organic/src/iter/macros.rs

/// Write the implementation of From<> to convert a borrow of the type to an AstNode
macro_rules! to_ast_node {
    ($inp:ty, $enum:expr) => {
        impl<'r, 's> From<$inp> for AstNode<'r, 's> {
            fn from(value: $inp) -> Self {
                $enum(value)
            }
        }
    };
}

pub(crate) use to_ast_node;

/// Create iterators for ast nodes where it only has to iterate over children
macro_rules! children_iter {
    ($astnodetype:ty, $itertype:ident, $innertype:ty) => {
        pub struct $itertype<'r, 's> {
            next: $innertype,
        }

        impl<'r, 's> Iterator for $itertype<'r, 's> {
            type Item = AstNode<'r, 's>;

            fn next(&mut self) -> Option<Self::Item> {
                self.next.next().map(Into::<AstNode>::into)
            }
        }

        impl<'r, 's> IntoIterator for &'r $astnodetype {
            type Item = AstNode<'r, 's>;

            type IntoIter = $itertype<'r, 's>;

            fn into_iter(self) -> Self::IntoIter {
                $itertype {
                    next: self.children.iter(),
                }
            }
        }
    };
}

pub(crate) use children_iter;

/// Create iterators for ast nodes that do not contain any ast node children.
macro_rules! empty_iter {
    ($astnodetype:ty, $itertype:ident) => {
        pub struct $itertype<'r, 's> {
            phantom: PhantomData<&'r $astnodetype>,
        }

        impl<'r, 's> Iterator for $itertype<'r, 's> {
            type Item = AstNode<'r, 's>;

            fn next(&mut self) -> Option<Self::Item> {
                None
            }
        }

        impl<'r, 's> IntoIterator for &'r $astnodetype {
            type Item = AstNode<'r, 's>;

            type IntoIter = $itertype<'r, 's>;

            fn into_iter(self) -> Self::IntoIter {
                $itertype {
                    phantom: PhantomData,
                }
            }
        }
    };
}

pub(crate) use empty_iter;