use stopwatch::Stopwatch; use std::cell::RefCell; use std::rc::Rc; use std::collections::HashSet; use schala_repl::{ProgrammingLanguageInterface, ComputationRequest, ComputationResponse, LangMetaRequest, LangMetaResponse, GlobalOutputStats}; use crate::{reduced_ast, tokenizing, parsing, eval, typechecking, symbol_table, source_map}; pub type SymbolTableHandle = Rc>; pub type SourceMapHandle = 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, source_map: SourceMapHandle, 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 source_map = Rc::new(RefCell::new(source_map::SourceMap::new())); let symbols = Rc::new(RefCell::new(symbol_table::SymbolTable::new(source_map.clone()))); Schala { //TODO maybe these can be the same structure source_reference: SourceReference::new(), symbol_table: symbols.clone(), source_map: source_map.clone(), resolver: crate::scope_resolution::ScopeResolver::new(symbols.clone()), state: eval::State::new(), type_context: typechecking::TypeContext::new(), active_parser: parsing::Parser::new(source_map) } } /// 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!("prelude.schala"); let mut s = Schala::new_blank_env(); //TODO this shouldn't depend on schala-repl types let request = ComputationRequest { source: prelude, debug_requests: HashSet::default() }; let response = s.run_computation(request); if let Err(msg) = response.main_output { panic!("Error in prelude, panicking: {}", msg); } s } /// 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 { //TODO `run_pipeline` should return a formatted error struct //TODO every stage should have a common error-format that gets turned into a repl-appropriate //string in `run_computation` // 1st stage - tokenization // TODO tokenize should return its own error type let tokens = tokenizing::tokenize(source); let token_errors: Vec = tokens.iter().filter_map(|t| t.get_error()).collect(); if token_errors.len() > 0 { return Err(format!("{:?}", token_errors)); } //2nd stage - parsing self.active_parser.add_new_tokens(tokens); let mut ast = self.active_parser.parse() .map_err(|err| format_parse_error(err, &self.source_reference))?; // Symbol table self.symbol_table.borrow_mut().add_top_level_symbols(&ast)?; // Scope resolution - requires mutating AST self.resolver.resolve(&mut ast)?; // Typechecking // TODO typechecking not working let _overall_type = self.type_context.typecheck(&ast) .map_err(|err| format!("Type error: {}", err.msg)); // Reduce AST - 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 eval_output: String = text_output .map(|v| { Iterator::intersperse(v.into_iter(), "\n".to_owned()).collect() })?; Ok(eval_output) } } fn format_parse_error(error: parsing::ParseError, source_reference: &SourceReference) -> String { let line_num = error.token.location.line_num; let ch = error.token.location.char_num; let line_from_program = source_reference.get_line(line_num); let location_pointer = format!("{}^", " ".repeat(ch)); let line_num_digits = format!("{}", line_num).chars().count(); let space_padding = " ".repeat(line_num_digits); let production = match error.production_name { Some(n) => format!("\n(from production \"{}\")", n), None => "".to_string() }; format!(r#" {error_msg}{production} {space_padding} | {line_num} | {} {space_padding} | {} "#, line_from_program, location_pointer, error_msg=error.msg, space_padding=space_padding, line_num=line_num, production=production ) } /// Represents lines of source code 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()); } 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")) } } fn stage_names() -> Vec<&'static str> { vec![ "tokenizing", "parsing", "symbol-table", "scope-resolution", "typechecking", "ast-reduction", "ast-walking-evaluation" ] } impl ProgrammingLanguageInterface for Schala { 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: _ } = request; self.source_reference.load_new_source(source); let sw = Stopwatch::start_new(); let main_output = self.run_pipeline(source); 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!("") } } } }