28 lines
656 B
Plaintext
28 lines
656 B
Plaintext
use crate::{Tree, Literal};
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grammar<'s>();
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pub(crate) Tree: Tree = {
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"(" <Tree+> ")" => Tree::Branch(<>),
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"(" "define" <Sym> <BTree> ")" => Tree::Define(<>),
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"(" "if" <Tree> <Tree> <Tree> ")" => Tree::If(Box::new([<>])),
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Literal => Tree::Leaf(<>),
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}
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BTree = { Box<Tree> }
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Literal: Literal = {
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Sym => Literal::Sym(<>),
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Num => Literal::Num(<>),
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Bool => Literal::Bool(<>),
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}
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Box<T>: Box<T> = { T => Box::new(<>) }
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Sym: String = { r"[A-Za-z!$%&*+\-./:<=>?@^_~][A-Za-z!$%&*+\-./:<=>?@^_~0-9]*" => <>.to_owned() }
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Num: f64 = { r"[0-9]+(\.[0-9]+)?" => <>.parse().unwrap() }
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Bool: bool = {
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"#t" => true,
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"#f" => false,
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} |