scalar: implement 'scalar list'

The produced list simply consists of those repositories registered under
the multi-valued `scalar.repo` config setting in the user's Git config.

Signed-off-by: Derrick Stolee <[email protected]>
Signed-off-by: Johannes Schindelin <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: derrickstolee

contrib/scalar/scalar.c

@@ -251,6 +251,16 @@ static int unregister_dir(void)
 	return res;
 }
 
+static int cmd_list(int argc, const char **argv)
+{
+	if (argc != 1)
+		die(_("`scalar list` does not take arguments"));
+
+	if (run_git("config", "--global", "--get-all", "scalar.repo", NULL) < 0)
+		return -1;
+	return 0;
+}
+
 static int cmd_register(int argc, const char **argv)
 {
 	struct option options[] = {
@@ -337,6 +347,7 @@ static struct {
 	const char *name;
 	int (*fn)(int, const char **);
 } builtins[] = {
+	{ "list", cmd_list },
 	{ "register", cmd_register },
 	{ "unregister", cmd_unregister },
 	{ NULL, NULL},

contrib/scalar/scalar.txt

@@ -8,6 +8,7 @@ scalar - an opinionated repository management tool
 SYNOPSIS
 --------
 [verse]
+scalar list
 scalar register [<enlistment>]
 scalar unregister [<enlistment>]
 
@@ -28,11 +29,19 @@ an existing Git worktree with Scalar whose name is not `src`, the enlistment
 will be identical to the worktree.
 
 The `scalar` command implements various subcommands, and different options
-depending on the subcommand.
+depending on the subcommand. With the exception of `list`, all subcommands
+expect to be run in an enlistment.
 
 COMMANDS
 --------
 
+List
+~~~~
+
+list::
+	List enlistments that are currently registered by Scalar. This
+	subcommand does not need to be run inside an enlistment.
+
 Register
 ~~~~~~~~