Files
scryer-prolog/src/machine/term_stream.rs
2021-02-16 22:08:32 -07:00

149 lines
4.0 KiB
Rust

use prolog_parser::ast::*;
use prolog_parser::parser::*;
use crate::machine::machine_errors::CompilationError;
use crate::machine::*;
use indexmap::IndexSet;
use std::collections::VecDeque;
use std::fmt;
pub(crate) trait TermStream: Sized {
type Evacuable;
fn next(&mut self, op_dir: &CompositeOpDir) -> Result<Term, CompilationError>;
fn eof(&mut self) -> Result<bool, CompilationError>;
fn listing_src(&self) -> &ListingSource;
fn evacuate<'a>(loader: Loader<'a, Self>) -> Result<Self::Evacuable, SessionError>;
}
#[derive(Debug)]
pub(super) struct BootstrappingTermStream<'a> {
listing_src: ListingSource,
parser: Parser<'a, Stream>,
}
impl<'a> BootstrappingTermStream<'a> {
#[inline]
pub(super) fn from_prolog_stream(
stream: &'a mut PrologStream,
atom_tbl: TabledData<Atom>,
flags: MachineFlags,
listing_src: ListingSource,
) -> Self {
let parser = Parser::new(stream, atom_tbl, flags);
Self {
parser,
listing_src,
}
}
}
impl<'a> TermStream for BootstrappingTermStream<'a> {
type Evacuable = CompilationTarget;
#[inline]
fn next(&mut self, op_dir: &CompositeOpDir) -> Result<Term, CompilationError> {
self.parser.reset();
self.parser
.read_term(op_dir)
.map_err(CompilationError::from)
}
#[inline]
fn eof(&mut self) -> Result<bool, CompilationError> {
self.parser.devour_whitespace()?; // eliminate dangling comments before checking for EOF.
Ok(self.parser.eof()?)
}
#[inline]
fn listing_src(&self) -> &ListingSource {
&self.listing_src
}
fn evacuate(mut loader: Loader<Self>) -> Result<Self::Evacuable, SessionError> {
if !loader.predicates.is_empty() {
loader.compile_and_submit()?;
}
loader
.load_state
.retraction_info
.reset(loader.load_state.wam.code_repo.code.len());
loader.load_state.remove_module_op_exports();
Ok(loader.load_state.compilation_target.take())
}
}
pub struct LiveTermStream {
pub(super) term_queue: VecDeque<Term>,
pub(super) listing_src: ListingSource,
}
impl LiveTermStream {
#[inline]
pub(super) fn new(listing_src: ListingSource) -> Self {
Self {
term_queue: VecDeque::new(),
listing_src,
}
}
}
pub struct LoadStatePayload {
pub(super) term_stream: LiveTermStream,
pub(super) compilation_target: CompilationTarget,
pub(super) retraction_info: RetractionInfo,
pub(super) module_op_exports: Vec<(OpDecl, Option<(usize, Specifier)>)>,
pub(super) non_counted_bt_preds: IndexSet<PredicateKey>,
pub(super) predicates: PredicateQueue,
pub(super) clause_clauses: Vec<(Term, Term)>,
}
impl fmt::Debug for LoadStatePayload {
fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
write!(fmt, "LoadStatePayload")
}
}
impl LoadStatePayload {
pub(super) fn new(wam: &Machine) -> Self {
Self {
term_stream: LiveTermStream::new(ListingSource::User),
compilation_target: CompilationTarget::default(),
retraction_info: RetractionInfo::new(wam.code_repo.code.len()),
module_op_exports: vec![],
non_counted_bt_preds: IndexSet::new(),
predicates: predicate_queue![],
clause_clauses: vec![],
}
}
}
impl TermStream for LiveTermStream {
type Evacuable = LoadStatePayload;
#[inline]
fn next(&mut self, _: &CompositeOpDir) -> Result<Term, CompilationError> {
Ok(self.term_queue.pop_front().unwrap())
}
#[inline]
fn eof(&mut self) -> Result<bool, CompilationError> {
return Ok(self.term_queue.is_empty());
}
#[inline]
fn listing_src(&self) -> &ListingSource {
&self.listing_src
}
#[inline]
fn evacuate(loader: Loader<Self>) -> Result<LoadStatePayload, SessionError> {
Ok(loader.to_load_state_payload())
}
}