Add one_indexed flag (#23)

3 files changed, 53 insertions, 0 deletions

diff --git a/src/choice.rs b/src/choice.rs
index b7a74de..5e6e679 100644
--- a/src/choice.rs
+++ b/src/choice.rs
@@ -1076,6 +1076,45 @@ mod tests {
         fn print_2_exclusive() {
             test_fn(vec!["choose", "2", "-x"], "a b c d", "c");
         }
+
+        #[test]
+        fn print_2_one_indexed() {
+            test_fn(vec!["choose", "2", "--one-indexed"], "a b c d", "b");
+        }
+
+        #[test]
+        fn print_2_to_4_one_indexed() {
+            test_fn(vec!["choose", "2:4", "--one-indexed"], "a b c d", "b c d");
+        }
+
+        #[test]
+        fn print_2_to_end_one_indexed() {
+            test_fn(vec!["choose", "2:", "--one-indexed"], "a b c d", "b c d");
+        }
+
+        #[test]
+        fn print_start_to_2_one_indexed() {
+            test_fn(vec!["choose", ":2", "--one-indexed"], "a b c d", "a b");
+        }
+
+        #[test]
+        fn print_2_to_4_one_indexed_exclusive() {
+            test_fn(
+                vec!["choose", "2:4", "--one-indexed", "-x"],
+                "a b c d",
+                "b c",
+            );
+        }
+
+        #[test]
+        fn print_4_to_2_one_indexed() {
+            test_fn(vec!["choose", "4:2", "--one-indexed"], "a b c d", "d c b");
+        }
+
+        #[test]
+        fn print_neg_4_to_2_one_indexed() {
+            test_fn(vec!["choose", "-4:2", "--one-indexed"], "a b c d", "a b");
+        }
     }
 
     mod is_reverse_range_tests {
diff --git a/src/config.rs b/src/config.rs
index 53b3cfe..a279e24 100644
--- a/src/config.rs
+++ b/src/config.rs
@@ -22,6 +22,16 @@ impl Config {
                     choice.end = choice.end - 1;
                 }
             }
+
+            if opt.one_indexed {
+                if choice.start > 0 {
+                    choice.start -= 1;
+                }
+
+                if choice.end > 0 {
+                    choice.end -= 1;
+                }
+            }
         }
 
         let separator = match Regex::new(match &opt.field_separator {
diff --git a/src/opt.rs b/src/opt.rs
index d328191..94f1236 100644
--- a/src/opt.rs
+++ b/src/opt.rs
@@ -32,6 +32,10 @@ pub struct Opt {
     #[structopt(short, long)]
     pub non_greedy: bool,
 
+    /// Index from 1 instead of 0
+    #[structopt(long)]
+    pub one_indexed: bool,
+
     /// Specify output field separator
     #[structopt(short, long, parse(from_str = parse::output_field_separator))]
     pub output_field_separator: Option<String>,