[Yunq] Codegen example for yunq implementation.

yunq/rust/src/codegen.rs

@@ -0,0 +1,53 @@
+use crate::parser::{Decl, Field, Interface, Message};
+use genco::fmt;
+use genco::fmt::FmtWriter;
+use genco::prelude::quote_fn;
+use genco::prelude::quote_in;
+use genco::prelude::rust;
+use genco::prelude::FormatInto;
+use genco::prelude::Rust;
+
+pub fn generate_field_def<'a>(field: &'a Field) -> impl FormatInto<Rust> + 'a {
+    quote_fn!(
+        $(field.name.clone()): $(field.field_type.rust_type()),
+    )
+}
+
+pub fn generate_message_code<'a>(message: &'a Message) -> impl FormatInto<Rust> + 'a {
+    quote_fn!(
+    struct $(&message.name) {$['\r']
+    $(for field in &message.fields =>
+        $[' ']$(generate_field_def(field))$['\r']
+    )}$['\n']
+
+    impl $(&message.name) {$['\r']
+        jjj
+
+    }$['\n']
+    )
+}
+
+pub fn generate_code(ast: &Vec<Decl>) -> Result<String, std::fmt::Error> {
+    let mut tokens = rust::Tokens::new();
+
+    for decl in ast {
+        match decl {
+            Decl::Message(message) => quote_in!(tokens => $(generate_message_code(message))),
+            _ => {}
+        }
+    }
+
+    let mut w = FmtWriter::new(String::new());
+
+    let fmt = fmt::Config::from_lang::<Rust>()
+        .with_indentation(fmt::Indentation::Space(4))
+        .with_newline("\n");
+
+    let config = rust::Config::default()
+        // Prettier imports and use.
+        .with_default_import(rust::ImportMode::Qualified);
+
+    tokens.format_file(&mut w.as_formatter(&fmt), &config)?;
+
+    Ok(w.into_inner())
+}