bendns' repos / rust-fsm
Finite state machines in rust; bendns fork to add types.
Diffstat (limited to 'rust_fsm_dsl/src/parser.rs')
-rw-r--r--rust_fsm_dsl/src/parser.rs34
1 files changed, 34 insertions, 0 deletions
diff --git a/rust_fsm_dsl/src/parser.rs b/rust_fsm_dsl/src/parser.rs
index 0eb3f7c..696fa84 100644
--- a/rust_fsm_dsl/src/parser.rs
+++ b/rust_fsm_dsl/src/parser.rs
@@ -5,6 +5,10 @@ use syn::{
Ident, Token, Visibility,
};
+mod kw {
+ syn::custom_keyword!(derive);
+}
+
/// The output of a state transition
pub struct Output(Option<Ident>);
@@ -101,6 +105,32 @@ impl Parse for TransitionDef {
}
}
+struct Derives {
+ derives: Option<Vec<Ident>>,
+}
+
+impl Parse for Derives {
+ fn parse(input: ParseStream) -> Result<Self> {
+ let lookahead = input.lookahead1();
+ if lookahead.peek(kw::derive) {
+ let kw_derive = input.parse::<kw::derive>()?;
+ let entries_content;
+ parenthesized!(entries_content in input);
+ let entries: Vec<_> = entries_content
+ .parse_terminated::<_, Token![,]>(Ident::parse)?
+ .into_iter()
+ .collect();
+ if entries.is_empty() {
+ return Err(Error::new_spanned(kw_derive, "Derive list cannot be empty"));
+ }
+ return Ok(Derives {
+ derives: Some(entries),
+ });
+ }
+ Ok(Derives { derives: None })
+ }
+}
+
/// Parses the whole state machine definition in the following form (example):
///
/// ```rust,ignore
@@ -121,10 +151,13 @@ pub struct StateMachineDef {
pub name: Ident,
pub initial_state: Ident,
pub transitions: Vec<TransitionDef>,
+ pub derives: Option<Vec<Ident>>,
}
impl Parse for StateMachineDef {
fn parse(input: ParseStream) -> Result<Self> {
+ let Derives { derives } = input.parse()?;
+
let visibility = input.parse()?;
let name = input.parse()?;
@@ -142,6 +175,7 @@ impl Parse for StateMachineDef {
name,
initial_state,
transitions,
+ derives,
})
}
}