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RuleBuilder#numberize_references should check LHS and RHS for dupli…
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…cation

Before this commit, LHS is not included into check list of `candidates`.
Therefore `$args` in the code below is valid reference and converted
to the reference to LHS (`args`).
This commit change it to check both of LHS and RHS when resolve the named
reference, so that the code is reported as duplicated reference.

```
args : ...
     | args ',' arg_splat
         {
             $$ = rest_arg_append(p, $args, $arg_splat, &@$);
         }
     ;
```
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@yui-knk
yui-knk committed Jan 17, 2024
1 parent 7186fe0 commit a158cb8
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Showing 2 changed files with 116 additions and 32 deletions.
13 changes: 9 additions & 4 deletions lib/lrama/grammar/rule_builder.rb
View file
Original file line number Diff line number Diff line change
Expand Up @@ -173,11 +173,12 @@ def numberize_references

token.references.each do |ref|
ref_name = ref.name
if ref_name && ref_name != '$'
if lhs.referred_by?(ref_name)

if ref_name
if ref_name == '$'
ref.name = '$'
else
candidates = rhs.each_with_index.select {|token, i| token.referred_by?(ref_name) }
candidates = ([lhs] + rhs).each_with_index.select {|token, _i| token.referred_by?(ref_name) }

if candidates.size >= 2
token.invalid_ref(ref, "Referring symbol `#{ref_name}` is duplicated.")
Expand All @@ -187,7 +188,11 @@ def numberize_references
token.invalid_ref(ref, "Referring symbol `#{ref_name}` is not found.")
end

ref.index = referring_symbol[1] + 1
if referring_symbol[1] == 0 # Refers to LHS
ref.name = '$'
else
ref.index = referring_symbol[1]
end
end
end

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135 changes: 107 additions & 28 deletions spec/lrama/grammar/rule_builder_spec.rb
View file
Original file line number Diff line number Diff line change
Expand Up @@ -314,37 +314,116 @@ class : keyword_class tSTRING keyword_end { $classes = $1; }
end

context "component name is duplicated" do
let(:text) { "class : keyword_class tSTRING tSTRING keyword_end { $class = $tSTRING; }" }
let(:grammar_file) { Lrama::Lexer::GrammarFile.new(path, text) }
let(:location_1) { Lrama::Lexer::Location.new(grammar_file: grammar_file, first_line: 1, first_column: 0, last_line: 1, last_column: 5) }
let(:location_2) { Lrama::Lexer::Location.new(grammar_file: grammar_file, first_line: 1, first_column: 8, last_line: 1, last_column: 21) }
let(:location_3) { Lrama::Lexer::Location.new(grammar_file: grammar_file, first_line: 1, first_column: 22, last_line: 1, last_column: 29) }
let(:location_4) { Lrama::Lexer::Location.new(grammar_file: grammar_file, first_line: 1, first_column: 30, last_line: 1, last_column: 37) }
let(:location_5) { Lrama::Lexer::Location.new(grammar_file: grammar_file, first_line: 1, first_column: 38, last_line: 1, last_column: 49) }
let(:location_6) { Lrama::Lexer::Location.new(grammar_file: grammar_file, first_line: 1, first_column: 51, last_line: 1, last_column: 71) }
let(:token_1) { Lrama::Lexer::Token::Ident.new(s_value: "class", location: location_1) }
let(:token_2) { Lrama::Lexer::Token::Ident.new(s_value: "keyword_class", location: location_2) }
let(:token_3) { Lrama::Lexer::Token::Ident.new(s_value: "tSTRING", location: location_3) }
let(:token_4) { Lrama::Lexer::Token::Ident.new(s_value: "tSTRING", location: location_4) }
let(:token_5) { Lrama::Lexer::Token::Ident.new(s_value: "keyword_end", location: location_5) }
let(:token_6) { Lrama::Lexer::Token::UserCode.new(s_value: " $class = $tSTRING; ", location: location_6) }
context "components in RHS are duplicated" do
let(:y) do
<<-GRAMMAR
%token keyword_class
%token tSTRING
%token keyword_end
it "raises error" do
rule_builder.lhs = token_1
rule_builder.add_rhs(token_2)
rule_builder.add_rhs(token_3)
rule_builder.add_rhs(token_4)
rule_builder.add_rhs(token_5)
rule_builder.user_code = token_6
rule_builder.complete_input
%%
expected = <<-TEXT
parse.y:1:61: Referring symbol `tSTRING` is duplicated.
class : keyword_class tSTRING tSTRING keyword_end { $class = $tSTRING; }
^^^^^^^^
TEXT
program: class
;
expect { rule_builder.send(:preprocess_references) }.to raise_error(expected)
class: keyword_class tSTRING tSTRING keyword_end { $class = $tSTRING; }
;
GRAMMAR
end

it "raises error" do
expected = <<-TEXT
parse.y:10:60: Referring symbol `tSTRING` is duplicated.
class: keyword_class tSTRING tSTRING keyword_end { $class = $tSTRING; }
^^^^^^^^
TEXT
expect { Lrama::Parser.new(y, "parse.y").parse }.to raise_error(expected)
end
end

context "components in LHS and RHS are duplicated" do
let(:y) do
<<-GRAMMAR
%token keyword_class
%token tSTRING
%token keyword_end
%%
program: class
;
class: class tSTRING keyword_end { $class = $tSTRING; }
;
GRAMMAR
end

it "raises error" do
expected = <<-TEXT
parse.y:10:35: Referring symbol `class` is duplicated.
class: class tSTRING keyword_end { $class = $tSTRING; }
^^^^^^
TEXT
expect { Lrama::Parser.new(y, "parse.y").parse }.to raise_error(expected)
end
end

context "components in LHS and RHS are duplicated by alias name" do
let(:y) do
<<-GRAMMAR
%token keyword_class
%token tSTRING
%token keyword_end
%%
program: klass
;
klass[class]: class tSTRING keyword_end { $class = $tSTRING; }
;
GRAMMAR
end

it "raises error" do
expected = <<-TEXT
parse.y:10:42: Referring symbol `class` is duplicated.
klass[class]: class tSTRING keyword_end { $class = $tSTRING; }
^^^^^^
TEXT
expect { Lrama::Parser.new(y, "parse.y").parse }.to raise_error(expected)
end
end

context "components in LHS and RHS are duplicated by alias name" do
let(:y) do
<<-GRAMMAR
%token keyword_class
%token tSTRING
%token keyword_end
%%
program: klass
;
klass[class]: Klass[class] tSTRING keyword_end { $class = $tSTRING; }
;
GRAMMAR
end

it "raises error" do
expected = <<-TEXT
parse.y:10:49: Referring symbol `class` is duplicated.
klass[class]: Klass[class] tSTRING keyword_end { $class = $tSTRING; }
^^^^^^
TEXT
expect { Lrama::Parser.new(y, "parse.y").parse }.to raise_error(expected)
end
end
end
end
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