wip

lib/lrama/grammar/reference.rb

@@ -2,11 +2,12 @@ module Lrama
   class Grammar
     # type: :dollar or :at
     # name: String (e.g. $$, $foo, $expr.right)
-    # index: Integer (e.g. $1)
+    # number: Integer (e.g. $1)
+    # index:
     # ex_tag: "$<tag>1" (Optional)
-    class Reference < Struct.new(:type, :name, :index, :ex_tag, :first_column, :last_column, keyword_init: true)
+    class Reference < Struct.new(:type, :name, :number, :index, :ex_tag, :first_column, :last_column, keyword_init: true)
       def value
-        name || index
+        name || number
       end
     end
   end

lib/lrama/grammar/rule_builder.rb

@@ -164,23 +164,33 @@ def numberize_references
           next unless token.is_a?(Lrama::Lexer::Token::UserCode)
 
           token.references.each do |ref|
+            # Derive number reference index from named reference
             ref_name = ref.name
             if ref_name && ref_name != '$'
               if lhs.referred_by?(ref_name)
                 ref.name = '$'
               else
-                candidates = rhs.each_with_index.select {|token, i| token.referred_by?(ref_name) }
+                candidates = referable_tokens.each_with_index.select {|token, i| token.referred_by?(ref_name) }
 
                 raise "Referring symbol `#{ref_name}` is duplicated. #{token}" if candidates.size >= 2
                 raise "Referring symbol `#{ref_name}` is not found. #{token}" unless referring_symbol = candidates.first
 
-                ref.index = referring_symbol[1] + 1
+                ref.number = referring_symbol[1] + 1
+              end
+            end
+
+            if ref.number
+              # Remapping number reference index to include non referable tokens
+              # TODO: Is it better to separate "number" of reference from actual "index" (Grammar::Reference)?
+              ref.index = number_to_index[ref.number]
+
+              if !ref.index && ref.type != :at
+                raise "Can not refer to not exist component. $#{ref.number}"
               end
             end
 
             # TODO: Need to check index of @ too?
             next if ref.type == :at
-
             if ref.index
               # TODO: Prohibit $0 even so Bison allows it?
               # See: https://www.gnu.org/software/bison/manual/html_node/Actions.html
@@ -191,6 +201,39 @@ def numberize_references
         end
       end
 
+      def referable_token?(token)
+        case token
+        when Lrama::Lexer::Token::ParserStatePop
+          false
+        when Lrama::Lexer::Token::ParserStatePush
+          false
+        when Lrama::Lexer::Token::ParserStateSet
+          false
+        else
+          true
+        end
+      end
+
+      def referable_tokens
+        rhs.select do |token|
+          referable_token?(token)
+        end
+      end
+
+      def number_to_index
+        return @number_to_index if @number_to_index
+
+        @number_to_index = [0]
+
+        rhs.each.with_index(1) do |token, i|
+          if referable_token?(token)
+            @number_to_index << i
+          end
+        end
+
+        @number_to_index
+      end
+
       def flush_user_code
         if c = @user_code
           @rhs << c

lib/lrama/lexer/token/user_code.rb

@@ -38,7 +38,7 @@ def scan_reference(scanner)
             return Lrama::Grammar::Reference.new(type: :dollar, name: "$", ex_tag: tag, first_column: start, last_column: scanner.pos - 1)
           when scanner.scan(/\$(<[a-zA-Z0-9_]+>)?(\d+)/) # $1, $2, $<long>1
             tag = scanner[1] ? Lrama::Lexer::Token::Tag.new(s_value: scanner[1]) : nil
-            return Lrama::Grammar::Reference.new(type: :dollar, index: Integer(scanner[2]), ex_tag: tag, first_column: start, last_column: scanner.pos - 1)
+            return Lrama::Grammar::Reference.new(type: :dollar, number: Integer(scanner[2]),  index: Integer(scanner[2]), ex_tag: tag, first_column: start, last_column: scanner.pos - 1)
           when scanner.scan(/\$(<[a-zA-Z0-9_]+>)?([a-zA-Z_][a-zA-Z0-9_]*)/) # $foo, $expr, $<long>program (named reference without brackets)
             tag = scanner[1] ? Lrama::Lexer::Token::Tag.new(s_value: scanner[1]) : nil
             return Lrama::Grammar::Reference.new(type: :dollar, name: scanner[2], ex_tag: tag, first_column: start, last_column: scanner.pos - 1)
@@ -51,7 +51,7 @@ def scan_reference(scanner)
           when scanner.scan(/@\$/) # @$
             return Lrama::Grammar::Reference.new(type: :at, name: "$", first_column: start, last_column: scanner.pos - 1)
           when scanner.scan(/@(\d+)/) # @1
-            return Lrama::Grammar::Reference.new(type: :at, index: Integer(scanner[1]), first_column: start, last_column: scanner.pos - 1)
+            return Lrama::Grammar::Reference.new(type: :at, number: Integer(scanner[1]), index: Integer(scanner[1]), first_column: start, last_column: scanner.pos - 1)
           when scanner.scan(/@([a-zA-Z][a-zA-Z0-9_]*)/) # @foo, @expr (named reference without brackets)
             return Lrama::Grammar::Reference.new(type: :at, name: scanner[1], first_column: start, last_column: scanner.pos - 1)
           when scanner.scan(/@\[([a-zA-Z_.][-a-zA-Z0-9_.]*)\]/) # @expr.right, @expr-right  (named reference with brackets)

sig/lrama/grammar/reference.rbs

@@ -3,14 +3,15 @@ module Lrama
     class Reference
       attr_accessor type: ::Symbol
       attr_accessor name: String
+      attr_accessor number: Integer
       attr_accessor index: Integer
       attr_accessor ex_tag: Lexer::Token?
       attr_accessor first_column: Integer
       attr_accessor last_column: Integer
       attr_accessor position_in_rhs: Integer?
 
       def initialize: (
-        type: ::Symbol, ?name: String, ?index: Integer, ?ex_tag: Lexer::Token?,
+        type: ::Symbol, ?name: String, ?number: Integer, ?index: Integer, ?ex_tag: Lexer::Token?,
         first_column: Integer, last_column: Integer,
         ?position_in_rhs: Integer?
       ) -> void

sig/lrama/grammar/rule_builder.rbs

@@ -37,6 +37,9 @@ module Lrama
       def process_rhs: (Grammar::ParameterizingRuleResolver parameterizing_resolver) -> void
       def process_parser_state_token: (Lexer::Token, String, String, Integer, Grammar::ParameterizingRuleResolver) -> void
       def numberize_references: () -> void
+      def referable_token?: (Lexer::Token) -> bool
+      def referable_tokens: () -> Array[Lexer::Token]
+      def number_to_index: () -> Array[Integer]
       def flush_user_code: () -> void
     end
   end

spec/fixtures/integration/parser_state.y

@@ -86,28 +86,28 @@ primary : NUM { printf("NUM => %d\n", $1); }
           %parser-state-push(in_class, in_class)
           cname
             {
-              printf("1. cname => %s. in_def: %s, in_class: %s.\n", $4, YY_CURRENT_STATE_IN_DEF_NAME, YY_CURRENT_STATE_IN_CLASS_NAME);
+              printf("1. cname => %s. in_def: %s, in_class: %s.\n", $cname, YY_CURRENT_STATE_IN_DEF_NAME, YY_CURRENT_STATE_IN_CLASS_NAME);
             }
           compstmt
           keyword_end
           %parser-state-pop(in_def)
           %parser-state-pop(in_class)
             {
-              printf("2. cname => %s. in_def: %s, in_class: %s.\n", $4, YY_CURRENT_STATE_IN_DEF_NAME, YY_CURRENT_STATE_IN_CLASS_NAME);
+              printf("2. cname => %s. in_def: %s, in_class: %s.\n", $2, YY_CURRENT_STATE_IN_DEF_NAME, YY_CURRENT_STATE_IN_CLASS_NAME);
             }
         | keyword_def
           %parser-state-push(in_def, in_def)
           %parser-state-push(in_class, not_in_class)
           fname
             {
-              printf("1. fname => %s. in_def: %s, in_class: %s.\n", $4, YY_CURRENT_STATE_IN_DEF_NAME, YY_CURRENT_STATE_IN_CLASS_NAME);
+              printf("1. fname => %s. in_def: %s, in_class: %s.\n", $2, YY_CURRENT_STATE_IN_DEF_NAME, YY_CURRENT_STATE_IN_CLASS_NAME);
             }
           compstmt
           keyword_end
           %parser-state-pop(in_def)
           %parser-state-pop(in_class)
             {
-              printf("2. fname => %s. in_def: %s, in_class: %s.\n", $4, YY_CURRENT_STATE_IN_DEF_NAME, YY_CURRENT_STATE_IN_CLASS_NAME);
+              printf("2. fname => %s. in_def: %s, in_class: %s.\n", $fname, YY_CURRENT_STATE_IN_DEF_NAME, YY_CURRENT_STATE_IN_CLASS_NAME);
             }
         ;
 

spec/lrama/grammar/rule_builder_spec.rb

@@ -229,7 +229,7 @@
         rule_builder.user_code = token_5
         rule_builder.complete_input
 
-        expect { rule_builder.send(:preprocess_references) }.to raise_error(/Can not refer following component\. 10 >= 4\./)
+        expect { rule_builder.send(:preprocess_references) }.to raise_error(/Can not refer to not exist component\. \$10/)
       end
     end