From 862d73eabe498e1acdb6e6a7bd114de1bb3edc1b Mon Sep 17 00:00:00 2001
From: Chris Guidry <chris@theguidrys.us>
Date: Thu, 30 Jul 2026 21:16:09 -0400
Subject: [PATCH] Allow d3 as a valid die size

Chris reversed the earlier ruling after checking the SRD: d3 appears
92 times, always as "regains 1d3 expended charges daily at dawn" on
magic item recharge tables, so it's a real 5e die size, not shorthand
for a halved d6. Valid sizes are now 2, 3, 4, 6, 8, 10, 12, 20, and 100.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01CUXjWo1zGFhdJUig1hcQGf
---
 src/dice.rs       | 11 ++++++-----
 src/dice_tests.rs | 21 ++++++++++++++-------
 2 files changed, 20 insertions(+), 12 deletions(-)

diff --git a/src/dice.rs b/src/dice.rs
index 0b75be4..5c99a7a 100644
--- a/src/dice.rs
+++ b/src/dice.rs
@@ -9,7 +9,7 @@
 //! `r>N` reroll a die until the condition stops matching, and `miN` sets a
 //! floor on each die's value. Rerolls and minimums settle before keep and
 //! drop choose which dice count. A die size must be one this grammar
-//! knows: 2, 4, 6, 8, 10, 12, 20, or 100.
+//! knows: 2, 3, 4, 6, 8, 10, 12, 20, or 100.
 
 use rand::RngExt;
 
@@ -19,9 +19,10 @@ use rand::RngExt;
 /// produces a roll instead of hanging.
 const MAX_REROLLS: u32 = 100;
 
-/// The die sizes a 5e table rolls. Anything else, including `d3` (a halved
-/// d6 in the SRD's shorthand), is not a die this grammar accepts.
-const VALID_SIDES: [u32; 8] = [2, 4, 6, 8, 10, 12, 20, 100];
+/// The die sizes a 5e table rolls, including `d3` for the SRD's charge
+/// tables ("regains 1d3 expended charges daily at dawn"). Anything else
+/// is not a die this grammar accepts.
+const VALID_SIDES: [u32; 9] = [2, 3, 4, 6, 8, 10, 12, 20, 100];
 
 /// Notation that failed to parse, with a reason worded so that whatever
 /// wrote the notation can correct it and try again.
@@ -296,7 +297,7 @@ fn parse_group(
             notation: original.to_string(),
             reason: format!(
                 "a die size of `{sides}` in `{text}` is not a valid 5e die size; \
-use 2, 4, 6, 8, 10, 12, 20, or 100 (`%`)"
+use 2, 3, 4, 6, 8, 10, 12, 20, or 100 (`%`)"
             ),
         });
     }
diff --git a/src/dice_tests.rs b/src/dice_tests.rs
index 64f16ed..9ca00ea 100644
--- a/src/dice_tests.rs
+++ b/src/dice_tests.rs
@@ -62,6 +62,11 @@ fn a_standard_die_size_of_two() {
     parses_to("d2", notation("d2", vec![Term::Group(group(1, 2))]));
 }
 
+#[test]
+fn a_standard_die_size_of_three() {
+    parses_to("1d3", notation("1d3", vec![Term::Group(group(1, 3))]));
+}
+
 #[test]
 fn percentile_die_is_100_sided() {
     parses_to("d%", notation("d%", vec![Term::Group(group(1, 100))]));
@@ -511,6 +516,15 @@ fn rolling_a_single_die() {
     assert_eq!(result.total, 17);
 }
 
+#[test]
+fn rolling_a_d3() {
+    let result = rolled("1d3", 0);
+
+    assert_eq!(result.dice[0].sides, 3);
+    assert_eq!(result.dice[0].value, 3);
+    assert_eq!(result.total, 3);
+}
+
 #[test]
 fn rolling_multiple_dice() {
     let result = rolled("3d6", 0);
@@ -784,13 +798,6 @@ fn a_zero_die_size_is_an_error() {
     assert!(error.reason.contains("die size"));
 }
 
-#[test]
-fn d3_is_not_a_standard_die_size() {
-    let error = parse("d3").unwrap_err();
-    assert!(error.reason.contains("die size"));
-    assert!(error.reason.contains('3'));
-}
-
 #[test]
 fn an_unsupported_die_size_is_an_error() {
     let error = parse("1d7").unwrap_err();
-- 
2.51.2