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Diffstat (limited to 'users/aspen/achilles/src/parser/mod.rs')
| -rw-r--r-- | users/aspen/achilles/src/parser/mod.rs | 240 |
1 files changed, 240 insertions, 0 deletions
diff --git a/users/aspen/achilles/src/parser/mod.rs b/users/aspen/achilles/src/parser/mod.rs new file mode 100644 index 0000000000..e088cbca10 --- /dev/null +++ b/users/aspen/achilles/src/parser/mod.rs @@ -0,0 +1,240 @@ +use nom::character::complete::{multispace0, multispace1}; +use nom::error::{ErrorKind, ParseError}; +use nom::{alt, char, complete, do_parse, eof, many0, named, separated_list0, tag, terminated}; + +#[macro_use] +pub(crate) mod macros; +mod expr; +mod type_; +mod util; + +use crate::ast::{Arg, Decl, Fun, Ident}; +pub use expr::expr; +use type_::function_type; +pub use type_::type_; + +pub type Error = nom::Err<nom::error::Error<String>>; + +pub(crate) fn is_reserved(s: &str) -> bool { + matches!( + s, + "if" | "then" + | "else" + | "let" + | "in" + | "fn" + | "ty" + | "int" + | "float" + | "bool" + | "true" + | "false" + | "cstring" + ) +} + +pub(crate) fn ident<'a, E>(i: &'a str) -> nom::IResult<&'a str, Ident, E> +where + E: ParseError<&'a str>, +{ + let mut chars = i.chars(); + if let Some(f) = chars.next() { + if f.is_alphabetic() || f == '_' { + let mut idx = 1; + for c in chars { + if !(c.is_alphanumeric() || c == '_') { + break; + } + idx += 1; + } + let id = &i[..idx]; + if is_reserved(id) { + Err(nom::Err::Error(E::from_error_kind(i, ErrorKind::Satisfy))) + } else { + Ok((&i[idx..], Ident::from_str_unchecked(id))) + } + } else { + Err(nom::Err::Error(E::from_error_kind(i, ErrorKind::Satisfy))) + } + } else { + Err(nom::Err::Error(E::from_error_kind(i, ErrorKind::Eof))) + } +} + +named!(ascripted_arg(&str) -> Arg, do_parse!( + complete!(char!('(')) >> + multispace0 >> + ident: ident >> + multispace0 >> + complete!(char!(':')) >> + multispace0 >> + type_: type_ >> + multispace0 >> + complete!(char!(')')) >> + (Arg { + ident, + type_: Some(type_) + }) +)); + +named!(arg(&str) -> Arg, alt!( + ident => { |ident| Arg {ident, type_: None}} | + ascripted_arg +)); + +named!(extern_decl(&str) -> Decl, do_parse!( + complete!(tag!("extern")) + >> multispace1 + >> name: ident + >> multispace0 + >> char!(':') + >> multispace0 + >> type_: function_type + >> multispace0 + >> (Decl::Extern { + name, + type_ + }) +)); + +named!(fun_decl(&str) -> Decl, do_parse!( + complete!(tag!("fn")) + >> multispace1 + >> name: ident + >> multispace1 + >> args: separated_list0!(multispace1, arg) + >> multispace0 + >> char!('=') + >> multispace0 + >> body: expr + >> (Decl::Fun { + name, + body: Fun { + args, + body + } + }) +)); + +named!(ascription_decl(&str) -> Decl, do_parse!( + complete!(tag!("ty")) + >> multispace1 + >> name: ident + >> multispace0 + >> complete!(char!(':')) + >> multispace0 + >> type_: type_ + >> multispace0 + >> (Decl::Ascription { + name, + type_ + }) +)); + +named!(pub decl(&str) -> Decl, alt!( + ascription_decl | + fun_decl | + extern_decl +)); + +named!(pub toplevel(&str) -> Vec<Decl>, do_parse!( + decls: many0!(decl) + >> multispace0 + >> eof!() + >> (decls))); + +#[cfg(test)] +mod tests { + use std::convert::TryInto; + + use crate::ast::{BinaryOperator, Expr, FunctionType, Literal, Type}; + + use super::*; + use expr::tests::ident_expr; + + #[test] + fn fn_decl() { + let res = test_parse!(decl, "fn id x = x"); + assert_eq!( + res, + Decl::Fun { + name: "id".try_into().unwrap(), + body: Fun { + args: vec!["x".try_into().unwrap()], + body: *ident_expr("x"), + } + } + ) + } + + #[test] + fn ascripted_fn_args() { + test_parse!(ascripted_arg, "(x : int)"); + let res = test_parse!(decl, "fn plus1 (x : int) = x + 1"); + assert_eq!( + res, + Decl::Fun { + name: "plus1".try_into().unwrap(), + body: Fun { + args: vec![Arg { + ident: "x".try_into().unwrap(), + type_: Some(Type::Int), + }], + body: Expr::BinaryOp { + lhs: ident_expr("x"), + op: BinaryOperator::Add, + rhs: Box::new(Expr::Literal(Literal::Int(1))), + } + } + } + ); + } + + #[test] + fn multiple_decls() { + let res = test_parse!( + toplevel, + "fn id x = x + fn plus x y = x + y + fn main = plus (id 2) 7" + ); + assert_eq!(res.len(), 3); + let res = test_parse!( + toplevel, + "fn id x = x\nfn plus x y = x + y\nfn main = plus (id 2) 7\n" + ); + assert_eq!(res.len(), 3); + } + + #[test] + fn top_level_ascription() { + let res = test_parse!(toplevel, "ty id : fn a -> a"); + assert_eq!( + res, + vec![Decl::Ascription { + name: "id".try_into().unwrap(), + type_: Type::Function(FunctionType { + args: vec![Type::Var("a".try_into().unwrap())], + ret: Box::new(Type::Var("a".try_into().unwrap())) + }) + }] + ) + } + + #[test] + fn return_unit() { + assert_eq!( + test_parse!(decl, "fn g _ = ()"), + Decl::Fun { + name: "g".try_into().unwrap(), + body: Fun { + args: vec![Arg { + ident: "_".try_into().unwrap(), + type_: None, + }], + body: Expr::Literal(Literal::Unit), + }, + } + ) + } +} |