use stopwatch::Stopwatch; use std::cell::RefCell; use std::rc::Rc; use schala_repl::{ProgrammingLanguageInterface, ComputationRequest, ComputationResponse, LangMetaRequest, LangMetaResponse, GlobalOutputStats}; use crate::{reduced_ast, tokenizing, parsing, eval, typechecking, symbol_table}; use crate::error::SchalaError; pub type SymbolTableHandle = Rc>; /// All the state necessary to parse and execute a Schala program are stored in this struct. /// `state` represents the execution state for the AST-walking interpreter, the other fields /// should be self-explanatory. #[allow(dead_code)] pub struct Schala { source_reference: SourceReference, state: eval::State<'static>, symbol_table: SymbolTableHandle, resolver: crate::scope_resolution::ScopeResolver<'static>, type_context: typechecking::TypeContext<'static>, active_parser: parsing::Parser, } impl Schala { //TODO implement documentation for language items /* fn handle_docs(&self, source: String) -> LangMetaResponse { LangMetaResponse::Docs { doc_string: format!("Schala item `{}` : <>", source) } } */ } impl Schala { /// Creates a new Schala environment *without* any prelude. fn new_blank_env() -> Schala { let symbols = Rc::new(RefCell::new(symbol_table::SymbolTable::new())); Schala { //TODO maybe these can be the same structure source_reference: SourceReference::new(), symbol_table: symbols.clone(), resolver: crate::scope_resolution::ScopeResolver::new(symbols.clone()), state: eval::State::new(), type_context: typechecking::TypeContext::new(), active_parser: parsing::Parser::new() } } /// Creates a new Schala environment with the standard prelude, which is defined as ordinary /// Schala code in the file `prelude.schala` pub fn new() -> Schala { let prelude = include_str!("../source-files/prelude.schala"); let mut env = Schala::new_blank_env(); let response = env.run_pipeline(prelude); if let Err(err) = response { panic!("Error in prelude, panicking: {}", err.display()); } env } /// This is where the actual action of interpreting/compilation happens. /// Note: this should eventually use a query-based system for parallelization, cf. /// https://rustc-dev-guide.rust-lang.org/overview.html fn run_pipeline(&mut self, source: &str) -> Result { // 1st stage - tokenization // TODO tokenize should return its own error type let tokens = tokenizing::tokenize(source); if let Some(err) = SchalaError::from_tokens(&tokens) { return Err(err) } //2nd stage - parsing self.active_parser.add_new_tokens(tokens); let mut ast = self.active_parser.parse() .map_err(|err| SchalaError::from_parse_error(err, &self.source_reference))?; // Symbol table self.symbol_table.borrow_mut().add_top_level_symbols(&ast) .map_err(|err| SchalaError::from_string(err, Stage::Symbols))?; // Scope resolution - requires mutating AST self.resolver.resolve(&mut ast) .map_err(|err| SchalaError::from_string(err, Stage::ScopeResolution))?; // Typechecking // TODO typechecking not working let _overall_type = self.type_context.typecheck(&ast) .map_err(SchalaError::from_type_error); // Reduce AST - TODO this doesn't produce an error yet, but probably should let symbol_table = self.symbol_table.borrow(); let reduced_ast = reduced_ast::reduce(&ast, &symbol_table); // Tree-walking evaluator. TODO fix this let evaluation_outputs = self.state.evaluate(reduced_ast, true); let text_output: Result, String> = evaluation_outputs .into_iter() .collect(); let text_output: Result, SchalaError> = text_output .map_err(|err| SchalaError::from_string(err, Stage::Evaluation)); let eval_output: String = text_output .map(|v| { Iterator::intersperse(v.into_iter(), "\n".to_owned()).collect() })?; Ok(eval_output) } } /// Represents lines of source code pub(crate) struct SourceReference { lines: Option> } impl SourceReference { fn new() -> SourceReference { SourceReference { lines: None } } fn load_new_source(&mut self, source: &str) { //TODO this is a lot of heap allocations - maybe there's a way to make it more efficient? self.lines = Some(source.lines().map(|s| s.to_string()).collect()); } pub fn get_line(&self, line: usize) -> String { self.lines.as_ref().and_then(|x| x.get(line).map(|s| s.to_string())).unwrap_or(format!("NO LINE FOUND")) } } #[allow(dead_code)] #[derive(Clone, Copy, Debug)] pub(crate) enum Stage { Tokenizing, Parsing, Symbols, ScopeResolution, Typechecking, AstReduction, Evaluation, } fn stage_names() -> Vec<&'static str> { vec![ "tokenizing", "parsing", "symbol-table", "scope-resolution", "typechecking", "ast-reduction", "ast-walking-evaluation" ] } impl ProgrammingLanguageInterface for Schala { type Config = (); fn language_name() -> String { "Schala".to_owned() } fn source_file_suffix() -> String { "schala".to_owned() } fn run_computation(&mut self, request: ComputationRequest) -> ComputationResponse { let ComputationRequest { source, debug_requests: _, config: _ } = request; self.source_reference.load_new_source(source); let sw = Stopwatch::start_new(); let main_output = self.run_pipeline(source) .map_err(|schala_err| schala_err.display()); let global_output_stats = GlobalOutputStats { total_duration: sw.elapsed(), stage_durations: vec![] }; ComputationResponse { main_output, global_output_stats, debug_responses: vec![] } } fn request_meta(&mut self, request: LangMetaRequest) -> LangMetaResponse { match request { LangMetaRequest::StageNames => LangMetaResponse::StageNames(stage_names().iter().map(|s| s.to_string()).collect()), _ => LangMetaResponse::Custom { kind: format!("not-implemented"), value: format!("") } } } }