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use crate::ast::{self, Expr};
use crate::token::*;
pub use rules::*;
peg::parser! {
pub grammar rules<'a>() for TokenStream<'a> {
use ast::OpBinary::*;
use ast::OpUnary::*;
pub rule recipe() -> ast::Recipe<'a>
= recipe:recipe_stmt()* { recipe }
pub rule recipe_stmt() -> ast::RecipeStmt<'a>
= [Token::Keyword(Keyword::Fetch)] name:ident() p('{') body:body() p('}') {
ast::RecipeStmt::Fetch { name, body: ast::Body(Vec::new()) }
}
/ [Token::Keyword(Keyword::Task)] name:ident() p('(') params:func_params() p(')')
p('{') body:body() p('}') {
ast::RecipeStmt::Task { name, params, body }
}
/ stmt:body_stmt() p(';') {
ast::RecipeStmt::BodyStmt(stmt)
}
pub rule body() -> ast::Body<'a>
= body:body_stmt() ++ p(';') { ast::Body(body) }
pub rule body_stmt() -> ast::BodyStmt<'a>
= dest:typed_expr() op:assign_op() expr:expr() {
ast::BodyStmt::assign(dest, op, false, expr)
}
/ dest:typed_expr() p2('=', '+') expr:expr() {
ast::BodyStmt::assign(dest, Some(Add), true, expr)
}
/ expr:expr() {
ast::BodyStmt::Expr { expr: Box::new(expr) }
}
/ { ast::BodyStmt::Empty }
rule assign_op() -> Option<ast::OpBinary>
= p('=') { None }
/ p2('+', '=') { Some(Add) }
/ p2('-', '=') { Some(Sub) }
/ p2('*', '=') { Some(Mul) }
/ p2('/', '=') { Some(Div) }
/ p2('%', '=') { Some(Rem) }
rule typed_expr() -> ast::TypedExpr<'a>
= expr:expr() typ:tagged(<p(':')>, <expr()>)? { ast::TypedExpr { expr, typ } }
pub rule expr() -> Expr<'a> = precedence! {
left:(@) p2('|', '|') right:@ { Expr::binary(left, Or, right) }
--
left:(@) p2('&', '&') right:@ { Expr::binary(left, And, right) }
--
left:(@) p2('=', '=') right:@ { Expr::binary(left, Eq, right) }
left:(@) p2('!', '=') right:@ { Expr::binary(left, Ne, right) }
left:(@) p('<') right:@ { Expr::binary(left, Lt, right) }
left:(@) p('>') right:@ { Expr::binary(left, Gt, right) }
left:(@) p2('<', '=') right:@ { Expr::binary(left, Le, right) }
left:(@) p2('>', '=') right:@ { Expr::binary(left, Ge, right) }
--
left:(@) p('+') right:@ { Expr::binary(left, Add, right) }
left:(@) p('-') right:@ { Expr::binary(left, Sub, right) }
--
left:(@) p('*') right:@ { Expr::binary(left, Mul, right) }
left:(@) p('/') right:@ { Expr::binary(left, Div, right) }
left:(@) p('%') right:@ { Expr::binary(left, Rem, right) }
--
p('-') expr:@ { Expr::unary(Neg, expr) }
p('!') expr:@ { Expr::unary(Not, expr) }
--
expr:@ p('(') params:call_params() p(')') {
Expr::apply(expr, params)
}
expr:@ p('[') index:expr() p(']') { Expr::index(expr, index) }
--
expr:@ p('.') method:field() p('(') params:call_params() p(')') {
Expr::method(expr, method, params)
}
expr:@ p('.') field:field() { Expr::field(expr, field) }
--
p('(') e:expr() p(')') { Expr::paren(e) }
e:atom() { e }
}
rule atom() -> Expr<'a>
= lit:literal() { Expr::Literal(lit) }
/ path:path() { Expr::Path(path) }
rule call_params() -> Vec<ast::Expr<'a>>
= args:delimited(<expr()>, <p(',')>) { args }
rule func_params() -> Vec<ast::FuncParam<'a>>
= params:delimited(<func_param()>, <p(',')>) { params }
rule func_param() -> ast::FuncParam<'a>
= name:ident() p(':') typ:expr() { ast::FuncParam { name, typ } }
rule literal() -> ast::Literal<'a>
= [Token::Keyword(Keyword::True)] { ast::Literal::Bool(true) }
/ [Token::Keyword(Keyword::False)] { ast::Literal::Bool(false) }
/ [Token::Number(content)] { ?
ast::Literal::number(content)
}
/ [Token::Str(Str { pieces, kind })] { ?
let pieces = pieces
.iter()
.map(|piece| piece.try_into())
.collect::<Result<_, _>>()?;
Ok(ast::Literal::Str{ pieces, kind: *kind })
}
/ p('(') p(')') { ast::Literal::Unit }
/ p('(') elements:(expr() ** p(',')) p(',')? p(')') {
ast::Literal::Tuple(elements)
}
/ p('[') elements:delimited(<expr()>, <p(',')>) p(']') {
ast::Literal::Array(elements)
}
/ p('{') entries:delimited(<struct_field()>, <p(',')>) p('}') {
ast::Literal::Struct(entries)
}
rule struct_field() -> ast::StructField<'a>
= key:field() p('=') value:expr() {
ast::StructField { key: key.name, value }
}
rule path() -> ast::Path<'a>
= components:ident() ++ p2(':', ':') { ast::Path { components } }
rule field() -> ast::Ident<'a>
= ident()
/ [Token::Number(content)] {
ast::Ident { name: content }
}
rule p_(ch: char)
= [Token::Punct(Punct(c, Spacing::Joint)) if *c == ch] {}
rule p(ch: char) -> ()
= [Token::Punct(Punct(c, _)) if *c == ch] {}
rule p2(ch1: char, ch2: char)
= p_(ch1) p(ch2)
rule ident() -> ast::Ident<'a>
= [Token::Ident(name)] { ast::Ident { name } }
rule delimited<T>(expr: rule<T>, delim: rule<()>) -> Vec<T>
= values:(expr() ++ delim()) delim()? { values }
/ { Vec::new() }
rule tagged<T>(tag: rule<()>, value: rule<T>) -> T
= tag() v:value() { v }
}
}
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