219 lines
7.4 KiB
Rust
219 lines
7.4 KiB
Rust
#![feature(trace_macros)]
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#![feature(custom_attribute)]
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#![feature(unrestricted_attribute_tokens)]
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#![feature(slice_patterns, box_patterns, box_syntax)]
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//! `schala-lang` is where the Schala programming language is actually implemented.
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//! It defines the `Schala` type, which contains the state for a Schala REPL, and implements
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//! `ProgrammingLanguageInterface` and the chain of compiler passes for it.
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extern crate itertools;
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#[macro_use]
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extern crate lazy_static;
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#[macro_use]
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extern crate maplit;
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extern crate schala_repl;
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#[macro_use]
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extern crate schala_repl_codegen;
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#[macro_use]
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extern crate schala_lang_codegen;
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extern crate ena;
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use std::cell::RefCell;
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use std::rc::Rc;
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use itertools::Itertools;
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use schala_repl::{ProgrammingLanguageInterface, EvalOptions, TraceArtifact, UnfinishedComputation, FinishedComputation};
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macro_rules! bx {
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($e:expr) => { Box::new($e) }
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}
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#[macro_use]
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mod typechecking;
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mod util;
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mod tokenizing;
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mod ast;
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mod parsing;
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mod symbol_table;
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mod builtin;
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mod reduced_ast;
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mod eval;
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//trace_macros!(true);
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#[derive(ProgrammingLanguageInterface)]
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#[LanguageName = "Schala"]
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#[SourceFileExtension = "schala"]
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#[PipelineSteps(load_source, tokenizing, parsing(compact,expanded,trace), symbol_table, typechecking, ast_reducing, eval)]
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#[DocMethod = get_doc]
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#[HandleCustomInterpreterDirectives = handle_custom_interpreter_directives]
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/// All bits of state necessary to parse and execute a Schala program are stored in this struct.
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/// `state` represents the execution state for the AST-walking interpreter, the other fields
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/// should be self-explanatory.
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pub struct Schala {
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source_reference: SourceReference,
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state: eval::State<'static>,
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symbol_table: Rc<RefCell<symbol_table::SymbolTable>>,
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type_context: typechecking::TypeContext<'static>,
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active_parser: Option<parsing::Parser>,
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}
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impl Schala {
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fn get_doc(&self, commands: &Vec<&str>) -> Option<String> {
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Some(format!("Documentation on commands: {:?}", commands))
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}
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fn handle_custom_interpreter_directives(&mut self, commands: &Vec<&str>) -> Option<String> {
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Some(format!("Schala-lang command: {:?} not supported", commands.get(0)))
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}
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}
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impl Schala {
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/// Creates a new Schala environment *without* any prelude.
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fn new_blank_env() -> Schala {
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let symbols = Rc::new(RefCell::new(symbol_table::SymbolTable::new()));
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Schala {
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source_reference: SourceReference::new(),
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symbol_table: symbols.clone(),
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state: eval::State::new(symbols),
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type_context: typechecking::TypeContext::new(),
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active_parser: None,
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}
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}
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/// Creates a new Schala environment with the standard prelude, which is defined as ordinary
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/// Schala code in the file `prelude.schala`
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pub fn new() -> Schala {
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let prelude = include_str!("prelude.schala");
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let mut s = Schala::new_blank_env();
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s.execute_pipeline(prelude, &EvalOptions::default());
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s
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}
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}
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fn load_source<'a>(input: &'a str, handle: &mut Schala, _comp: Option<&mut UnfinishedComputation>) -> Result<&'a str, String> {
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handle.source_reference.load_new_source(input);
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Ok(input)
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}
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fn tokenizing(input: &str, _handle: &mut Schala, comp: Option<&mut UnfinishedComputation>) -> Result<Vec<tokenizing::Token>, String> {
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let tokens = tokenizing::tokenize(input);
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comp.map(|comp| {
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let token_string = tokens.iter().map(|t| t.to_string_with_metadata()).join(", ");
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comp.add_artifact(TraceArtifact::new("tokens", token_string));
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});
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let errors: Vec<String> = tokens.iter().filter_map(|t| t.get_error()).collect();
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if errors.len() == 0 {
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Ok(tokens)
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} else {
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Err(format!("{:?}", errors))
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}
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}
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fn parsing(input: Vec<tokenizing::Token>, handle: &mut Schala, comp: Option<&mut UnfinishedComputation>) -> Result<ast::AST, String> {
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use crate::parsing::Parser;
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let mut parser = match handle.active_parser.take() {
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None => Parser::new(input),
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Some(parser) => parser
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};
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let ast = parser.parse();
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let trace = parser.format_parse_trace();
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comp.map(|comp| {
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//TODO need to control which of these debug stages get added
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let opt = comp.cur_debug_options.get(0).map(|s| s.clone());
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match opt {
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None => comp.add_artifact(TraceArtifact::new("ast", format!("{:?}", ast))),
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Some(ref s) if s == "compact" => comp.add_artifact(TraceArtifact::new("ast", format!("{:?}", ast))),
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Some(ref s) if s == "expanded" => comp.add_artifact(TraceArtifact::new("ast", format!("{:#?}", ast))),
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Some(ref s) if s == "trace" => comp.add_artifact(TraceArtifact::new_parse_trace(trace)),
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Some(ref x) => println!("Bad parsing debug option: {}", x),
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};
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});
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ast.map_err(|err| format_parse_error(err, handle))
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}
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fn format_parse_error(error: parsing::ParseError, handle: &mut Schala) -> String {
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let line_num = error.token.line_num;
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let ch = error.token.char_num;
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let line_from_program = handle.source_reference.get_line(line_num);
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let location_pointer = format!("{}^", " ".repeat(ch));
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let line_num_digits = format!("{}", line_num).chars().count();
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let space_padding = " ".repeat(line_num_digits);
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format!(r#"
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{error_msg}
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{space_padding} |
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{line_num} | {}
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{space_padding} | {}
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"#, line_from_program, location_pointer, error_msg=error.msg, space_padding=space_padding, line_num=line_num)
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}
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fn symbol_table(input: ast::AST, handle: &mut Schala, comp: Option<&mut UnfinishedComputation>) -> Result<ast::AST, String> {
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let add = handle.symbol_table.borrow_mut().add_top_level_symbols(&input);
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match add {
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Ok(()) => {
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let artifact = TraceArtifact::new("symbol_table", handle.symbol_table.borrow().debug_symbol_table());
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comp.map(|comp| comp.add_artifact(artifact));
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Ok(input)
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},
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Err(msg) => Err(msg)
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}
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}
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fn typechecking(input: ast::AST, handle: &mut Schala, comp: Option<&mut UnfinishedComputation>) -> Result<ast::AST, String> {
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let result = handle.type_context.typecheck(&input);
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comp.map(|comp| {
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let artifact = TraceArtifact::new("type", match result {
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Ok(ty) => ty.to_string(),
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Err(err) => format!("Type error: {}", err.msg)
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});
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comp.add_artifact(artifact);
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});
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Ok(input)
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}
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fn ast_reducing(input: ast::AST, handle: &mut Schala, comp: Option<&mut UnfinishedComputation>) -> Result<reduced_ast::ReducedAST, String> {
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let ref symbol_table = handle.symbol_table.borrow();
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let output = input.reduce(symbol_table);
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comp.map(|comp| comp.add_artifact(TraceArtifact::new("ast_reducing", format!("{:?}", output))));
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Ok(output)
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}
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fn eval(input: reduced_ast::ReducedAST, handle: &mut Schala, comp: Option<&mut UnfinishedComputation>) -> Result<String, String> {
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comp.map(|comp| comp.add_artifact(TraceArtifact::new("value_state", handle.state.debug_print())));
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let evaluation_outputs = handle.state.evaluate(input, true);
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let text_output: Result<Vec<String>, String> = evaluation_outputs
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.into_iter()
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.collect();
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let eval_output: Result<String, String> = text_output
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.map(|v| { v.into_iter().intersperse(format!("\n")).collect() });
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eval_output
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}
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/// Represents lines of source code
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struct SourceReference {
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lines: Option<Vec<String>>
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}
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impl SourceReference {
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fn new() -> SourceReference {
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SourceReference { lines: None }
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}
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fn load_new_source(&mut self, source: &str) {
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//TODO this is a lot of heap allocations - maybe there's a way to make it more efficient?
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self.lines = Some(source.lines().map(|s| s.to_string()).collect()); }
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fn get_line(&self, line: usize) -> String {
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self.lines.as_ref().and_then(|x| x.get(line).map(|s| s.to_string())).unwrap_or(format!("NO LINE FOUND"))
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}
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}
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