1 files changed, 51 insertions, 0 deletions
diff --git a/rtic-macros/src/syntax/parse/init.rs b/rtic-macros/src/syntax/parse/init.rs
new file mode 100644
index 00000000..0aea20bd
--- /dev/null
+++ b/rtic-macros/src/syntax/parse/init.rs
@@ -0,0 +1,51 @@
+use proc_macro2::TokenStream as TokenStream2;
+
+use syn::{parse, ItemFn};
+
+use crate::syntax::{
+    ast::{Init, InitArgs},
+    parse::{self as syntax_parse, util},
+};
+
+impl InitArgs {
+    pub(crate) fn parse(tokens: TokenStream2) -> parse::Result<Self> {
+        syntax_parse::init_args(tokens)
+    }
+}
+
+impl Init {
+    pub(crate) fn parse(args: InitArgs, item: ItemFn) -> parse::Result<Self> {
+        let valid_signature = util::check_fn_signature(&item, false) && item.sig.inputs.len() == 1;
+
+        let span = item.sig.ident.span();
+
+        let name = item.sig.ident.to_string();
+
+        if valid_signature {
+            if let Ok((user_shared_struct, user_local_struct)) =
+                util::type_is_init_return(&item.sig.output)
+            {
+                if let Some((context, Ok(rest))) = util::parse_inputs(item.sig.inputs, &name) {
+                    if rest.is_empty() {
+                        return Ok(Init {
+                            args,
+                            attrs: item.attrs,
+                            context,
+                            name: item.sig.ident,
+                            stmts: item.block.stmts,
+                            user_shared_struct,
+                            user_local_struct,
+                        });
+                    }
+                }
+            }
+        }
+
+        Err(parse::Error::new(
+            span,
+            format!(
+                "the `#[init]` function must have signature `fn({name}::Context) -> (Shared resources struct, Local resources struct)`"
+            ),
+        ))
+    }
+}