Simplify normalize_rules

The first goal of Lrama was generating parse.c file same with what Bison generates. For this goal, it was needed to set symbol number and rule number with same order with Bison. However Lrama has a lot of tests now. Then it’s not needed to generate completely same parse.c file with Bison.
ruby · Dec 24, 2023 · 2e2aa78 · 2e2aa78
1 parent c30569b
commit 2e2aa78
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Showing 3 changed files with 22 additions and 47 deletions.
diff --git a/lib/lrama/grammar.rb b/lib/lrama/grammar.rb
@@ -359,29 +359,8 @@ def append_special_symbols
       @accept_symbol = term
     end
 
-    # 1. Add $accept rule to the top of rules
-    # 2. Extract action in the middle of RHS into new Empty rule
-    # 3. Append id and extract action then create Rule
-    #
-    # Bison 3.8.2 uses different orders for symbol number and rule number
-    # when a rule has actions in the middle of a rule.
-    #
-    # For example,
-    #
-    # `program: $@1 top_compstmt`
-    #
-    # Rules are ordered like below,
-    #
-    # 1 $@1: ε
-    # 2 program: $@1 top_compstmt
-    #
-    # Symbols are ordered like below,
-    #
-    # 164 program
-    # 165 $@1
-    #
     def normalize_rules
-      # 1. Add $accept rule to the top of rules
+      # Add $accept rule to the top of rules
       accept = @accept_symbol
       eof = @eof_symbol
       lineno = @rule_builders.first ? @rule_builders.first.line : 0
@@ -390,8 +369,8 @@ def normalize_rules
       setup_rules
 
       @rule_builders.each do |builder|
-        # Extract actions in the middle of RHS into new rules.
         builder.midrule_action_rules.each do |rule|
+          add_nterm(id: rule._lhs)
           @rules << rule
         end
 
@@ -404,10 +383,6 @@ def normalize_rules
           add_nterm(id: rule._lhs, tag: rule.lhs_tag)
           @rules << rule
         end
-
-        builder.midrule_action_rules.each do |rule|
-          add_nterm(id: rule._lhs)
-        end
       end
 
       @rules.sort_by!(&:id)

diff --git a/spec/lrama/parser_spec.rb b/spec/lrama/parser_spec.rb
@@ -1700,11 +1700,11 @@ class : keyword_class { code 1 } tSTRING { code 2 } keyword_end { code 3 }
       grammar = Lrama::Parser.new(y, "parse.y").parse
 
       expect(grammar.nterms.sort_by(&:number)).to match_symbols([
-        Sym.new(id: T::Ident.new(s_value: "$accept"), alias_name: nil, number: 11, tag: nil,                                 term: false, token_id: 0, nullable: false),
-        Sym.new(id: T::Ident.new(s_value: "program"), alias_name: nil, number: 12, tag: nil,                                 term: false, token_id: 1, nullable: false),
-        Sym.new(id: T::Ident.new(s_value: "class"),   alias_name: nil, number: 13, tag: T::Tag.new(s_value: "<i>"), term: false, token_id: 2, nullable: false),
-        Sym.new(id: T::Ident.new(s_value: "$@1"),     alias_name: nil, number: 14, tag: nil,                                 term: false, token_id: 3, nullable: true),
-        Sym.new(id: T::Ident.new(s_value: "$@2"),     alias_name: nil, number: 15, tag: nil,                                 term: false, token_id: 4, nullable: true),
+        Sym.new(id: T::Ident.new(s_value: "$accept"), alias_name: nil, number: 11, tag: nil,                        term: false, token_id: 0, nullable: false),
+        Sym.new(id: T::Ident.new(s_value: "program"), alias_name: nil, number: 12, tag: nil,                        term: false, token_id: 1, nullable: false),
+        Sym.new(id: T::Ident.new(s_value: "$@1"),     alias_name: nil, number: 13, tag: nil,                        term: false, token_id: 2, nullable: true),
+        Sym.new(id: T::Ident.new(s_value: "$@2"),     alias_name: nil, number: 14, tag: nil,                        term: false, token_id: 3, nullable: true),
+        Sym.new(id: T::Ident.new(s_value: "class"),   alias_name: nil, number: 15, tag: T::Tag.new(s_value: "<i>"), term: false, token_id: 4, nullable: false),
       ])
       expect(grammar.rules).to eq([
         Rule.new(

diff --git a/spec/lrama/states_spec.rb b/spec/lrama/states_spec.rb
@@ -993,46 +993,46 @@ class    go to state 5
 
     $default  reduce using rule 1 ($@1)
 
-    program  go to state 1
-    $@1      go to state 2
+    $@1      go to state 1
+    program  go to state 2
 
 
 State 1
 
-    0 $accept: program • "EOI"
+    2 program: $@1 • expr
+    3 expr: • tNUMBER
 
-    "EOI"  shift, and go to state 3
+    tNUMBER  shift, and go to state 3
 
+    expr  go to state 4
 
-State 2
 
-    2 program: $@1 • expr
-    3 expr: • tNUMBER
+State 2
 
-    tNUMBER  shift, and go to state 4
+    0 $accept: program • "EOI"
 
-    expr  go to state 5
+    "EOI"  shift, and go to state 5
 
 
 State 3
 
-    0 $accept: program "EOI" •
+    3 expr: tNUMBER •
 
-    $default  accept
+    $default  reduce using rule 3 (expr)
 
 
 State 4
 
-    3 expr: tNUMBER •
+    2 program: $@1 expr •
 
-    $default  reduce using rule 3 (expr)
+    $default  reduce using rule 2 (program)
 
 
 State 5
 
-    2 program: $@1 expr •
+    0 $accept: program "EOI" •
 
-    $default  reduce using rule 2 (program)
+    $default  accept
 
 
         STR