Fix argument sinks

Fixes #886.

2 files changed, 19 insertions, 10 deletions

diff --git a/src/eval/args.rs b/src/eval/args.rs
index 8617bd93..bea2baa1 100644
--- a/src/eval/args.rs
+++ b/src/eval/args.rs
@@ -62,14 +62,23 @@ impl Args {
     }
 
     /// Consume n positional arguments if possible.
-    pub fn consume(&mut self, n: usize) -> SourceResult<EcoVec<Arg>> {
-        if n > self.items.len() {
+    pub fn consume(&mut self, n: usize) -> SourceResult<Vec<Arg>> {
+        let mut list = vec![];
+
+        let mut i = 0;
+        while i < self.items.len() && list.len() < n {
+            if self.items[i].name.is_none() {
+                list.push(self.items.remove(i));
+            } else {
+                i += 1;
+            }
+        }
+
+        if list.len() < n {
             bail!(self.span, "not enough arguments");
         }
-        let vec = self.items.to_vec();
-        let (left, right) = vec.split_at(n);
-        self.items = right.into();
-        Ok(left.into())
+
+        Ok(list)
     }
 
     /// Consume and cast the first positional argument.
diff --git a/src/eval/scope.rs b/src/eval/scope.rs
index f2207188..76633bf2 100644
--- a/src/eval/scope.rs
+++ b/src/eval/scope.rs
@@ -38,20 +38,20 @@ impl<'a> Scopes<'a> {
 
     /// Try to access a variable immutably.
     pub fn get(&self, var: &str) -> StrResult<&Value> {
-        Ok(std::iter::once(&self.top)
+        std::iter::once(&self.top)
             .chain(self.scopes.iter().rev())
             .chain(self.base.map(|base| base.global.scope()))
             .find_map(|scope| scope.get(var))
-            .ok_or(eco_format!("unknown variable: {}", var))?)
+            .ok_or_else(|| eco_format!("unknown variable: {}", var))
     }
 
     /// Try to access a variable immutably in math.
     pub fn get_in_math(&self, var: &str) -> StrResult<&Value> {
-        Ok(std::iter::once(&self.top)
+        std::iter::once(&self.top)
             .chain(self.scopes.iter().rev())
             .chain(self.base.map(|base| base.math.scope()))
             .find_map(|scope| scope.get(var))
-            .ok_or(eco_format!("unknown variable: {}", var))?)
+            .ok_or_else(|| eco_format!("unknown variable: {}", var))
     }
 
     /// Try to access a variable mutably.