Add the 'unset' built-in command

Add the 'unset' command to remove global environment variable
definitions from the shell.

1 files changed, 4 insertions, 1 deletions

diff --git a/src/poem/anthology.rs b/src/poem/anthology.rs
index 94b5f6b..2a2f62a 100644
--- a/src/poem/anthology.rs
+++ b/src/poem/anthology.rs
@@ -7,7 +7,9 @@ use crate::compose::Environment;
 use crate::poem::Verse;
 
 /// A static list of all the built-in commands
-static INDEX: [&str; 6] = ["alias", "cd", "exit", "export", "source", "unalias"];
+static INDEX: [&str; 7] = [
+    "alias", "cd", "exit", "export", "source", "unalias", "unset",
+];
 
 /// Lookup the index of a built-in command
 ///
@@ -30,6 +32,7 @@ pub fn incant(verse: &Verse, index: usize, env: &mut Environment) -> i32 {
         "export" => export::incant(verse),
         "source" => source::incant(verse, env),
         "unalias" => alias::unincant(verse, &mut env.aliases),
+        "unset" => export::unincant(verse),
         _ => unreachable!(),
     }
 }