Add the 'alias' built-in command

The shell now has support for aliases (via alias foo=bar). The 'unalias'
command is also available to remove aliases. Finally,
Environment::aliases was changed to be a HashMap<String, String>,
instead of a Vec<String>.

Since the verse's verb might change (for instance, it is an environment
variable, or an alias), add another check in Poem::recite, which simply
continues, instead of running the spellchecker, if the verb is empty.

1 files changed, 47 insertions, 0 deletions

diff --git a/src/poem/anthology/alias.rs b/src/poem/anthology/alias.rs
new file mode 100644
index 0000000..6a8e739
--- /dev/null
+++ b/src/poem/anthology/alias.rs
@@ -0,0 +1,47 @@
+use crate::poem::Verse;
+use std::collections::HashMap;
+
+pub fn incant(verse: &Verse, aliases: &mut HashMap<String, String>) -> i32 {
+    match verse.clause() {
+        Some(clause) => {
+            for stanza in clause {
+                let (key, val) = match stanza.split_once("=") {
+                    Some((key, val)) => (key, val),
+                    None => continue,
+                };
+                aliases.insert(String::from(key), String::from(val));
+            }
+        }
+        None => {
+            for (key, val) in aliases {
+                if key.contains(' ') && val.contains(' ') {
+                    println!("'{}'='{}'", key, val);
+                } else if key.contains(' ') {
+                    println!("'{}'={}", key, val);
+                } else if val.contains(' ') {
+                    println!("{}='{}'", key, val);
+                } else if val.is_empty() {
+                    println!("{}=''", key);
+                } else {
+                    println!("{}={}", key, val);
+                }
+            }
+        }
+    }
+    0
+}
+
+pub fn unincant(verse: &Verse, aliases: &mut HashMap<String, String>) -> i32 {
+    match verse.clause() {
+        Some(clause) => {
+            for stanza in clause {
+                aliases.remove(&stanza);
+            }
+        }
+        None => {
+            eprintln!("unalias: not enough arguments");
+            return 1;
+        }
+    }
+    0
+}