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https://github.com/ParkerTenBroeck/automata.git
synced 2026-06-06 21:24:06 -04:00
added explicit accept by for PDAs
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ParkerTenBroeck
parent
d6e4fff782
commit
ba996ee942
4 changed files with 89 additions and 19 deletions
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@ -173,7 +173,7 @@ impl<'a, 'b> FaCompiler<'a, 'b> {
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TL::Item(S("F", _), list) => self.compile_final_states(list, span),
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TL::Item(S(INITIAL_STATE, _), item) => self.compile_initial_state(item, span),
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TL::Item(S(name, dest_s), _) => {
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self.ctx.emit_error(format!("unknown item {name:?}, expected states, alphabet, final states, initial state"), dest_s);
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self.ctx.emit_error(format!("unknown item {name:?}, expected states | alphabet | final states | initial state"), dest_s);
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}
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TL::TransitionFunc(S((S(delta_lower!(pat), _), args), _), list) => {
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@ -60,12 +60,19 @@ dual_struct_serde! { {#[serde_with::serde_as]}
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}
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}
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#[derive(Clone, Copy)]
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enum AcceptBy {
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EmptyStack,
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FinalState,
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}
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pub struct PdaCompiler<'a, 'b> {
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ctx: &'b mut Context<'a>,
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options: Options,
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initial_state: Option<(State<'a>, Span)>,
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initial_stack: Option<(Symbol<'a>, Span)>,
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accept_by: Option<(AcceptBy, Span)>,
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states: HashMap<State<'a>, StateInfo>,
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states_def: Option<Span>,
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@ -92,6 +99,18 @@ impl<'a> Pda<'a> {
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}
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}
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macro_rules! accept_empty {
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($ident: ident) => {
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$crate::maker!($ident: "N","n","null","empty","E","Z0","z0")
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};
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}
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macro_rules! accept_final {
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($ident: ident) => {
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$crate::maker!($ident: "F","final")
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};
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}
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impl<'a, 'b> PdaCompiler<'a, 'b> {
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pub fn new(ctx: &'b mut Context<'a>, options: Options) -> Self {
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Self {
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@ -100,6 +119,7 @@ impl<'a, 'b> PdaCompiler<'a, 'b> {
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initial_state: Default::default(),
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initial_stack: Default::default(),
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accept_by: Default::default(),
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states: Default::default(),
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states_def: Default::default(),
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symbols: Default::default(),
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@ -140,11 +160,32 @@ impl<'a, 'b> PdaCompiler<'a, 'b> {
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.emit_info_logless(concat!("G can be ", gamma_upper!(str)));
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}
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// if self.final_states_def.is_none() {
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// self.ctx
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// .emit_error_locless("final states never defined")
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// .emit_help_logless("add: F = {...}");
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// }
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if self.accept_by.is_none() {
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self.ctx
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.emit_error_locless("accept by never defined")
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.emit_help_logless("add: accept = N|F")
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.emit_info_logless(concat!(
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"accept by empty stack N can be ",
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accept_empty!(str)
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))
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.emit_info_logless(concat!(
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"accept by final state F can be ",
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accept_final!(str)
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));
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}
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if self.final_states_def.is_none()
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&& matches!(self.accept_by, Some((AcceptBy::FinalState, _)))
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{
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self.ctx
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.emit_error_locless("final states never defined")
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.emit_help_logless("add: F = {...}");
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}else if let (Some((AcceptBy::EmptyStack, empty)), Some(states)) = (self.accept_by, self.final_states_def){
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self.ctx
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.emit_error_locless("final states defined alongside accept by empty stack")
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.emit_help("either remote to accept by empty stack", states)
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.emit_help("or remote to accept by final state", empty);
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}
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let initial_state = match self.initial_state {
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Some(some) => some.0,
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@ -194,13 +235,16 @@ impl<'a, 'b> PdaCompiler<'a, 'b> {
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return None;
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}
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let final_states =
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matches!(self.accept_by, Some((AcceptBy::FinalState, _))).then_some(self.final_states);
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Some(Pda {
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initial_state,
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initial_stack,
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states: self.states,
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symbols: self.symbols,
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alphabet: self.alphabet,
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final_states: Some(self.final_states),
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final_states,
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transitions: self.transitions,
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})
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}
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@ -209,6 +253,7 @@ impl<'a, 'b> PdaCompiler<'a, 'b> {
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use Spanned as S;
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use ast::TopLevel as TL;
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match element {
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TL::Item(S("accept", _), item) => self.compile_accept_by(item, span),
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TL::Item(S("Q", _), list) => self.compile_states(list, span),
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TL::Item(S(gamma_upper!(pat), _), list) => self.compile_symbols(list, span),
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TL::Item(S(sigma_upper!(pat), _), list) => self.compile_alphabet(list, span),
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@ -216,7 +261,7 @@ impl<'a, 'b> PdaCompiler<'a, 'b> {
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TL::Item(S(INITIAL_STATE, _), item) => self.compile_initial_state(item, span),
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TL::Item(S(INITIAL_STACK, _), item) => self.compile_initial_stack(item, span),
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TL::Item(S(name, dest_s), _) => {
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self.ctx.emit_error(format!("unknown item {name:?}, expected states, stack symbols, alphabet, final states, initial state, initial stack"), dest_s);
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self.ctx.emit_error(format!("unknown item {name:?}, expected states | stack symbols | alphabet | accept by | final states | initial state | initial stack"), dest_s);
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}
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TL::TransitionFunc(S((S(delta_lower!(pat), _), args), _), list) => {
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@ -239,6 +284,28 @@ impl<'a, 'b> PdaCompiler<'a, 'b> {
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}
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}
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fn compile_accept_by(&mut self, item: Spanned<ast::Item<'a>>, top_level: Span) {
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if let Some((_, previous)) = self.accept_by {
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self.ctx
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.emit_error("accept by already set", top_level)
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.emit_info("previously defined here", previous);
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}
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let Some(by) = item.expect_ident(self.ctx) else {
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return;
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};
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let by = match by {
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accept_empty!(pat) => AcceptBy::EmptyStack,
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accept_final!(pat) => AcceptBy::FinalState,
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_ => {
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self.ctx.emit_error("invalid accept by", item.1);
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return;
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}
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};
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self.accept_by = Some((by, top_level));
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}
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fn compile_states(&mut self, list: Spanned<ast::Item<'a>>, top_level: Span) {
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if let Some(previous) = self.states_def {
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self.ctx
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@ -190,7 +190,7 @@ impl<'a, 'b> TmCompiler<'a, 'b> {
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TL::Item(S(INITIAL_STATE, _), item) => self.compile_initial_state(item, span),
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TL::Item(S(BLANK_SYMBOL, _), item) => self.compile_blank_symbol(item, span),
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TL::Item(S(name, dest_s), _) => {
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self.ctx.emit_error(format!("unknown item {name:?}, expected states, symbols, final states, initial state, blank symbol"), dest_s);
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self.ctx.emit_error(format!("unknown item {name:?}, expected states | symbols | final states | initial state | blank symbol"), dest_s);
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}
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TL::TransitionFunc(S((S(delta_lower!(pat), _), args), _), list) => {
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@ -27,11 +27,11 @@ export const examples: readonly Example[] = [
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"DFA",
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`// strings over a,b which start and end with different letters
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type = DFA // type of machine DFA, NFA, DPDA, NPDA, DTM, NTM
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Q = {q0, qa, qa', qb, qb'} // set of states
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E = {a, b} // alphabet
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F = {qa', qb'} // set of final states
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q0 = q0 // initial state
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type = DFA // type of machine DFA, NFA, DPDA, NPDA, DTM, NTM
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Q = {q0, qa, qa', qb, qb'} // set of states
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E = {a, b} // alphabet
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F = {qa', qb'} // set of final states
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q0 = q0 // initial state
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// transition function (state, letter) -> state
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d(q0, a) = qa
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@ -81,11 +81,12 @@ d(q4, 3) = q2`,
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new Example(
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"DPDA",
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"unequal",
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`type=DPDA
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Q = {q0, qas, qeq, qmb, qlb} // states
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E = {a, b} // alphabet
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T = {z0, A} // stack
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F = {qmb, qlb} // final states
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`type = DPDA
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Q = {q0, qas, qeq, qmb, qlb} // states
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E = {a, b} // alphabet
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T = {z0, A} // stack
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F = {qmb, qlb} // final states
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accept = F // accept by final state
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q0 = q0
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z0 = z0
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@ -112,6 +113,7 @@ d(qmb, b, z0) = (qmb, z0)`,
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Q = {q0, q1} // states
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E = {a, b} // alphabet
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T = {z0, A, B} // stack
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accept = E // accept by empty stack
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q0 = q0
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z0 = z0
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@ -142,6 +144,7 @@ d(q1, b, B) = { (q1, epsilon) }`,
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Q = {q0, q1} // states
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E = {a, b} // alphabet
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T = {z0, A, B} // stack
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accept = E // accept by empty stack
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q0 = q0
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z0 = z0
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