Rearchitect CommandTree

- CommandTree::Term is now terminal only with respect to searching for
the debug-handling function to execute, it can have children that only
the tab-completion code cares about

- CommandTree::NonTerminal never has a function associated with it, if the
processing of a list of repl debug commands gets to a NonTerminal leaf,
there's just nothing to do

schala-repl/src/repl/command_tree.rs

@@ -6,25 +6,25 @@ pub type BoxedCommandFunction = Box<(fn(&mut Repl, &[&str]) -> Option<String>)>;
 pub enum CommandTree {
   Terminal {
     name: String,
+    children: Vec<CommandTree>,
     help_msg: Option<String>,
-    function: Option<BoxedCommandFunction>,
+    function: BoxedCommandFunction,
   },
   NonTerminal {
     name: String,
     children: Vec<CommandTree>,
     help_msg: Option<String>,
-    function: Option<BoxedCommandFunction>,
   },
   Top(Vec<CommandTree>),
 }
 
 impl CommandTree {
-  pub fn term(s: &str, help: Option<&str>) -> CommandTree {
-    CommandTree::Terminal {name: s.to_string(), help_msg: help.map(|x| x.to_string()), function: None }
+  pub fn nonterm_no_further_tab_completions(s: &str, help: Option<&str>) -> CommandTree {
+    CommandTree::NonTerminal {name: s.to_string(), help_msg: help.map(|x| x.to_string()), children: vec![] }
   }
 
-  pub fn term_with_function(s: &str, help: Option<&str>, func: BoxedCommandFunction) -> CommandTree {
-    CommandTree::Terminal {name: s.to_string(), help_msg: help.map(|x| x.to_string()), function: Some(func) }
+  pub fn term_with_function(s: &str, help: Option<&str>, function: BoxedCommandFunction) -> CommandTree {
+    CommandTree::Terminal {name: s.to_string(), help_msg: help.map(|x| x.to_string()), function, children: vec![] }
   }
 
   pub fn nonterm(s: &str, help: Option<&str>, children: Vec<CommandTree>) -> CommandTree {
@@ -32,10 +32,10 @@ impl CommandTree {
       name: s.to_string(),
       help_msg: help.map(|x| x.to_string()),
       children,
-      function: None,
     }
   }
 
+  /*
   pub fn nonterm_with_function(s: &str, help: Option<&str>, children: Vec<CommandTree>, func: BoxedCommandFunction) -> CommandTree {
     CommandTree::NonTerminal {
       name: s.to_string(),
@@ -44,6 +44,7 @@ impl CommandTree {
       function: Some(func),
     }
   }
+  */
 
   pub fn get_cmd(&self) -> &str {
     match self {

schala-repl/src/repl/mod.rs

@@ -112,11 +112,8 @@ impl Repl {
           };
         },
         CommandTree::Terminal { name, function, .. } => {
-          break match function.as_ref() {
-            Some(f) => Ok((f, idx)),
-            None => Err(format!("No action specified for: {:?}", commands)),
-          };
-        }
+          break Ok((function, idx));
+        },
       }
     }
   }
@@ -200,7 +197,7 @@ impl Repl {
     };
 
     let passes_directives: Vec<CommandTree> = pass_names.iter()
-      .map(|pass_name| { CommandTree::term(pass_name, None) })
+      .map(|pass_name| { CommandTree::nonterm_no_further_tab_completions(pass_name, None) })
       .collect();
 
     CommandTree::Top(vec![
@@ -237,20 +234,20 @@ impl Repl {
           CommandTree::nonterm("show", None, passes_directives.clone()),
           CommandTree::nonterm("hide", None, passes_directives.clone()),
           CommandTree::nonterm("timing", None, vec![
-            CommandTree::term("on", None),
-            CommandTree::term("off", None),
+            CommandTree::nonterm_no_further_tab_completions("on", None),
+            CommandTree::nonterm_no_further_tab_completions("off", None),
           ])
         ]
       ),
       CommandTree::nonterm("lang",
         Some("switch between languages, or go directly to a langauge by name"),
         vec![
-          CommandTree::term("next", None),
-          CommandTree::term("prev", None),
+          CommandTree::nonterm_no_further_tab_completions("next", None),
+          CommandTree::nonterm_no_further_tab_completions("prev", None),
           CommandTree::nonterm("go", None, vec![]),
         ]
       ),
-      CommandTree::term("doc", Some("Get language-specific help for an item")),
+      CommandTree::nonterm_no_further_tab_completions("doc", Some("Get language-specific help for an item")),
     ])
   }
 }
@@ -339,7 +336,7 @@ impl<T: Terminal> Completer<T> for TabCompleteHandler {
           let new_ptr: Option<&CommandTree> = command_tree.and_then(|cm| match cm {
             CommandTree::Top(children) => children.iter().find(|c| c.get_cmd() == s),
             CommandTree::NonTerminal { children, .. } => children.iter().find(|c| c.get_cmd() == s),
-            CommandTree::Terminal { .. } => None,
+            CommandTree::Terminal { children, .. } => children.iter().find(|c| c.get_cmd() == s),
           });
           command_tree = new_ptr;
         }