test: added boilerplate and tests for coproduct parsing, type checking and evaluation

4 files changed, 26 insertions, 0 deletions

diff --git a/src/sexp/case.rs b/src/sexp/case.rs
index 4c2c7ba..cc643f3 100644
--- a/src/sexp/case.rs
+++ b/src/sexp/case.rs
@@ -52,6 +52,18 @@ impl SExp {
      *     ])
      * );
      * ```
+     *
+     * Coproducts must be handled individually:
+     * ```rust
+     * use myslip::r#type::Type::*;
+     * use myslip::sexp::{SExp::*, SLeaf::*, util::*};
+     *
+     * assert_eq!(
+     *     scons(Coprod, scons(Ty(Boolean), scons(2, Nil)))
+     *         .matches_pat(&scons(Inr, scons(var("x"), Nil))),
+     *     Some(vec![(Var("x".to_string()), Atom(Int(2)))])
+     * );
+     * ```
      */
     pub fn matches_pat(&self, pat: &SExp) -> Option<Vec<(SLeaf, SExp)>> {
 	match (self, pat) {
diff --git a/src/sexp/display.rs b/src/sexp/display.rs
index ec1b421..703bda3 100644
--- a/src/sexp/display.rs
+++ b/src/sexp/display.rs
@@ -28,6 +28,9 @@ impl fmt::Display for SLeaf {
 	    RestPat(s) => format!("..{s}"),
             Quote  => "quote".to_string(),
             Vector => "vector".to_string(),
+            Coprod => "coprod".to_string(),
+            Inl    => "inl".to_string(),
+            Inr    => "inr".to_string(),
             Concat => "<>".to_string(),
 	    Print  => "print".to_string(),
             Let    => "let".to_string(),
diff --git a/src/sexp/mod.rs b/src/sexp/mod.rs
index 1a90f52..14731dd 100644
--- a/src/sexp/mod.rs
+++ b/src/sexp/mod.rs
@@ -34,6 +34,9 @@ pub enum SLeaf {
 
     Quote,
     Vector,
+    Coprod,
+    Inl,
+    Inr,
 
     Let,
 
diff --git a/src/sexp/step.rs b/src/sexp/step.rs
index 59b201c..3168c5b 100644
--- a/src/sexp/step.rs
+++ b/src/sexp/step.rs
@@ -297,6 +297,14 @@ impl SExp {
     /// assert_eq!(exp, expshould);
     /// let exp = exp.and_then(|e| e.step());
     /// assert_eq!(exp, Ok(Atom(True)));
+    ///
+    /// let exp = "case (coprod Bool (+ 1 2)) ((inl b) (if b 1 0)) ((inr x) (- x 1))";
+    /// let exp = parse_to_ast(exp);
+    /// let exp = exp.and_then(|e| e.step());
+    /// let expshould = parse_to_ast("case (coprod Bool 3) ((inl b) (if b 1 0)) ((inr x) (- x 1))");
+    /// assert_eq!(exp, expshould);
+    /// let exp = exp.and_then(|e| e.step());
+    /// assert_eq!(exp, Ok(scons(Sub, scons(3, scons(1, Nil)))));
     /// ```
     ///
     /// Shadowing: