Add noline grammar statement to skip emitting #line directives

CHANGELOG.md

@@ -1,5 +1,9 @@
 ## v4.5.0
 
+### New Features
+
+- Add `noline` grammar statement to skip emitting `#line` directives
+
 ### Fixes
 
 - Fix #line reset directives

doc/user_guide.md

@@ -383,6 +383,27 @@ module proj.parser;
 If a module statement is not present, then the generated D module will not
 contain a module statement and the default module name will be used.
 
+##> `noline` statement - disabling `#line` directives
+
+By default, Propane emits `#line` directives into the generated output around
+user code blocks.
+These directives instruct the compiler to report any warnings or errors in the
+user code using the file name and line number of the original grammar file,
+rather than the generated output file.
+This makes it easier to locate the source of a compiler diagnostic in the
+grammar file.
+
+The `noline` statement disables the emission of these `#line` directives.
+
+```
+noline;
+```
+
+When the `noline` statement is present, user code blocks are copied to the
+generated output without any surrounding `#line` directives.
+This can be useful when debugging the generated parser itself, or when the
+`#line` directives interfere with other tooling.
+
 ##> `on_tree_node` statement -  custom initialization of a token tree node
 
 The `on_token_node` statement can be used to provide code that initializes

lib/propane/grammar.rb

@@ -88,6 +88,7 @@ class Propane
       elsif parse_rule_statement!
       elsif parse_code_block_statement!
       elsif parse_prefix_statement!
+      elsif parse_noline_statement!
       else
         if @input.size > 25
           @input = @input.slice(0..20) + "..."
@@ -306,11 +307,13 @@ class Propane
       if md = consume!(/<<([a-z]*)(.*?)>>\n/m)
         name, code = md[1..2]
         code = code.chomp
+        unless @noline
           if code.start_with?("\n")
             code = %[#line #{@line_number + 1} "#{@filename}"#{code}\n#linereset\n]
           else
             code = %[#line #{@line_number} "#{@filename}"\n#{code}\n#linereset\n]
           end
+        end
         if @code_blocks[name]
           @code_blocks[name] += code
         else
@@ -328,6 +331,13 @@ class Propane
       end
     end
 
+    def parse_noline_statement!
+      if md = consume!(/noline\s*;/)
+        @noline = true
+        true
+      end
+    end
+
     def parse_pattern!
       if md = consume!(%r{/})
         pattern = ""
@@ -352,11 +362,13 @@ class Propane
     def parse_code_block!
       if md = consume!(/<<(.*?)>>\n/m)
         code = md[1].chomp
+        unless @noline
           if code.start_with?("\n")
             code = %[#line #{@line_number + 1} "#{@filename}"#{code}\n#linereset\n]
           else
             code = %[#line #{@line_number} "#{@filename}"\n#{code}\n#linereset\n]
           end
+        end
         code
       end
     end

spec/propane/grammar_spec.rb

@@ -133,6 +133,41 @@ EOF
       expect(o.code).to eq %[#line 7 "test.propane"\n  writeln("Hello there");\n#linereset\n]
     end
 
+    it "does not emit #line directives with noline statement" do
+      input = <<EOF
+noline;
+
+token code1 <<
+  a = b;
+  return c;
+>>
+
+token code2 <<
+  writeln("Hello there");
+>>
+
+tokenid token_with_no_pattern;
+
+prefix myparser_;
+EOF
+      grammar = Grammar.new(input, "test.propane")
+      expect(grammar.prefix).to eq "myparser_"
+
+      o = grammar.tokens.find {|token| token.name == "code1"}
+      expect(o).to_not be_nil
+
+      o = grammar.patterns.find {|pattern| pattern.token == o}
+      expect(o).to_not be_nil
+      expect(o.code).to eq %[\n  a = b;\n  return c;]
+
+      o = grammar.tokens.find {|token| token.name == "code2"}
+      expect(o).to_not be_nil
+
+      o = grammar.patterns.find {|pattern| pattern.token == o}
+      expect(o).to_not be_nil
+      expect(o.code).to eq %[\n  writeln("Hello there");]
+    end
+
     it "supports mode labels" do
       input = <<EOF
 token a;