minor optimization: add a first set to each rule variant

1 files changed, 11 insertions, 7 deletions

diff --git a/src/grammar.zig b/src/grammar.zig
index ab51275..2169fe7 100644
--- a/src/grammar.zig
+++ b/src/grammar.zig
@@ -80,21 +80,23 @@ fn generate_first(self: *Self) void {
 		modified = false;
 
 		for (self.non_terminals) |*non_terminal| {
-			for (non_terminal.rules()) |rule| {
-				switch (rule[0]) {
+			for (non_terminal.rules()) |*rule| {
+				switch (rule.items[0]) {
 					.terminal => |t| {
 						modified = modified or !non_terminal.first.is_set(t);
 						non_terminal.first.set(t);
+						rule.first.set(t);
 					},
 
 					.non_terminal, .epsilon => {
 						var insert_epsilon = true;
 
-						for (rule) |*char| {
+						for (rule.items) |*char| {
 							switch (char.*) {
 								.terminal => |t| {
 									modified = modified or !non_terminal.first.is_set(t);
 									non_terminal.first.set(t);
+									rule.first.set(t);
 									insert_epsilon = false;
 									break;
 								},
@@ -105,6 +107,7 @@ fn generate_first(self: *Self) void {
 
 										modified = modified or (!non_terminal.first.is_set(index) and child_first);
 										non_terminal.first.set_if(index, child_first);
+										rule.first.set_if(index, child_first);
 									}
 
 									if (!first.is_set(Character.EPSILON)) {
@@ -119,6 +122,7 @@ fn generate_first(self: *Self) void {
 						if (insert_epsilon and !non_terminal.first.is_set(Character.EPSILON)) {
 							modified = true;
 							non_terminal.first.set(Character.EPSILON);
+							rule.first.set(Character.EPSILON);
 						}
 					},
 				}
@@ -135,14 +139,14 @@ fn generate_follows(self: *Self) void {
 
 		for (self.non_terminals) |*non_terminal| {
 			for (non_terminal.rules()) |rule| {
-				for (0..rule.len) |character_index| {
+				for (0..rule.items.len) |character_index| {
 
-					switch (rule[character_index]) {
+					switch (rule.items[character_index]) {
 						.non_terminal => |n| {
 							const current_non_terminal = self.non_terminal_by_id(n);
 							const ends_with_epsilon = brk: {
-								for (character_index + 1..rule.len) |peek_index| {
-									switch (rule[peek_index]) {
+								for (character_index + 1..rule.items.len) |peek_index| {
+									switch (rule.items[peek_index]) {
 										.terminal => |t| {
 											modified = modified or !current_non_terminal.follows.is_set(t);
 											current_non_terminal.follows.set(t);