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//! A `Parser` for parsing inputs that are in-memory strings, for no-heap //! constrained applications. use core::iter::TakeWhile; use crate::{ Parser as ParserStruct, ParseIter, ParseIterItem, Combiner, Error, Text as _, parser::premade::{SliceDatumAllocator, PairOperatorBindings}, text::{self, premade::TextDatumList, chunk::premade::{PosStr, StrPos}}, datum::premade::{MutRefDatum, DatumMutRef}, combiner::{OpFn, ApFn}, }; #[doc(no_inline)] pub use crate::parser::premade::DefaultCharClassifier as CharClassifier; /// Chosen so that the referenced parts of an input string are zero-copy, and so /// that `char` and byte positions are tracked (relative to the input `&str`), /// and so that, when chunks are broken around escape characters, a `Datum` list /// is used to logically concatenate them. /// /// This `Text` type is a `TextDatumList` of `PosStr` chunks. pub type Text<'input, 'alloc, Extra = ()> = TextDatumList<'alloc, PosStr<'input>, Extra>; /// Chosen so that the [`Datum`]s in the AST values returned from parsing are /// allocated from a contiguous slice of them, which itself must be /// pre-allocated by you, e.g. as an array on the stack. /// /// This `DatumAllocator` type is a `SliceDatumAllocator` of our `Text` type and /// of the given `Extra` type. /// /// The `Extra` type parameter determines the type used in the [`Datum::Extra`] /// variant of our `Datum` type, and it defaults to `()`. /// /// [`Datum`]: ../../enum.Datum.html /// [`Datum::Extra`]: ../../enum.Datum.html#variant.Extra pub type DatumAllocator<'input, 'alloc, Extra = ()> = SliceDatumAllocator<'alloc, Text<'input, 'alloc, Extra>, Extra>; /// A contiguous slice of our `Datum` type. Used by our [`DatumAllocator`] via /// our [`parser`] constructor. /// /// Useful when defining a borrowed array of `Datum`s to allocate from. /// /// [`DatumAllocator`]: type.DatumAllocator.html /// [`parser`]: fn.parser.html pub type DatumSlice<'input, 'alloc, Extra = ()> = &'alloc mut [DatumType<'input, 'alloc, Extra>]; /// Our `Datum` type. Contains mutable borrows of other `Datum`s of our type, /// wrapped in our [`DatumRef`] type. /// /// [`DatumRef`]: type.DatumRef.html pub type DatumType<'input, 'alloc, Extra = ()> = MutRefDatum<'alloc, Text<'input, 'alloc, Extra>, Extra>; /// Our `Datum` reference type. Wraps mutable borrows of other `Datum`s of our /// type. pub type DatumRef<'input, 'alloc, Extra = ()> = DatumMutRef<'alloc, Text<'input, 'alloc, Extra>, Extra>; /// Chosen so that you may establish bindings using an immutable slice of pairs /// (2-tuples) and with flexible trait objects for the function types. /// /// This `OperatorBindings` type is a `PairOperatorBindings` that binds operator /// sub-forms, as our [`Datum`] type, to [`Combiner`] macro functions/closures, /// as `&dyn` trait objects. /// /// The `Extra` type parameter determines the type used in the [`Datum::Extra`] /// variant of our `Datum` type. It defaults to `()`. /// /// The `CombinerError` type parameter determines the type used in the /// [`Error::FailedCombiner`] variant of the crate's error type which your /// `Combiner` functions may return. It defaults to `()`. /// /// [`Datum`]: ../../enum.Datum.html /// [`Combiner`]: ../../enum.Combiner.html /// [`Datum::Extra`]: ../../enum.Datum.html#variant.Extra /// [`Error::FailedCombiner`]: ../../enum.Error.html#variant.FailedCombiner pub type OperatorBindings<'input, 'alloc, 'funs, 'bind, Extra = (), CombinerError = ()> = PairOperatorBindings< BindingsSlice<'input, 'alloc, 'funs, 'bind, Extra, CombinerError>, DatumAllocator<'input, 'alloc, Extra>, OperativeRef<'input, 'alloc, 'funs, Extra, CombinerError>, ApplicativeRef<'input, 'alloc, 'funs, Extra, CombinerError>, CombinerError >; /// A slice of pairs (2-tuples) that associate operator sub-forms with macro /// functions, to bind them. Used by our [`OperatorBindings`] via our /// [`parser`] constructor. /// /// Useful when defining a borrowed array of bindings. /// /// [`OperatorBindings`]: type.OperatorBindings.html /// [`parser`]: fn.parser.html pub type BindingsSlice<'input, 'alloc, 'funs, 'bind, Extra = (), CombinerError = ()> = &'bind [BindingsPair<'input, 'alloc, 'funs, Extra, CombinerError>]; /// A pair (2-tuple) that associates an operator sub-form with a macro function, /// to bind them. pub type BindingsPair<'input, 'alloc, 'funs, Extra = (), CombinerError = ()> = ( // The operator sub-form DatumType<'input, 'alloc, Extra>, // The macro function bound to the operator Combiner<OperativeRef<'input, 'alloc, 'funs, Extra, CombinerError>, ApplicativeRef<'input, 'alloc, 'funs, Extra, CombinerError>> ); /// Our [`Operative`] reference type. A `&dyn` reference to a function as a /// trait object. /// /// [`Operative`]: ../../combiner/enum.Combiner.html#variant.Operative pub type OperativeRef<'input, 'alloc, 'funs, Extra = (), CombinerError = ()> = &'funs OpFn<DatumAllocator<'input, 'alloc, Extra>, CombinerError>; /// Our [`Applicative`] reference type. A `&dyn` reference to a function as a /// trait object. /// /// [`Applicative`]: ../../combiner/enum.Combiner.html#variant.Applicative pub type ApplicativeRef<'input, 'alloc, 'funs, Extra = (), CombinerError = ()> = &'funs ApFn<DatumAllocator<'input, 'alloc, Extra>, CombinerError>; /// A [`Parser`] for parsing inputs that are in-memory strings, as `&str`s /// wrapped by this module's [`Text`] type, that is suitable for no-heap /// constrained applications that only use the stack, and that uses: the default /// characters as delimiters, slices to allocate the [`Datum`]s in ASTs returned /// from parsing, and slices of pairs (2-tuples) to bind operator sub-forms to /// [`Combiner`] macro functions. /// /// The AST values returned from parsing are zero-copy with regard to the input /// parts they refer to, achieved by borrowing sub-slices of the input slice. /// /// You must decide which types you want to use in the [`Datum::Extra`] variant /// and for any errors returned by your macro/"combiner" functions in the /// [`Error::FailedCombiner`] variant. If unsure, the `()` type is suitable for /// either or both, and this is their default. /// /// [`Parser`]: ../../struct.Parser.html /// [`Text`]: type.Text.html /// [`Datum`]: ../../enum.Datum.html /// [`Combiner`]: ../../enum.Combiner.html /// [`Datum::Extra`]: ../../enum.Datum.html#variant.Extra /// [`Error::FailedCombiner`]: ../../enum.Error.html#variant.FailedCombiner pub type Parser<'input, 'alloc, 'funs, 'bind, Extra = (), CombinerError = ()> = ParserStruct< CharClassifier, DatumAllocator<'input, 'alloc, Extra>, OperatorBindings<'input, 'alloc, 'funs, 'bind, Extra, CombinerError> >; /// The `Result` of parsing a top-level form, and the type of items yielded by /// [`parse_text_with`]. /// /// An `Ok` value contains a [`Datum`] value that is the AST (abstract syntax /// tree) of the parsed top-level form. /// /// An `Err` value contains an [`Error`] value variant that describes the error /// caused by either a syntax error in the input or by one of your [`Combiner`] /// functions returning a value of your chosen `CombinerError` type parameter. /// /// [`parse_text_with`]: fn.parse_text_with.html /// [`Datum`]: ../../enum.Datum.html /// [`Error`]: ../../enum.Error.html /// [`Combiner`]: ../../enum.Combiner.html pub type TopFormResult<'input, 'alloc, 'funs, 'bind, Extra = (), CombinerError = ()> = ParseIterItem< DatumAllocator<'input, 'alloc, Extra>, OperatorBindings<'input, 'alloc, 'funs, 'bind, Extra, CombinerError> >; /// Make a new `Parser` that uses the given `DatumSlice` and `BindingsSlice` /// values for the `DatumAllocator` and `OperatorBindings` and that uses the /// types chosen by this module. /// /// You may call the returned `Parser`'s [`parse`] method and use the /// [`ParseIter`] values however you can. /// /// [`parse`]: ../../struct.Parser.html#method.parse /// [`ParseIter`]: ../../struct.ParseIter.html #[inline] pub fn parser<'input, 'alloc, 'funs, 'bind, Extra, CombinerError>( alloc_from: DatumSlice<'input, 'alloc, Extra>, bind_pairs: BindingsSlice<'input, 'alloc, 'funs, 'bind, Extra, CombinerError> ) -> Parser<'input, 'alloc, 'funs, 'bind, Extra, CombinerError> where Extra: Eq, { ParserStruct { classifier: CharClassifier, allocator: DatumAllocator::new(alloc_from), bindings: OperatorBindings::new(bind_pairs), } } /// Make a new `Parser` that uses the given `DatumSlice` value for the /// `DatumAllocator`, that has no bindings of operators, and that uses the types /// chosen by this module. /// /// See the [`parser`] function, which this simply calls with an empty slice for /// the bindings. /// /// The returned `Parser` will parse all nest forms recursively in the same way /// and produce the [`Datum::Combination`] variant to represent each in the /// returned ASTs. This produces a simplistic kind of S-expression structure /// that is useful when you don't want any special parsing of nested text, /// either because you want to prevent that but still be able to analyze the /// basic structure, or because your application is so simple that it only uses /// the format/language/syntax to this extent. /// /// This uses `()` for the types in the `Datum::Extra` and /// `Error::FailedCombiner` variants, because these variants cannot be produced /// when there are no bindings. /// /// [`parser`]: fn.parser.html /// [`Datum::Combination`]: ../../enum.Datum.html#variant.Combination #[inline] pub fn parser_no_bind<'input, 'alloc, 'funs, 'bind>( alloc_from: DatumSlice<'input, 'alloc>, ) -> Parser<'input, 'alloc, 'funs, 'bind> { parser(alloc_from, &[]) } /// Parse the given `Text`, that contains the input string, using the given /// `Parser`, and return an `Iterator` of the results as `Datum` ASTs for each /// successfully-parsed top-level form and/or an `Error`. /// /// This enables you to give bindings for parsing certain nest forms in your /// custom ways and enables you to [choose][`parser` function] what to use for /// the `Extra` and `CombinerError` type parameters. /// /// If an error is returned by the parser, parsing will be immediately aborted /// and the last item of the returned iterator will be that error. If instead /// you want to continue trying to parse after an error occurred, use the /// [`parser` function] to directly work with a `Parser`. /// /// The reason this function takes borrows of `Text` and `Parser` values is /// because the returned iterator borrows them itself and this is the only way /// the lifetimes can work. /// /// [`Parser`]: type.Parser.html /// [`parser` function]: fn.parser.html pub fn parse_text_with<'t, 'p, 'input, 'alloc, 'funs, 'bind, Extra, CombinerError>( input: &'t Text<'input, 'alloc, Extra>, parser: &'p mut Parser<'input, 'alloc, 'funs, 'bind, Extra, CombinerError>, ) // Note: Couldn't figure out how to make this work: // -> impl Iterator<Item = TopFormResult<'input, 'alloc, 'funs, 'bind, // Extra, CombinerError>> -> ParseTextWith<'t, 'p, 'input, 'alloc, 'funs, 'bind, Extra, CombinerError, impl FnMut(&Result<DatumType<'input, 'alloc, Extra>, Error<StrPos<'input>, CombinerError>>) -> bool> where Extra: Eq, { let input_source_stream = input.iter(); let mut already_errored = false; parser.parse(input_source_stream) .take_while(move |r| if already_errored { false } else { if r.is_err() { already_errored = true; } true }) } type ParseTextWith<'text, 'parser, 'input, 'alloc, 'funs, 'bind, Extra, CombinerError, Predicate> = TakeWhile<ParseIter<'parser, Parser<'input, 'alloc, 'funs, 'bind, Extra, CombinerError>, text::iter::Iter<'text, Text<'input, 'alloc, Extra>>>, Predicate>; #[cfg(test)] mod tests { use super::*; use crate::{Datum, datum::premade::DatumMutRef, parser::DatumAllocator as _, parser::OperatorBindings as _}; #[test] fn datum_allocator() { let a: DatumSlice<'_, '_> = &mut [Datum::Extra(())]; let mut da = DatumAllocator::new(a); let r = da.new_datum(Datum::EmptyNest); assert_eq!(*r.unwrap(), Datum::<Text<'_, '_>, (), DatumMutRef<'_, _, _>>::EmptyNest); } #[test] fn operator_bindings() { let f: OperativeRef<'_, '_, '_> = &(|_, _, _| Ok(None)); let p: BindingsSlice<'_, '_, '_, '_> = &[(Datum::EmptyNest, Combiner::Operative(f))]; let ob = OperatorBindings::new(p); let l = ob.lookup(&Datum::EmptyNest); assert_eq!(l.map(|_| true), Some(true)); assert_eq!(ob.lookup(&Datum::EmptyList).map(|_| true), None); } #[test] fn parser_no_bind() { let a: DatumSlice<'_, '_> = &mut [Datum::Extra(()), Datum::Extra(()), Datum::Extra(()), Datum::Extra(()), Datum::Extra(()), Datum::Extra(())]; let mut p = super::parser_no_bind(a); assert_eq!(super::parse_text_with(&Text::from_str(""), &mut p) .next(), None); let mut ptw = |s| { let t = Text::from_str(s); let mut it = super::parse_text_with(&t, &mut p); let r = it.next().unwrap(); assert!(it.next().is_none()); r }; assert_eq!(ptw("a"), Ok(Datum::Text(Text::from_str("a")))); assert_eq!(ptw("{}"), Ok(Datum::EmptyNest)); let mut dtb = Datum::Text(Text::from_str("b")); let mut dtc = Datum::Text(Text::from_str("c")); let mut del1 = Datum::EmptyList; let mut del2 = Datum::EmptyList; let mut dco = Datum::Combination { operator: DatumMutRef(&mut dtc), operands: DatumMutRef(&mut del1) }; let mut dl = Datum::List { elem: DatumMutRef(&mut dco), next: DatumMutRef(&mut del2), }; assert_eq!(ptw("{b {c}}"), Ok(Datum::Combination { operator: DatumMutRef(&mut dtb), operands: DatumMutRef(&mut dl), })); assert_eq!(ptw("λ} h"), Err(Error::UnbalancedEndChar( StrPos{src: "λ} h", byte_pos: 2, char_pos: 1}))); } #[test] fn parse_text_with() { let a: DatumSlice<'_, '_, i8> = &mut [Datum::Extra(0), Datum::Extra(0)]; let b: BindingsSlice<'_, '_, '_, '_, i8, bool> = &[ (Datum::Text(Text::from_str("op")), Combiner::Operative(&(|_, _, _| Ok(Some(Datum::Extra(1)))))), (Datum::Text(Text::from_str("e")), Combiner::Applicative(&(|_, _, _| Err(Error::FailedCombiner(true))))), ]; let mut p = parser(a, b); assert_eq!(super::parse_text_with(&Text::from_str(""), &mut p) .next(), None); let mut ptw = |s| { let t = Text::from_str(s); let mut it = super::parse_text_with(&t, &mut p); let r = it.next().unwrap(); assert!(it.next().is_none()); r }; assert_eq!(ptw("a"), Ok(Datum::Text(Text::from_str("a")))); assert_eq!(ptw("{}"), Ok(Datum::EmptyNest)); assert_eq!(ptw("{op ignored}"), Ok(Datum::Extra(1))); let mut d1 = Datum::Text(Text::from_str("zz")); let mut d2 = Datum::EmptyList; assert_eq!(ptw("{zz }"), Ok(Datum::Combination { operator: DatumMutRef(&mut d1), operands: DatumMutRef(&mut d2), })); assert_eq!(ptw("{e}aborted"), Err(Error::FailedCombiner(true))); } }