schala/schala-lang/language/src/lib.rs
2019-05-28 03:41:49 -07:00

333 lines
11 KiB
Rust

#![feature(trace_macros)]
#![feature(custom_attribute)]
//#![feature(unrestricted_attribute_tokens)]
#![feature(slice_patterns, box_patterns, box_syntax)]
//! `schala-lang` is where the Schala programming language is actually implemented.
//! It defines the `Schala` type, which contains the state for a Schala REPL, and implements
//! `ProgrammingLanguageInterface` and the chain of compiler passes for it.
extern crate itertools;
#[macro_use]
extern crate lazy_static;
#[macro_use]
extern crate maplit;
extern crate schala_repl;
#[macro_use]
extern crate schala_lang_codegen;
extern crate ena;
use stopwatch::Stopwatch;
use std::time::Duration;
use std::cell::RefCell;
use std::rc::Rc;
use std::collections::HashSet;
use itertools::Itertools;
use schala_repl::{ProgrammingLanguageInterface,
ComputationRequest, ComputationResponse,
LangMetaRequest, LangMetaResponse, GlobalOutputStats,
DebugResponse, DebugAsk};
macro_rules! bx {
($e:expr) => { Box::new($e) }
}
#[macro_use]
mod util;
#[macro_use]
mod typechecking;
mod tokenizing;
mod ast;
mod parsing;
mod symbol_table;
mod builtin;
mod reduced_ast;
mod eval;
/// All bits of 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.
pub struct Schala {
source_reference: SourceReference,
state: eval::State<'static>,
symbol_table: Rc<RefCell<symbol_table::SymbolTable>>,
type_context: typechecking::TypeContext<'static>,
active_parser: Option<parsing::Parser>,
}
impl Schala {
fn handle_docs(&self, source: String) -> LangMetaResponse {
LangMetaResponse::Docs {
doc_string: format!("Schala item `{}` : <<Schala-lang documentation not yet implemented>>", 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 {
source_reference: SourceReference::new(),
symbol_table: symbols.clone(),
state: eval::State::new(symbols),
type_context: typechecking::TypeContext::new(),
active_parser: None,
}
}
/// 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();
let request = ComputationRequest { source: prelude, debug_requests: HashSet::default() };
s.run_computation(request);
s
}
fn handle_debug_immediate(&self, request: DebugAsk) -> DebugResponse {
use DebugAsk::*;
match request {
Timing => DebugResponse { ask: Timing, value: format!("Invalid") },
ByStage { stage_name } => match &stage_name[..] {
"symbol-table" => {
let value = self.symbol_table.borrow().debug_symbol_table();
DebugResponse {
ask: ByStage { stage_name: format!("symbol-table") },
value
}
},
s => {
DebugResponse {
ask: ByStage { stage_name: s.to_string() },
value: format!("Not-implemented")
}
}
}
}
}
}
fn tokenizing(input: &str, _handle: &mut Schala, comp: Option<&mut PassDebugArtifact>) -> Result<Vec<tokenizing::Token>, String> {
let tokens = tokenizing::tokenize(input);
comp.map(|comp| {
let token_string = tokens.iter().map(|t| t.to_string_with_metadata()).join(", ");
comp.add_artifact(token_string);
});
let errors: Vec<String> = tokens.iter().filter_map(|t| t.get_error()).collect();
if errors.len() == 0 {
Ok(tokens)
} else {
Err(format!("{:?}", errors))
}
}
fn parsing(input: Vec<tokenizing::Token>, handle: &mut Schala, comp: Option<&mut PassDebugArtifact>) -> Result<ast::AST, String> {
use crate::parsing::Parser;
let mut parser = match handle.active_parser.take() {
None => Parser::new(input),
Some(parser) => parser
};
let ast = parser.parse();
let _trace = parser.format_parse_trace();
comp.map(|_comp| {
/*
//TODO need to control which of these debug stages get added
let opt = comp.cur_debug_options.get(0).map(|s| s.clone());
match opt {
None => comp.add_artifact(TraceArtifact::new("ast", format!("{:?}", ast))),
Some(ref s) if s == "compact" => comp.add_artifact(TraceArtifact::new("ast", format!("{:?}", ast))),
Some(ref s) if s == "expanded" => comp.add_artifact(TraceArtifact::new("ast", format!("{:#?}", ast))),
Some(ref s) if s == "trace" => comp.add_artifact(TraceArtifact::new_parse_trace(trace)),
Some(ref x) => println!("Bad parsing debug option: {}", x),
};
*/
});
ast.map_err(|err| format_parse_error(err, handle))
}
fn format_parse_error(error: parsing::ParseError, handle: &mut Schala) -> String {
let line_num = error.token.line_num;
let ch = error.token.char_num;
let line_from_program = handle.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);
format!(r#"
{error_msg}
{space_padding} |
{line_num} | {}
{space_padding} | {}
"#, line_from_program, location_pointer, error_msg=error.msg, space_padding=space_padding, line_num=line_num)
}
fn symbol_table(input: ast::AST, handle: &mut Schala, comp: Option<&mut PassDebugArtifact>) -> Result<ast::AST, String> {
let add = handle.symbol_table.borrow_mut().add_top_level_symbols(&input);
match add {
Ok(()) => {
let debug = handle.symbol_table.borrow().debug_symbol_table();
comp.map(|comp| comp.add_artifact(debug));
Ok(input)
},
Err(msg) => Err(msg)
}
}
fn typechecking(input: ast::AST, handle: &mut Schala, comp: Option<&mut PassDebugArtifact>) -> Result<ast::AST, String> {
let result = handle.type_context.typecheck(&input);
comp.map(|comp| {
comp.add_artifact(match result {
Ok(ty) => ty.to_string(),
Err(err) => format!("Type error: {}", err.msg)
});
});
Ok(input)
}
fn ast_reducing(input: ast::AST, handle: &mut Schala, comp: Option<&mut PassDebugArtifact>) -> Result<reduced_ast::ReducedAST, String> {
let ref symbol_table = handle.symbol_table.borrow();
let output = input.reduce(symbol_table);
comp.map(|comp| comp.add_artifact(format!("{:?}", output)));
Ok(output)
}
fn eval(input: reduced_ast::ReducedAST, handle: &mut Schala, comp: Option<&mut PassDebugArtifact>) -> Result<String, String> {
comp.map(|comp| comp.add_artifact(handle.state.debug_print()));
let evaluation_outputs = handle.state.evaluate(input, true);
let text_output: Result<Vec<String>, String> = evaluation_outputs
.into_iter()
.collect();
let eval_output: Result<String, String> = text_output
.map(|v| { v.into_iter().intersperse(format!("\n")).collect() });
eval_output
}
/// Represents lines of source code
struct SourceReference {
lines: Option<Vec<String>>
}
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"))
}
}
#[derive(Default)]
struct PassDebugArtifact {
artifacts: Vec<String>
}
impl PassDebugArtifact {
fn add_artifact(&mut self, artifact: String) {
self.artifacts.push(artifact)
}
}
fn stage_names() -> Vec<&'static str> {
vec![
"tokenizing",
"parsing",
"symbol-table",
"typechecking",
"ast-reduction",
"ast-walking-evaluation"
]
}
impl ProgrammingLanguageInterface for Schala {
fn get_language_name(&self) -> String { format!("Schala") }
fn get_source_file_suffix(&self) -> String { format!("schala") }
fn run_computation(&mut self, request: ComputationRequest) -> ComputationResponse {
struct PassToken<'a> {
schala: &'a mut Schala,
stage_durations: &'a mut Vec<(String, Duration)>,
sw: &'a Stopwatch,
debug_requests: &'a HashSet<DebugAsk>,
debug_responses: &'a mut Vec<DebugResponse>,
}
fn output_wrapper<Input, Output, F>(n: usize, func: F, input: Input, tok: &mut PassToken) -> Result<Output, String>
where F: Fn(Input, &mut Schala, Option<&mut PassDebugArtifact>) -> Result<Output, String>
{
let stage_names = stage_names();
let mut debug_artifact = if tok.debug_requests.contains(&DebugAsk::ByStage { stage_name: stage_names[n].to_string() }) {
Some(PassDebugArtifact::default())
} else {
None
};
let output = func(input, tok.schala, debug_artifact.as_mut());
tok.stage_durations.push((stage_names[n].to_string(), tok.sw.elapsed()));
if let Some(artifact) = debug_artifact {
for value in artifact.artifacts.into_iter() {
let resp = DebugResponse {
ask: DebugAsk::ByStage { stage_name: stage_names[n].to_string() },
value,
};
tok.debug_responses.push(resp);
}
}
output
}
let ComputationRequest { source, debug_requests } = request;
self.source_reference.load_new_source(source);
let sw = Stopwatch::start_new();
let mut stage_durations = Vec::new();
let mut debug_responses = Vec::new();
let mut tok = PassToken { schala: self, stage_durations: &mut stage_durations, sw: &sw, debug_requests: &debug_requests, debug_responses: &mut debug_responses };
let main_output: Result<String, String> = Ok(source)
.and_then(|source| output_wrapper(0, tokenizing, source, &mut tok))
.and_then(|tokens| output_wrapper(1, parsing, tokens, &mut tok))
.and_then(|ast| output_wrapper(2, symbol_table, ast, &mut tok))
.and_then(|ast| output_wrapper(3, typechecking, ast, &mut tok))
.and_then(|ast| output_wrapper(4, ast_reducing, ast, &mut tok))
.and_then(|reduced_ast| output_wrapper(5, eval, reduced_ast, &mut tok));
let total_duration = sw.elapsed();
let global_output_stats = GlobalOutputStats {
total_duration, stage_durations
};
ComputationResponse {
main_output,
global_output_stats,
debug_responses,
}
}
fn request_meta(&mut self, request: LangMetaRequest) -> LangMetaResponse {
match request {
LangMetaRequest::StageNames => LangMetaResponse::StageNames(stage_names().iter().map(|s| s.to_string()).collect()),
LangMetaRequest::Docs { source } => self.handle_docs(source),
LangMetaRequest::ImmediateDebug(debug_request) =>
LangMetaResponse::ImmediateDebug(self.handle_debug_immediate(debug_request)),
LangMetaRequest::Custom { .. } => LangMetaResponse::Custom { kind: format!("not-implemented"), value: format!("") }
}
}
}