refactor(tvix/repl): Abstract out REPL command handling r/8188

Prepare for introducing additional REPL commands by splitting out
the *parsing* of the repl commands, which returns a new ReplCommand
type, from the actual *handling* of the commands.

Change-Id: If81a53c1e2d90204d26ce3bb2ea9eebf7bb3fd51
Reviewed-on: https://cl.tvl.fyi/c/depot/+/11734
Autosubmit: aspen <root@gws.fyi>
Tested-by: BuildkiteCI
Reviewed-by: flokli <flokli@flokli.de>

1 files changed, 26 insertions, 10 deletions

diff --git a/tvix/cli/src/repl.rs b/tvix/cli/src/repl.rs
index 8dde9d9bfdc0..7d29ae3d2c83 100644
--- a/tvix/cli/src/repl.rs
+++ b/tvix/cli/src/repl.rs
@@ -1,4 +1,5 @@
-use std::{path::PathBuf, rc::Rc};
+use std::path::PathBuf;
+use std::rc::Rc;
 
 use rustyline::{error::ReadlineError, Editor};
 use tvix_glue::tvix_store_io::TvixStoreIO;
@@ -13,6 +14,22 @@ fn state_dir() -> Option<PathBuf> {
     path
 }
 
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub enum ReplCommand<'a> {
+    Expr(&'a str),
+    Explain(&'a str),
+}
+
+impl<'a> ReplCommand<'a> {
+    pub fn parse(input: &'a str) -> Self {
+        if let Some(without_prefix) = input.strip_prefix(":d ") {
+            Self::Explain(without_prefix)
+        } else {
+            Self::Expr(input)
+        }
+    }
+}
+
 #[derive(Debug)]
 pub struct Repl {
     /// In-progress multiline input, when the input so far doesn't parse as a complete expression
@@ -69,24 +86,23 @@ impl Repl {
                         &line
                     };
 
-                    let res = if let Some(without_prefix) = input.strip_prefix(":d ") {
-                        interpret(
+                    let res = match ReplCommand::parse(input) {
+                        ReplCommand::Expr(input) => interpret(
                             Rc::clone(&io_handle),
-                            without_prefix,
+                            input,
                             None,
                             args,
-                            true,
+                            false,
                             AllowIncomplete::Allow,
-                        )
-                    } else {
-                        interpret(
+                        ),
+                        ReplCommand::Explain(input) => interpret(
                             Rc::clone(&io_handle),
                             input,
                             None,
                             args,
-                            false,
+                            true,
                             AllowIncomplete::Allow,
-                        )
+                        ),
                     };
 
                     match res {