Treat codepoints U+00 up to U+20 as whitespace

- See https://docwiki.embarcadero.com/RADStudio/en/Special:Search/Fundamental%20Syntactic%20Elements%20(Delphi)#The_Delphi_Character_Set

CHANGELOG.md

@@ -59,6 +59,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - `add` is no longer colorized as a keyword in the SonarQube web interface.
 - `remove` is no longer colorized as a keyword in the SonarQube web interface.
 - `variant` is no longer colorized as a keyword in the SonarQube web interface.
+- Parsing errors on unusual whitespace characters.
 
 ## [0.40.0] - 2023-01-10
 

delphi-frontend/src/main/antlr3/au/com/integradev/delphi/antlr/Delphi.g

@@ -1276,7 +1276,7 @@ COMMENT                 :  '//' ~('\n'|'\r')*                          {$channel
                           }
                         }
                         ;
-WHITESPACE              : (' '|'\t'|'\r'|'\n'|'\f')+ {$channel=HIDDEN;}
+WHITESPACE              : ('\u0000'..'\u0020' | '\u3000')+ {$channel=HIDDEN;}
                         ;
 UnicodeBOM              : '\uFEFF' {$channel=HIDDEN;}
                         ;

delphi-frontend/src/test/java/au/com/integradev/delphi/antlr/GrammarTest.java

@@ -237,4 +237,9 @@ void testEmptyFileShouldThrow() {
                     DelphiFileUtils.mockConfig()))
         .isInstanceOf(DelphiFileConstructionException.class);
   }
+
+  @Test
+  void testUnusualWhitespace() {
+    parseFile("UnusualWhitespace.pas");
+  }
 }