Allow 0-length allocs.

1 files changed, 7 insertions, 3 deletions

diff --git a/bytecode/src/bytecode.rs b/bytecode/src/bytecode.rs
index 313b2fb..e784d57 100644
--- a/bytecode/src/bytecode.rs
+++ b/bytecode/src/bytecode.rs
@@ -152,7 +152,11 @@ impl Interpreter {
     fn alloc(&mut self, dest: Local, size: Arg) -> Result<(), String> {
         let n = self.read_arg(size).to_int()?;
         if n < 0 {
-            return Err(String::from("tried to allocate negative memory"));
+            return Err(String::from("need a positive argument to alloc"));
+        }
+        if n == 0 {
+            self.set_arg(dest, Value(0));
+            return Ok(());
         }
         let p = self
             .heap
@@ -163,8 +167,8 @@ impl Interpreter {
 
     fn alloc_bytevector(&mut self, dest: Local, size: Arg) -> Result<(), String> {
         let n = self.read_arg(size).to_int()?;
-        if n < 0 {
-            return Err(String::from("tried to allocate negative memory"));
+        if n <= 0 {
+            return Err(String::from("need a positive argument to alloc_bytevector"));
         }
         let p = self
             .heap