let mut index = String::new();
+        while let Some(next) = characters.peek() {
+            if next.is_ascii_digit() {
+                index.push(*next);
+                characters.next();
+            } else {
+                break;
+            }
+        }
+        if index.is_empty() {
+            output.push('%');
+            continue;
+        }
+
+        match index.parse::<usize>() {
+            Ok(0) => output.push_str(
+                path.file_name()
+                    .and_then(|name| name.to_str())
+                    .unwrap_or_default(),
+            ),
+            Ok(index) => {
+                if let Some(argument) = arguments.get(index - 1) {
+                    output.push_str(argument);
+                }
+            }
+            Err(_) => output.push('%'),
+        }
+    }
+
+    output
+}
diff --git a/bff/tests/tests.rs b/bff/tests/tests.rs
index a66b533..e014fc0 100644
--- a/bff/tests/tests.rs
+++ b/bff/tests/tests.rs
@@ -10,3 +10,4 @@ mod bigfile;
 mod cps;
 mod mqfel_settings;
 mod path_helpers;
+mod tsc;
diff --git a/bff/tests/tsc.rs b/bff/tests/tsc.rs
new file mode 100644
index 0000000..acd982c
--- /dev/null
+++ b/bff/tests/tsc.rs
@@ -0,0 +1,105 @@
+use std::collections::HashMap;
+
+use bff::tsc::{AsoboExecutor, FileSystemScriptLoader};
+
+use crate::path_helpers::resolve_repo_data_path;
+
+#[derive(Default)]
+struct TestData {
+    seen_commands: HashMap<String, usize>,
+    default_callback_count: usize,
+    inline_commands: usize,
+}
+
+#[test]
+fn remove_command_handler() {
+    let mut executor =
+        AsoboExecutor::with_user_data(FileSystemScriptLoader::new("unused"), Vec::<u32>::new());
+    executor.on_command("GiveMoney1000", |executor, _command| {
+        executor.user_data_mut().push(1);
+        Ok(())
+    });
+    executor.on_command("GiveMoney1000", |executor, _command| {
+        executor.user_data_mut().push(2);
+        Ok(())
+    });
+
+    executor.execute_command_line("GM1000").unwrap();
+    assert!(executor.remove_command("GM1000"));
+    executor.execute_command_line("GiveMoney1000").unwrap();
+    assert!(executor.remove_command("givemoney1000"));
+    assert!(!executor.remove_command("GM1000"));
+    executor.execute_command_line("GM1000").unwrap();
+
+    assert_eq!(executor.into_user_data(), vec![2, 1]);
+}
+
+#[test]
+fn remove_default_handler() {
+    let mut executor = AsoboExecutor::with_user_data(FileSystemScriptLoader::new("unused"), 0usize);
+    executor.on_default(|executor, _command| {
+        *executor.user_data_mut() += 1;
+        Ok(())
+    });
+
+    executor.execute_command_line("Unknown").unwrap();
+    assert!(executor.remove_default());
+    executor.execute_command_line("Unknown").unwrap();
+    assert!(!executor.remove_default());
+
+    assert_eq!(executor.into_user_data(), 1);
+}
+
+#[test]
+fn execute_asobo_tsc_sample() {
+    let root = resolve_repo_data_path("FUEL_tsc_sample");
+    let mut executor =
+        AsoboExecutor::with_user_data(FileSystemScriptLoader::new(root), TestData::default());
+    executor.on_command("InlineCommand", |executor, _command| {
+        executor.user_data_mut().inline_commands += 1;
+        Ok(())
+    });
+    executor.on_default(|executor, command| {
+        let data = executor.user_data_mut();
+        data.default_callback_count += 1;
+        *data
+            .seen_commands
+            .entry(command.command_name.clone())
+            .or_default() += 1;
+        Ok(())
+    });
+
+    executor.execute_command_line("#set _PC").unwrap();
+    executor
+        .execute_script_text(
+            "initial_state_multiline.tsc",
+            r#"
+#set _MASTER
+#if _PC && _MASTER
+IC "quoted // text and /* text are part of this argument"
+#endif
+#set _BIGFILE
+"#,
+            Vec::<String>::new(),
+        )
+        .unwrap();
+    executor.execute_command_line("SRC Vibrations.tsc").unwrap();
+    executor.execute_command_line("BSRC user.tsc").unwrap();
+
+    let has_pc = executor.has_variable("_PC");
+    let has_master = executor.has_variable("_MASTER");
+    let has_bigfile = executor.has_variable("_BIGFILE");
+    let data = executor.into_user_data();
+    eprintln!(
+        "Asobo TSC callback activity: {} commands across {} names",
+        data.default_callback_count,
+        data.seen_commands.len(),
+    );
+
+    assert!(has_pc);
+    assert!(has_master);
+    assert!(has_bigfile);
+    assert_eq!(data.inline_commands, 1);
+    assert!(data.default_callback_count > 100);
+    assert!(!data.seen_commands.is_empty());
+}