tylisp/

macros.rs

/// sexprs, the building blocks of everything Lisp
///
/// This crate uses an unusal sexpression syntax in order to be Rust-compatible:
/// * Curly braces `{}` are used for delimiters instead of parentheses
/// * Terms are separated by commas instead of whitespace
/// * The quote character is `@`
/// * Atoms are arbitrary Rust types
/// * The final comma can be replaced by `;` to suppress the automatic `HNil`
#[macro_export]
macro_rules! sexpr {
    // The empty s-expression is `HNil`
    { $(;)? } => {
        $crate::HNil
    };


    // A leading semicolon parses a single term
    { ; { $($head:tt)* } } => {
        $crate::sexpr!{ $($head)* }
    };

    { ; @ {$($head:tt)*} $(= $val:expr)? } => {
        $crate::Quote< $crate::sexpr!{ $($head)* } >
    };

    { ; @ $head:ty $(= $val:expr)? } => {
        $crate::Quote< $head >
    };

    { ; $head:ty } => { $head };


    // Two terms separated by a semicolon are a pair
    { { $($head:tt)* } ; $($tail:tt)+ } => {
        $crate::HCons< $crate::sexpr!{$($head)*},
                       $crate::sexpr!{;$($tail)*} >
    };

    { @ {$($head:tt)*} $(= $val:expr)? ; $($tail:tt)+ } => {
        $crate::HCons< $crate::Quote< $crate::sexpr!{$($head)*}>,
                       $crate::sexpr!{;$($tail)*} >
    };

    { @ $head:ty $(= $val:expr)?; $($tail:tt)+ } => {
        $crate::HCons< $crate::Quote< $head >,
                       $crate::sexpr!{;$($tail)*} >
    };

    { $head:ty ; $($tail:tt)+ } => {
        $crate::HCons< $head,
                       $crate::sexpr!{;$($tail)*} >
    };

    
    // A term followed by a comma is the head of a list
    { { $($head:tt)* } $(, $($tail:tt)*)? } => {
        $crate::HCons< $crate::sexpr!{$($head)*},
                       $crate::sexpr!{$($($tail)*)?} >
    };

    { @ {$($head:tt)*} $(= $val:expr)? $(, $($tail:tt)*)? } => {
        $crate::HCons< $crate::Quote< $crate::sexpr!{ $($head)* } >,
                       $crate::sexpr!{$($($tail)*)?} >
    };

    { @ $head:ty $(= $val:expr)? $(, $($tail:tt)*)? } => {
        $crate::HCons< $crate::Quote< $head >,
                       $crate::sexpr!{$($($tail)*)?} >
    };

    { $head:ty $(, $($tail:tt)*)? } => {
        $crate::HCons< $head,
                       $crate::sexpr!{$($($tail)*)?} >
    };
}

#[macro_export]
macro_rules! sexpr_quoted_types {
    // The empty s-expression is `HNil`
    { $(;)? } => {
        $crate::HNil
    };


    // A leading semicolon parses a single term
    { ; { $($head:tt)* } } => { () };
    { ; @ {$($head:tt)*}=$val:expr } => {
        $crate::sexpr!{$($head:tt)*} = $val
    };
    { ; @ {$($head:tt)*} } => { () };
    { ; @ $head:ty=$val:expr } => {
        $head = $val
    };
    { ; @ $head:ty } => { () };
    { ; $head:ty } => { () };


    // Two terms separated by a semicolon are a pair
    { { $($head:tt)* } ; $($tail:tt)+ } => {
        $crate::HCons < $crate::sexpr_quoted_types!{$($head)*},
                        $crate::sexpr_quoted_types!{;$($tail)*} >
    };

    { @ {$($head:tt)*} = $val:expr ; $($tail:tt)+ } => {
        $crate::HCons < $crate::sexpr!{$($head:tt)*},
                        $crate::sexpr_quoted_types!{;$($tail)*} >
    };
    { @ {$($head:tt)*} ; $($tail:tt)+ } => {
        $crate::HCons < (),
                        $crate::sexpr_quoted_types!{;$($tail)*} >
    };

    { @ $head:ty = $val:expr; $($tail:tt)+ } => {
        $crate::HCons< $head,
                       $crate::sexpr_quoted_types!{;$($tail)*} >
    };
    { @ $head:ty; $($tail:tt)+ } => {
        $crate::HCons< (),
                       $crate::sexpr_quoted_types!{;$($tail)*} >
    };

    { $head:ty ; $($tail:tt)+ } => {
        $crate::HCons< (),
                       $crate::sexpr_quoted_types!{;$($tail)*} >
    };

    
    // A term followed by a comma is the head of a list
    { { $($head:tt)* } $(, $($tail:tt)*)? } => {
        $crate::HCons< $crate::sexpr_quoted_types!{$($head)*},
                       $crate::sexpr_quoted_types!{$($($tail)*)?} >
    };

    { @ {$($head:tt)*} = $val:expr $(, $($tail:tt)*)? } => {
        $crate::HCons< $crate::sexpr!{$($head:tt)*},
                       $crate::sexpr_quoted_types!{$($($tail)*)?} >
    };

    { @ {$($head:tt)*} $(, $($tail:tt)*)? } => {
        $crate::HCons< (),
                       $crate::sexpr_quoted_types!{$($($tail)*)?} >
    };

    { @ $head:ty = $val:expr $(, $($tail:tt)*)? } => {
        $crate::HCons< $head,
                       $crate::sexpr_quoted_types!{$($($tail)*)?} >
    };

    { @ $head:ty $(, $($tail:tt)*)? } => {
        $crate::HCons< (),
                       $crate::sexpr_quoted_types!{$($($tail)*)?} >
    };

    { $head:ty $(, $($tail:tt)*)? } => {
        $crate::HCons< (),
                       $crate::sexpr_quoted_types!{$($($tail)*)?} >
    };
}


/// Internal macro to extract quoted expressions from an `sexpr`
#[macro_export]
macro_rules! sexpr_quoted_vals {
    // The empty s-expression is `HNil`
    { $(;)? } => {
        $crate::HNil
    };


    // A leading semicolon parses a single term
    { ; { $($head:tt)* } } => { () };
    { ; @ {$($head:tt)*}=$val:expr } => {
        {let _x:$crate::sexpr!{$($head:tt)*} = $val; _x}
    };
    { ; @ {$($head:tt)*} } => { () };
    { ; @ $head:ty=$val:expr } => {
        {let _x:$head = $val; _x}
    };
    { ; @ $head:ty } => { () };
    { ; $head:ty } => { () };


    // Two terms separated by a semicolon are a pair
    { { $($head:tt)* } ; $($tail:tt)+ } => {
        $crate::HCons { head : $crate::sexpr_quoted_vals!{$($head)*},
                        tail : $crate::sexpr_quoted_vals!{;$($tail)*} }
    };

    { @ {$($head:tt)*} = $val:expr ; $($tail:tt)+ } => {
        $crate::HCons { head : {let _x:$crate::sexpr!{$($head:tt)*} = $val; _x},
                        tail : $crate::sexpr_quoted_vals!{;$($tail)*} }
    };
    { @ {$($head:tt)*} ; $($tail:tt)+ } => {
        $crate::HCons { head: (),
                        tail: $crate::sexpr_quoted_vals!{;$($tail)*} }
    };

    { @ $head:ty = $val:expr; $($tail:tt)+ } => {
        $crate::HCons{ head: {let _x:$head = $val; _x},
                       tail: $crate::sexpr_quoted_vals!{;$($tail)*} }
    };
    { @ $head:ty; $($tail:tt)+ } => {
        $crate::HCons{ head: (),
                       tail: $crate::sexpr_quoted_vals!{;$($tail)*} }
    };

    { $head:ty ; $($tail:tt)+ } => {
        $crate::HCons{ head: (),
                       tail: $crate::sexpr_quoted_vals!{;$($tail)*} }
    };

    
    // A term followed by a comma is the head of a list
    { { $($head:tt)* } $(, $($tail:tt)*)? } => {
        $crate::HCons{ head: $crate::sexpr_quoted_vals!{$($head)*},
                       tail: $crate::sexpr_quoted_vals!{$($($tail)*)?} }
    };

    { @ {$($head:tt)*} = $val:expr $(, $($tail:tt)*)? } => {
        $crate::HCons{ head: {let _x:$crate::sexpr!{$($head:tt)*} = $val; _x},
                       tail: $crate::sexpr_quoted_vals!{$($($tail)*)?} }
    };

    { @ {$($head:tt)*} $(, $($tail:tt)*)? } => {
        $crate::HCons{ head: (),
                       tail: $crate::sexpr_quoted_vals!{$($($tail)*)?} }
    };

    { @ $head:ty = $val:expr $(, $($tail:tt)*)? } => {
        $crate::HCons{ head: {let _x:$head = $val; _x},
                       tail: $crate::sexpr_quoted_vals!{$($($tail)*)?} }
    };

    { @ $head:ty $(, $($tail:tt)*)? } => {
        $crate::HCons{ head: (),
                       tail: $crate::sexpr_quoted_vals!{$($($tail)*)?} }
    };

    { $head:ty $(, $($tail:tt)*)? } => {
        $crate::HCons{ head: (),
                       tail: $crate::sexpr_quoted_vals!{$($($tail)*)?} }
    };
}

/// Build an sexpr type from expressions.
#[macro_export]
macro_rules! sexpr_val {
    // The empty s-expression is `HNil`
    { $(;)? } => {
        $crate::HNil
    };

    // A leading semicolon parses a single term
    { ; @{ $($head:tt)* } } => { $crate::sexpr_val!{$($head)*} };
    { ; $head:expr } => { $head };
   
    { @{ $($head:tt)* } ; $($tail:tt)* } => {
        $crate::HCons{ head: $crate::sexpr_val!{$($head)*},
                       tail: $crate::sexpr_val!{;$($tail)*} }
    };
    { $head:expr ; $($tail:tt)* } => {
        $crate::HCons{ head: $head,
                       tail: $crate::sexpr_val!{;$($tail)*} }
    };

    { @{ $($head:tt)* } $(, $($tail:tt)*)? } => {
        $crate::HCons{ head: $crate::sexpr_val!{$($head)*},
                       tail: $crate::sexpr_val!{$($($tail)*)?} }
    };
    { $head:expr $(, $($tail:tt)*)? } => {
        $crate::HCons{ head: $head,
                       tail: $crate::sexpr_val!{$($($tail)*)?} }
    };
}


/// Build an sexpr type from expressions.
#[macro_export]
macro_rules! sexpr_pat_ty {
    // The empty s-expression is `HNil`
    { $(;)? } => {
        $crate::HNil
    };

    // A leading semicolon parses a single term
    { ; { $($head:tt)* } } => { $crate::sexpr_pat_ty!{$($head)*} };
    { ; $head:tt : $ty:ty } => { $ty };
   
    { { $($head:tt)* } ; $($tail:tt)* } => {
        $crate::HCons< $crate::sexpr_pat_ty!{$($head)*},
                       $crate::sexpr_pat_ty!{;$($tail)*} >
    };
    { $head:tt : $ty:ty; $($tail:tt)* } => {
        $crate::HCons< $ty,
                       $crate::sexpr_pat_ty!{;$($tail)*} >
    };

    { { $($head:tt)* } $(, $($tail:tt)*)? } => {
        $crate::HCons< $crate::sexpr_pat_ty!{$($head)*},
                       $crate::sexpr_pat_ty!{$($($tail)*)?} >
    };
    { $head:tt : $ty:ty $(, $($tail:tt)*)? } => {
        $crate::HCons< $ty,
                       $crate::sexpr_pat_ty!{$($($tail)*)?} >
    };
}

/// Build an sexpr type from expressions.
#[macro_export]
macro_rules! sexpr_pat {
    // The empty s-expression is `HNil`
    { $(;)? } => {
        $crate::HNil
    };

    // A leading semicolon parses a single term
    { ; { $($head:tt)* } } => { $crate::sexpr_pat!{$($head)*} };
    { ; $head:tt : $ty:ty } => { $head };
   
    { { $($head:tt)* } ; $($tail:tt)* } => {
        $crate::HCons{ head: $crate::sexpr_pat!{$($head)*},
                       tail: $crate::sexpr_pat!{;$($tail)*} }
    };
    { $head:tt : $ty:ty; $($tail:tt)* } => {
        $crate::HCons{ head: $head,
                       tail: $crate::sexpr_pat!{;$($tail)*} }
    };

    { { $($head:tt)* } $(, $($tail:tt)*)? } => {
        $crate::HCons{ head: $crate::sexpr_pat!{$($head)*},
                       tail: $crate::sexpr_pat!{$($($tail)*)?} }
    };
    { $head:tt : $ty:ty $(, $($tail:tt)*)? } => {
        $crate::HCons{ head: $head,
                       tail: $crate::sexpr_pat!{$($($tail)*)?} }
    };
}

/// Shorthand for resolving a lisp expression into its resultant type
#[macro_export]
macro_rules! eval { ($($expr:tt)*) => { <$crate::sexpr!{$($expr)*} as $crate::engine::Eval>::Result } }

#[macro_export]
macro_rules! partial { ($($expr:tt)*) => { $crate::ops::PartialImpl<$crate::sexpr!{$($expr)*}> }}

#[macro_export]
macro_rules! calc { ($($expr:tt)*) => {
    $crate::engine::calc::<$crate::sexpr!{$($expr)*}, $crate::sexpr_quoted_types!{$($expr)*}>(
        $crate::sexpr_quoted_vals!{$($expr)*}
    )
}}

#[macro_export]
macro_rules! calc_ty { ($($expr:tt)*) => {
    <$crate::sexpr!{$($expr)*} as $crate::engine::Calc<$crate::sexpr_quoted_types!{$($expr)*}>>::Result
}}

#[macro_export]
macro_rules! calc_bound { ($($expr:tt)*) => {
    $crate::engine::Calc<$crate::sexpr_quoted_types!{$($expr)*}>
}}

/// Define types as lisp literals, which evaluate to themselves
#[macro_export]
macro_rules! literal {
    { $(
        $({$($gen:tt)*})? $ty:ty
    );+ } => { $(
        impl$(<$($gen)*>)? $crate::engine::Eval for $ty { type Result = Self; }
        impl<Q,$($($gen)*)?> $crate::engine::Calc<Q> for $ty where Self: ::std::default::Default {
            type Result = Self;
            #[inline(always)]
            fn calc(_:Q)->Self { ::std::default::Default::default() }
        }
        impl$(<$($gen)*>)? $crate::LispId for $ty { type Id = $crate::uuid_new_v4!(| $crate::typenum); }
    )* }
}

#[cfg(feature="const")]
#[macro_export]
macro_rules! literal_with_id {
    { $(
        $({$($gen:tt)*})? $ty:ty : $id:literal
    );+ } => { $(
        impl$(<$($gen)*>)? $crate::engine::Eval for $ty { type Result = Self; }
        impl<Q,$($($gen)*)?> $crate::engine::Calc<Q> for $ty where Self: ::std::default::Default {
            type Result = Self;
            #[inline(always)]
            fn calc(_:Q)->Self { ::std::default::Default::default() }
        }
        impl$(<$($gen)*>)? $crate::LispId for $ty {
            type Id = $crate::ConstId<$id>;
        }
    )* }
}

#[macro_export]
macro_rules! non_calc_literal {
    { $(
        $({$($gen:tt)*})? $ty:ty
    );+ } => { $(
        impl$(<$($gen)+>)? $crate::engine::Eval for $ty { type Result = Self; }
        impl$(<$($gen)+>)? $crate::LispId for $ty { type Id = $crate::uuid_new_v4!(| $crate::typenum); }
    )* }
}

/// Setup a new function, and some match arms for implementation
///
/// This is really a cross between a macro and a traditional Lisp
/// function.  It takes evaluated arguments as input (which means
/// bounds can easily be placed on the result), but builds syntax
/// that, when evaluated, produces the correct result.
///
/// In more complicated situations, it may be beneficial (or necessary)
/// to write some or all of the trait implementations directly.
#[macro_export]
macro_rules! defun {
    {$id:ty { $($body:tt)* }} => {$crate::defun!{@self () $id { $($body)* }}};
    {@$self: tt ($($id_gen:tt)*) $id:ty { $(
        ($($generics:tt)*) $(calc where ($($calcbound:tt)*))? { $($args:tt)* } $({$($preamble:stmt;)*})? => { $($out:tt)* };
    )* }} => {
        $crate::defun_nocalc!{($($id_gen)*) $id {$(
            ( $($generics)* ) { $($args)* } => { $($out)* };
        )*}}
        $(
            impl<$($generics)*> $crate::engine::FunCalc< $crate::sexpr_pat_ty!{$($args)*} > for $id
            where
                //$id: $crate::engine::FunCall< $crate::sexpr_pat_ty!{$($args)*} >,
                $crate::sexpr!{$($out)*}: $crate::engine::Calc< $crate::sexpr_quoted_types!{$($out)*} >,
                $($($calcbound)*)?
            {
                type Result = <$crate::sexpr!{ $($out)* } as $crate::engine::Calc< $crate::sexpr_quoted_types!{$($out)*} >>::Result;
                #[inline(always)]
                fn calc($self, args: $crate::sexpr_pat_ty!{$($args)*})
                -> Self::Result {
                    #[allow(redundant_semicolons)]
                    let syntax: $crate::sexpr_quoted_types!{$($out)*} = {
                        let $crate::sexpr_pat!{$($args)*}: $crate::sexpr_pat_ty!{$($args)*} = args;
                        $($($preamble;)*)?
                        $crate::sexpr_quoted_vals!{$($out)*}
                    };
                    <$crate::sexpr!{$($out)*} as $crate::engine::Calc< $crate::sexpr_quoted_types!{$($out)*} >>::calc(syntax)
                }
            }
        )*
    }
}

/// A trait that all values implement.
///
/// Used as a base case in macro expansions that take optional trait bound arguments.
pub trait Everything {}
impl<T:?Sized> Everything for T {} 

#[macro_export]
macro_rules! defun_rust {
    ( ($($header:tt)+) -> {$($expr:tt)*} $((as $($res_bound:tt)+))? $(where $($bound:tt)+)? ) => {
        $($header)+ -> <$crate::sexpr!{ $($expr)* } as $crate::engine::Calc< $crate::sexpr_quoted_types!{$($expr)*} >>::Result
        where $crate::sexpr!{$($expr)*}: $crate::engine::Calc< $crate::sexpr_quoted_types!{$($expr)*} >,
            <$crate::sexpr!{ $($expr)* } as $crate::engine::Calc< $crate::sexpr_quoted_types!{$($expr)*} >>::Result: $crate::macros::Everything + $($($res_bound)+,)?
            $( $($bound)+)?
        {
            let syntax: $crate::sexpr_quoted_types!{$($expr)*} = $crate::sexpr_quoted_vals!{$($expr)*};
            <$crate::sexpr!{$($expr)*} as $crate::engine::Calc< $crate::sexpr_quoted_types!{$($expr)*} >>::calc(syntax)
        }
    }
}

#[macro_export]
macro_rules! defun_nocalc {
    {($($id_gen:tt)*) $id:ty { $(
        ($($generics:tt)*) { $($args:tt)* } $(where ($($bound:tt)+))? => { $($out:tt)* };
    )* }} => {
        $crate::literal!{{$($id_gen)*} $id}
        impl<$($id_gen)*> $crate::engine::Call for $id { type Conv=$crate::engine::cc::Func; }
        $(
            impl<$($generics)*> $crate::engine::FunCall< $crate::sexpr_pat_ty!{$($args)*} > for $id
            where $crate::sexpr!{$($out)*}: $crate::engine::Eval $(,$($bound)+)? {
                type Result = $crate::eval!{ $($out)* };
            }
        )*
    }
}

/// Setup a new macro function, and some match arms for implementation
///
/// The only difference between this and `defun_nocalc!` is that the arguments
/// are provided un-evaluated, which means you're matching on syntax
/// instead of results.  It therefore provides the opportunity to
/// short-circuit evaluation of some arguments.
#[macro_export]
macro_rules! defmacro {
    {$id:ty { $(
        ($($generics:tt)*) { $($args:tt)* } => { $($out:tt)* };
    )* }} => {
        $crate::literal!{$id}
        impl $crate::engine::Call for $id { type Conv=$crate::engine::cc::Syntax; }
        $(
            impl<$($generics)*> $crate::engine::SynCall< sexpr!{$($args)*} > for $id
            where $crate::sexpr!{$($out)*}: $crate::engine::Eval {
                type Result = $crate::eval!{ $($out)* };
            }
        )*
    }
}

#[cfg(test)]
macro_rules! assert_type_eq {
    ($a:ty, $b:ty) => { let _: ::core::marker::PhantomData<$a>=
        <::core::marker::PhantomData<$b> as ::core::default::Default>::default();
    }
}