schala/schala-lang/src/schala.rs
2021-11-14 03:55:35 -08:00

212 lines
7.3 KiB
Rust

use schala_repl::{
ComputationRequest, ComputationResponse, GlobalOutputStats, LangMetaRequest, LangMetaResponse,
ProgrammingLanguageInterface,
};
use stopwatch::Stopwatch;
use crate::{error::SchalaError, parsing, reduced_ir, symbol_table, tree_walk_eval, type_inference};
/// All the state necessary to parse and execute a Schala program are stored in this struct.
pub struct Schala<'a> {
/// Holds a reference to the original source code, parsed into line and character
source_reference: SourceReference,
//state: eval::State<'static>,
/// Keeps track of symbols and scopes
symbol_table: symbol_table::SymbolTable,
/// Contains information for type-checking
type_context: type_inference::TypeContext,
/// Schala Parser
active_parser: parsing::Parser,
/// Execution state for AST-walking interpreter
eval_state: tree_walk_eval::State<'a>,
timings: Vec<(&'static str, std::time::Duration)>,
}
/*
impl Schala {
//TODO implement documentation for language items
/*
fn handle_docs(&self, source: String) -> LangMetaResponse {
LangMetaResponse::Docs {
doc_string: format!("Schala item `{}` : <<Schala-lang documentation not yet implemented>>", source)
}
}
*/
}
*/
impl<'a> Schala<'a> {
/// Creates a new Schala environment *without* any prelude.
fn new_blank_env() -> Schala<'a> {
Schala {
source_reference: SourceReference::new(),
symbol_table: symbol_table::SymbolTable::new(),
type_context: type_inference::TypeContext::new(),
active_parser: parsing::Parser::new(),
eval_state: tree_walk_eval::State::new(),
timings: Vec::new(),
}
}
/// Creates a new Schala environment with the standard prelude, which is defined as ordinary
/// Schala code in the file `prelude.schala`
#[allow(clippy::new_without_default)]
pub fn new() -> Schala<'a> {
let prelude = include_str!("../source-files/prelude.schala");
let mut env = Schala::new_blank_env();
let response = env.run_pipeline(prelude, SchalaConfig::default());
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, config: SchalaConfig) -> Result<String, SchalaError> {
self.timings = vec![];
let sw = Stopwatch::start_new();
self.source_reference.load_new_source(source);
let ast = self
.active_parser
.parse(source)
.map_err(|err| SchalaError::from_parse_error(err, &self.source_reference))?;
self.timings.push(("parsing", sw.elapsed()));
let sw = Stopwatch::start_new();
//Perform all symbol table work
self.symbol_table
.process_ast(&ast, &mut self.type_context)
.map_err(SchalaError::from_symbol_table)?;
self.timings.push(("symbol_table", sw.elapsed()));
// Typechecking
// TODO typechecking not working
//let _overall_type = self.type_context.typecheck(&ast).map_err(SchalaError::from_type_error);
let sw = Stopwatch::start_new();
let reduced_ir = reduced_ir::reduce(&ast, &self.symbol_table, &self.type_context);
self.timings.push(("reduced_ir", sw.elapsed()));
let sw = Stopwatch::start_new();
let evaluation_outputs = self.eval_state.evaluate(reduced_ir, &self.type_context, config.repl);
self.timings.push(("tree-walking-evaluation", sw.elapsed()));
let text_output: Result<Vec<String>, String> = evaluation_outputs.into_iter().collect();
let text_output: Result<Vec<String>, 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 {
last_source: Option<String>,
/// Offsets in *bytes* (not chars) representing a newline character
newline_offsets: Vec<usize>,
}
impl SourceReference {
pub(crate) fn new() -> SourceReference {
SourceReference { last_source: None, newline_offsets: vec![] }
}
pub(crate) fn load_new_source(&mut self, source: &str) {
self.newline_offsets = vec![];
for (offset, ch) in source.as_bytes().iter().enumerate() {
if *ch == b'\n' {
self.newline_offsets.push(offset);
}
}
self.last_source = Some(source.to_string());
}
// (line_start, line_num, the string itself)
pub fn get_line(&self, line: usize) -> (usize, usize, String) {
if self.newline_offsets.is_empty() {
return (0, 0, self.last_source.as_ref().cloned().unwrap());
}
//TODO make sure this is utf8-safe
let start_idx = match self.newline_offsets.binary_search(&line) {
Ok(index) | Err(index) => index,
};
let last_source = self.last_source.as_ref().unwrap();
let start = self.newline_offsets[start_idx];
let end = self.newline_offsets.get(start_idx + 1).cloned().unwrap_or_else(|| last_source.len());
let slice = &last_source.as_bytes()[start..end];
(start, start_idx, std::str::from_utf8(slice).unwrap().to_string())
}
}
#[allow(dead_code)]
#[derive(Clone, Copy, Debug)]
pub(crate) enum Stage {
Parsing,
Symbols,
ScopeResolution,
Typechecking,
AstReduction,
Evaluation,
}
fn stage_names() -> Vec<&'static str> {
vec!["parsing", "symbol-table", "typechecking", "ast-reduction", "ast-walking-evaluation"]
}
#[derive(Default, Clone)]
pub struct SchalaConfig {
pub repl: bool,
}
impl<'a> ProgrammingLanguageInterface for Schala<'a> {
//TODO flesh out Config
type Config = SchalaConfig;
fn language_name() -> String {
"Schala".to_owned()
}
fn source_file_suffix() -> String {
"schala".to_owned()
}
fn run_computation(&mut self, request: ComputationRequest<Self::Config>) -> ComputationResponse {
let ComputationRequest { source, debug_requests: _, config: _ } = request;
let sw = Stopwatch::start_new();
let main_output =
self.run_pipeline(source, request.config).map_err(|schala_err| schala_err.display());
let total_duration = sw.elapsed();
let stage_durations: Vec<_> = std::mem::take(&mut self.timings)
.into_iter()
.map(|(label, duration)| (label.to_string(), duration))
.collect();
let global_output_stats = GlobalOutputStats { total_duration, stage_durations };
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: "not-implemented".to_string(), value: "".to_string() },
}
}
}