33 lines
659 B
Plaintext
33 lines
659 B
Plaintext
use std::cell::Cell;
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use l1::ast::{Atom, Reg, Term, TopLevel, Var};
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grammar;
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pub TopLevel: TopLevel = {
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"?-" <t:Term> "." => TopLevel::Query(t),
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<t:Term> "." => TopLevel::Fact(t),
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};
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Atom : Atom = {
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r"[a-z][a-z0-9_]*" => <>.trim().to_string(),
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};
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Var : Var = {
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r"[A-Z][a-z0-9_]*" => <>.trim().to_string(),
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};
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BoxedTerm : Box<Term> = {
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<t:Term> => Box::new(t),
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};
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Term : Term = {
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<a:Atom> "(" <ts: (<BoxedTerm> ",")*> <t:BoxedTerm> ")" => {
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let mut ts = ts;
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ts.push(t);
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Term::Clause(Cell::new(0), a, ts)
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},
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<Atom> => Term::Atom(Cell::new(0), <>),
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<Var> => Term::Var(Cell::new(Reg::Norm(0)), <>)
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};
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