diff --git a/lib/lrama/grammar.rb b/lib/lrama/grammar.rb
index 699c99dd..b58b4901 100644
--- a/lib/lrama/grammar.rb
+++ b/lib/lrama/grammar.rb
@@ -156,6 +156,8 @@ def prepare
       fill_symbol_printer
       fill_symbol_error_token
       @symbols.sort_by!(&:number)
+      compute_nullable
+      compute_first_set
     end
 
     # TODO: More validation methods
@@ -167,6 +169,61 @@ def validate!
       validate_rule_lhs_is_nterm!
     end
 
+    def find_symbol_by_s_value(s_value)
+      @symbols.find do |sym|
+        sym.id.s_value == s_value
+      end
+    end
+
+    def find_symbol_by_s_value!(s_value)
+      find_symbol_by_s_value(s_value) || (raise "Symbol not found: #{s_value}")
+    end
+
+    def find_symbol_by_id(id)
+      @symbols.find do |sym|
+        sym.id == id || sym.alias_name == id.s_value
+      end
+    end
+
+    def find_symbol_by_id!(id)
+      find_symbol_by_id(id) || (raise "Symbol not found: #{id}")
+    end
+
+    def find_symbol_by_number!(number)
+      sym = @symbols[number]
+
+      raise "Symbol not found: #{number}" unless sym
+      raise "[BUG] Symbol number mismatch. #{number}, #{sym}" if sym.number != number
+
+      sym
+    end
+
+    def find_rules_by_symbol!(sym)
+      find_rules_by_symbol(sym) || (raise "Rules for #{sym} not found")
+    end
+
+    def find_rules_by_symbol(sym)
+      @sym_to_rules[sym.number]
+    end
+
+    def terms_count
+      terms.count
+    end
+
+    def terms
+      @terms ||= @symbols.select(&:term?)
+    end
+
+    def nterms_count
+      nterms.count
+    end
+
+    def nterms
+      @nterms ||= @symbols.select(&:nterm?)
+    end
+
+    private
+
     def compute_nullable
       @rules.each do |rule|
         case
@@ -251,61 +308,6 @@ def compute_first_set
       end
     end
 
-    def find_symbol_by_s_value(s_value)
-      @symbols.find do |sym|
-        sym.id.s_value == s_value
-      end
-    end
-
-    def find_symbol_by_s_value!(s_value)
-      find_symbol_by_s_value(s_value) || (raise "Symbol not found: #{s_value}")
-    end
-
-    def find_symbol_by_id(id)
-      @symbols.find do |sym|
-        sym.id == id || sym.alias_name == id.s_value
-      end
-    end
-
-    def find_symbol_by_id!(id)
-      find_symbol_by_id(id) || (raise "Symbol not found: #{id}")
-    end
-
-    def find_symbol_by_number!(number)
-      sym = @symbols[number]
-
-      raise "Symbol not found: #{number}" unless sym
-      raise "[BUG] Symbol number mismatch. #{number}, #{sym}" if sym.number != number
-
-      sym
-    end
-
-    def find_rules_by_symbol!(sym)
-      find_rules_by_symbol(sym) || (raise "Rules for #{sym} not found")
-    end
-
-    def find_rules_by_symbol(sym)
-      @sym_to_rules[sym.number]
-    end
-
-    def terms_count
-      terms.count
-    end
-
-    def terms
-      @terms ||= @symbols.select(&:term?)
-    end
-
-    def nterms_count
-      nterms.count
-    end
-
-    def nterms
-      @nterms ||= @symbols.select(&:nterm?)
-    end
-
-    private
-
     def setup_rules
       @rule_builders.each do |builder|
         builder.setup_rules
diff --git a/lib/lrama/parser.rb b/lib/lrama/parser.rb
index 101830fd..1284d479 100644
--- a/lib/lrama/parser.rb
+++ b/lib/lrama/parser.rb
@@ -678,8 +678,6 @@ def parse
     reset_precs
     do_parse
     @grammar.prepare
-    @grammar.compute_nullable
-    @grammar.compute_first_set
     @grammar.validate!
     @grammar
   end
diff --git a/parser.y b/parser.y
index c7d4e68e..82057156 100644
--- a/parser.y
+++ b/parser.y
@@ -434,8 +434,6 @@ def parse
     reset_precs
     do_parse
     @grammar.prepare
-    @grammar.compute_nullable
-    @grammar.compute_first_set
     @grammar.validate!
     @grammar
   end