Antlr backend - quotation marks in bracket expressions are escaped when they shouldn't

[fonfalleh]

It seems the only characters that should be escaped in bracket expressions in regexes are ], \, and -. I'm not sure if this means that there needs to be different escaping in different contexts.
https://github.com/antlr/antlr4/blob/master/doc/lexer-rules.md#lexer-rule-elements

Example token rule that generates broken code (not by any means good or correct, I just noticed that the resulting lexer file doesn't work) :
token NoteToken ["abcdefgr"]({"es"} | {"is"})*["\',"]*(digit)*["."]* ;
results in the following line in the Lexer.g4 file
NoteToken : [abcdefgr]('e''s'|'i''s')*[\',]*DIGIT*'.'*;
which generates the following when building:
warning(156): lily/lilyLexer.g4:83:38: invalid escape sequence \'

The build also complains about the following line:
STRINGTEXT : ~[\"\\] -> more;

bnfc/source/src/BNFC/Backend/Java/CFtoAntlr4Lexer.hs

Line 157 in 3ca7211

, "STRINGTEXT : ~[\\\"\\\\] -> more;"

The build works as expected when removing the extra backslashes as follows:
NoteToken : [abcdefgr]('e''s'|'i''s')*[',]*DIGIT*'.'*;
...
STRINGTEXT : ~["\\] -> more;

---

Sidenote:
I first thought this could be related to this line, referencing RegToJLex.hs instead of RegToAntlrLexer.hs, but it seems the reference is correct, even if it's confusing naming.

bnfc/source/src/BNFC/Backend/Java/CFtoAntlr4Lexer.hs

Line 150 in 3ca7211

[ text name <> " : " <> text (printRegJLex exp) <> ";"

Export from RegToAntlrLexer:

bnfc/source/src/BNFC/Backend/Java/RegToAntlrLexer.hs

Line 1 in 3ca7211

module BNFC.Backend.Java.RegToAntlrLexer (printRegJLex, escapeChar) where

[andreasabel]

It seems that the regular expression printer does not apply special printing rules when printing content in bracketed expressions, but maybe it should, according to the rules you quoted above:

The following escaped characters are interpreted as single special characters: \n, \r, \b, \t, \f, \uXXXX, and \u{XXXXXX}. To get ], \, or - you must escape them with \.
(From https://github.com/antlr/antlr4/blob/master/doc/lexer-rules.md#lexer-rule-elements)

The problematic lines in BNFC are thus:

bnfc/source/src/BNFC/Backend/Java/RegToAntlrLexer.hs

Line 79 in 3ca7211

RAlts str -> prPrec i 3 (concat [["["],prt 0 str,["]"]])

bnfc/source/src/BNFC/Backend/Java/RegToAntlrLexer.hs

Lines 69 to 72 in 3ca7211

	RMinus RAny reg@(RChar _)
	-> prPrec i 3 (concat [["~["],prt 0 reg,["]"]])
	RMinus RAny (RAlts str)
	-> prPrec i 3 (concat [["~["],prt 0 str,["]"]])

There, instead of calling the prt function recursively, a special print function for content inside brackets should be called.

[andreasabel]

@fonfalleh : Can you test if PR #321 works for you?

[fonfalleh]

@fonfalleh : Can you test if PR #321 works for you?

Seems to work, thanks! 👍

[andreasabel]

Great!