1 files changed, 42 insertions, 0 deletions
diff --git a/macros/src/syntax/parse/monotonic.rs b/macros/src/syntax/parse/monotonic.rs
new file mode 100644
index 00000000..05832339
--- /dev/null
+++ b/macros/src/syntax/parse/monotonic.rs
@@ -0,0 +1,42 @@
+use proc_macro2::Span;
+use syn::Attribute;
+use syn::{parse, spanned::Spanned, ItemType, Visibility};
+
+use crate::syntax::parse::util::FilterAttrs;
+use crate::syntax::{
+    ast::{Monotonic, MonotonicArgs},
+    parse::util,
+};
+
+impl MonotonicArgs {
+    pub(crate) fn parse(attr: Attribute) -> parse::Result<Self> {
+        crate::syntax::parse::monotonic_args(attr.path, attr.tokens)
+    }
+}
+
+impl Monotonic {
+    pub(crate) fn parse(args: MonotonicArgs, item: &ItemType, span: Span) -> parse::Result<Self> {
+        if item.vis != Visibility::Inherited {
+            return Err(parse::Error::new(
+                span,
+                "this field must have inherited / private visibility",
+            ));
+        }
+
+        let FilterAttrs { cfgs, attrs, .. } = util::filter_attributes(item.attrs.clone());
+
+        if !attrs.is_empty() {
+            return Err(parse::Error::new(
+                attrs[0].path.span(),
+                "Monotonic does not support attributes other than `#[cfg]`",
+            ));
+        }
+
+        Ok(Monotonic {
+            cfgs,
+            ident: item.ident.clone(),
+            ty: item.ty.clone(),
+            args,
+        })
+    }
+}