schala/schala-lang/language/src/lib.rs
2018-11-11 18:04:44 -08:00

172 lines
5.9 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_repl_codegen;
#[macro_use]
extern crate schala_lang_codegen;
use std::cell::RefCell;
use std::rc::Rc;
use itertools::Itertools;
use schala_repl::{ProgrammingLanguageInterface, EvalOptions, TraceArtifact, UnfinishedComputation, FinishedComputation};
macro_rules! bx {
($e:expr) => { Box::new($e) }
}
mod util;
mod builtin;
mod tokenizing;
mod ast;
mod parsing;
mod symbol_table;
mod typechecking;
mod reduced_ast;
mod eval;
//trace_macros!(true);
#[derive(ProgrammingLanguageInterface)]
#[LanguageName = "Schala"]
#[SourceFileExtension = "schala"]
#[PipelineSteps(tokenizing, parsing(compact,expanded,trace), symbol_table, typechecking, ast_reducing, eval)]
#[DocMethod = get_doc]
#[HandleCustomInterpreterDirectives = handle_custom_interpreter_directives]
/// 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 {
state: eval::State<'static>,
symbol_table: Rc<RefCell<symbol_table::SymbolTable>>,
type_context: typechecking::TypeContext<'static>,
active_parser: Option<parsing::Parser>,
}
impl Schala {
fn get_doc(&self, commands: &Vec<&str>) -> Option<String> {
Some(format!("Documentation on commands: {:?}", commands))
}
fn handle_custom_interpreter_directives(&mut self, commands: &Vec<&str>) -> Option<String> {
Some(format!("Schala-lang command: {:?} not supported", commands.get(0)))
}
}
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 {
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();
s.execute_pipeline(prelude, &EvalOptions::default());
s
}
}
fn tokenizing(_handle: &mut Schala, input: &str, comp: Option<&mut UnfinishedComputation>) -> Result<Vec<tokenizing::Token>, String> {
let tokens = tokenizing::tokenize(input);
comp.map(|comp| {
let token_string = tokens.iter().map(|t| format!("{:?}<L:{},C:{}>", t.token_type, t.offset.0, t.offset.1)).join(", ");
comp.add_artifact(TraceArtifact::new("tokens", 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(handle: &mut Schala, input: Vec<tokenizing::Token>, comp: Option<&mut UnfinishedComputation>) -> Result<ast::AST, String> {
use 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| err.msg)
}
fn symbol_table(handle: &mut Schala, input: ast::AST, comp: Option<&mut UnfinishedComputation>) -> Result<ast::AST, String> {
let add = handle.symbol_table.borrow_mut().add_top_level_symbols(&input);
match add {
Ok(()) => {
let artifact = TraceArtifact::new("symbol_table", handle.symbol_table.borrow().debug_symbol_table());
comp.map(|comp| comp.add_artifact(artifact));
Ok(input)
},
Err(msg) => Err(msg)
}
}
fn typechecking(handle: &mut Schala, input: ast::AST, comp: Option<&mut UnfinishedComputation>) -> Result<ast::AST, String> {
let result = handle.type_context.typecheck(&input);
comp.map(|comp| {
let artifact = TraceArtifact::new("type", format!("{:?}", result));
comp.add_artifact(artifact);
});
Ok(input)
}
fn ast_reducing(handle: &mut Schala, input: ast::AST, comp: Option<&mut UnfinishedComputation>) -> 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(TraceArtifact::new("ast_reducing", format!("{:?}", output))));
Ok(output)
}
fn eval(handle: &mut Schala, input: reduced_ast::ReducedAST, comp: Option<&mut UnfinishedComputation>) -> Result<String, String> {
comp.map(|comp| comp.add_artifact(TraceArtifact::new("value_state", 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
}