test expr parsing

src/expr/mod.rs

@@ -12,7 +12,7 @@ use yz_string_utils::StrLexerBase;
 #[derive(Clone, Debug, PartialEq, Eq, PartialOrd, Ord, Hash)]
 pub struct Link(pub u16, pub Box<[u16]>);
 
-#[derive(Clone, Debug)]
+#[derive(Clone, Debug, PartialEq)]
 pub enum Expr<L> {
     Const(f64),
     Link(L),
@@ -56,7 +56,7 @@ impl<L: Clone + Eq + Ord> Expr<L> {
 /// A system of PDEs and monitors (outputs)
 ///
 /// LHS is always the first derivative to time (it is not possible to refer to time derivatives on RHS)
-#[derive(Clone, Debug)]
+#[derive(Clone, Debug, PartialEq)]
 pub struct System {
     pub vs: Vec<Expr<Link>>,
 
@@ -97,7 +97,7 @@ impl System {
     }
 }
 
-#[derive(Clone, Debug, thiserror::Error)]
+#[derive(Clone, Debug, PartialEq, thiserror::Error)]
 pub enum ParseError {
     #[error("unexpected end of expression")]
     EmptyExpr,
@@ -151,6 +151,9 @@ impl ParseLink for Link {
         } else {
             let mut new_slb = (*slb).clone();
             let var = new_slb.consume_select(|i| i.is_ascii_digit());
+            if var.is_empty() {
+                return Ok(None);
+            }
             let var = var.parse::<u16>()?;
             if !new_slb.inp.starts_with('_') {
                 return Ok(None);
@@ -254,7 +257,7 @@ fn parse_expr_final<L: Clone + ParseLink>(slb: &mut StrLexerBase) -> Result<Expr
 ```
 %vs
 # u_t + 0.11 u_x = 0
-0; -0.11 0_0_
+0; prod(-0.11, 0_0_)
 
 %mons
 # monitor u @ 1 + sin(t)
@@ -349,3 +352,31 @@ pub fn parse_system(s: &str) -> Result<System, ((usize, usize), ParseError)> {
 
     Ok(ret)
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn example0_fail() {
+        assert_eq!(parse_system("
+%vs
+# u_t + 0.11 u_x = 0
+0; -0.11 0_0_
+
+        "), Err(((3, 8), ParseError::InvalidTrail)));
+    }
+
+    #[test]
+    fn example0() {
+        println!("{:?}", parse_system("
+%vs
+# u_t + 0.11 u_x = 0
+0; prod(-0.11, 0_0_)
+
+%mons
+# monitor u @ 1 + sin(t)
+0_; sum(1.0, sin(.))
+        ").unwrap());
+    }
+}