wip

Author: Mr-Leshiy

rust/cbork-cddl-parser/src/lib.rs

@@ -1,7 +1,7 @@
 //! A parser for CDDL, utilized for parsing in accordance with RFC 8610.
 
 mod parser;
-mod processor;
+mod preprocessor;
 
 pub use crate::parser::cddl_test;
 
@@ -23,6 +23,7 @@ pub enum Extension {
 ///
 /// - If there is an issue with parsing the CDDL input.
 pub fn validate_cddl(input: &mut String, extension: &Extension) -> anyhow::Result<()> {
-    parser::parse_cddl(input, extension)?;
+    let ast = parser::parse_cddl(input, extension)?;
+    preprocessor::process_ast(ast)?;
     Ok(())
 }

rust/cbork-cddl-parser/src/preprocessor/mod.rs

@@ -0,0 +1,66 @@
+//! A CDDL AST preprocessor.
+//! First processing step, which takes a CDDL `AST` and returning a list of CDDL
+//! `Expression`.
+//!
+//! Preprocessor steps:
+//! - Resolve #include and #import directives, by just adding the imported rules into the
+//!   final expression list
+//! - Resolves all generics by taking the generic arguments and substituting it.
+
+use anyhow::{anyhow, ensure};
+use pest::{
+    iterators::{Pair, Pairs},
+    RuleType,
+};
+
+use crate::parser::{cddl, rfc_8610, rfc_9165, Ast};
+
+/// Processes the AST.
+pub(crate) fn process_ast(ast: Ast) -> anyhow::Result<()> {
+    match ast {
+        Ast::Rfc8610(ast) => {
+            let _exprs = process_root(ast, rfc_8610::Rule::cddl, rfc_8610::Rule::expr)?;
+        },
+        Ast::Rfc9165(ast) => {
+            let _exprs = process_root(ast, rfc_9165::Rule::cddl, rfc_9165::Rule::expr)?;
+        },
+        Ast::Cddl(ast) => {
+            let exprs = process_root(ast, cddl::Rule::cddl, cddl::Rule::expr)?;
+
+            for expr in exprs {
+                println!("{:?}", expr.as_rule());
+            }
+        },
+    }
+    Ok(())
+}
+
+/// Process the root rule of the AST.
+/// Returns a vector of expressions of the underlying AST.
+fn process_root<R: RuleType>(
+    mut ast: Pairs<'_, R>, root_rule: R, expr_rule: R,
+) -> anyhow::Result<Vec<Pair<'_, R>>> {
+    let ast_root = ast.next().ok_or(anyhow!("Empty AST."))?;
+    ensure!(
+        ast_root.as_rule() == root_rule && ast.next().is_none(),
+        "AST must have only one root rule, which must be a `{root_rule:?}` rule."
+    );
+    Ok(ast_root
+        .into_inner()
+        .filter(|pair| pair.as_rule() == expr_rule)
+        .collect())
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::parser::parse_cddl;
+
+    #[test]
+    fn it_works() {
+        let mut cddl = include_str!("../../tests/cddl/valid_rfc8610_simple_1.cddl").to_string();
+
+        let ast = parse_cddl(&mut cddl, &crate::Extension::CDDL).unwrap();
+        process_ast(ast).unwrap();
+    }
+}