Comment:
It bugs the heck out of me that they kept the ASI between `return` and an
expression on a separate line. I find it hard to believe that is not always a
bug. But I guess we should obey the standard...
Questions:
1. Did you mean to leave the NoLineTerminator commented out of the #include and
#pragma productions?
2. Should/could the pattern `[LOOKAHEAD({Sc()}) ";"]` be a named production,
for better readability?
3. It appears we have no Java 1.3 or 1.4 code any more. Should we just remove
all mention of those from the build.xml files (and just name the build
directory `build` instead of `build.1.5`)?
Issues:
1. This is surely not your bug, but when I first compiled, I got some
serialization errors about caches building the solo consoles. I am pretty sure
I had done an `ant clean` before starting, which I would have _hoped_ would
nuke any caches. Either I missed that step, or `ant clean` is deficient. We
should try to determine which is the case.
Otherwise, approved!
On 2011-02-02, at 14:17, André Bargull wrote:
> I'll update svn.openlaszlo.org/vendor/ and the wiki pages [1,2] later.
>
> [1] http://wiki.openlaszlo.org/SubversionBuildInstructions#Install_JavaCC
> [2]
> http://wiki.openlaszlo.org/NativeWindows7SubversionBuildInstructions#Install_javacc
>
>
> Change bargull-20110202-U3G by bargull@Bargull02 on 2011-02-02 17:03:34
> in /home/anba/src/svn/openlaszlo/trunk
> for http://svn.openlaszlo.org/openlaszlo/trunk
>
> Summary: Upgrade to JavaCC5, fix ASI bugs in parser
>
> New Features: LPP-8788 (We should use a more modern version of JavaCC)
>
> Bugs Fixed: LPP-9714 (Parser does not enfore no-line-terminator in
> break/continue/throw/postfix-op statements), LPP-9719 (Semicolon after
> do-while creates empty statement), LPP-9720 (Newline in multi-line comment
> not treated as newline for ASI), LPP-9721 (TypeIdentifier() should enforce
> NoLineTerminator before Nullable()/NonNullable()), LPP-9722 (Multi-line
> comment not handled when computing ASI)
>
> Technical Reviewer: ptw, dda
> QA Reviewer: (pending)
>
> Overview:
> JavaCC 5 has got a bug with javacode non-terminals, somehow the tokenstream
> isn't rewinded properly in a (deeply?) nested syntactic lookahead if used in
> conjunction with javacode non-terminals (e.g. see lookahead for
> ModifiedDefinition() in Directive() and the Sc() non-terminal). Even using a
> no-op javacode non-terminal broke the parser (JAVACODE void Nop ()
> {/*empty*/}). Because of that reason I had to re-implement the whole optional
> semicolon mechanism in the parser. While doing this rework, I've encountered
> a couple of bugs (LPP-9714, LPP-9719, LPP-9720, LPP-9721, LPP-9722).
>
>
> Details:
> All Sc() non-terminals for optional semicolons have been rewritten to use a
> semantic lookahead: [LOOKAHEAD({Sc()}) ";"]
> The new Sc() function simply returns `true` if the next token in the stream
> is a semicolon, this semicolon will then simply be consumed. If the next
> token is not a semicolon, but an acceptable choice for automatic semicolon
> insertion (ASI), Sc() returns `false`. So the lookahead is unsuccessful and
> by that the optional block [...] is not processed any further. If the next
> token is neither a semicolon nor an acceptable choice for ASI, a parser
> exception is thrown.
>
> JavaCC cannot infer the content a javacode non-terminal, therefore it
> couldn't warn for possible ambiguities in the grammar after Sc() calls. As
> the old Sc() non-terminal is gone, I had to add additional lookaheads to
> resolve these ambiguities. See CallExpression(), AdditiveExpression(),
> RelationalExpression() productions.
>
> LPP-9714 (no-line-terminator rule):
> The ECMAScript grammar has got restricted productions for the
> PostfixExpression, ContinueStatement, BreakStatement, ThrowStatement and
> ReturnStatement productions. For these productions, line terminators are
> strictly prohibited. This restriction was only implemented for the
> ReturnStatement, it's now implemented for the other productions as well. The
> pattern used to implement the restriction is simply:
> [LOOKAHEAD(NonTerminal(), {NoLineTerminator()}) NonTerminal()]. So a
> combination of syntactic and semantic lookahead: if the next token(s) can be
> parsed as NonTerminal() and there are no intervening newlines, consume the
> tokens, otherwise just proceed. I've added an extra function to produce a
> nice error message for the ThrowStatement production, so it's easier for the
> user to understand what's going wrong when she added a newline after the
> `throw` statement. The default error message by JavaCC is pretty useless
> here: Encountered "" at line 1, column 61. Was expecting one of:!
(empty list here)
>
> LPP-9719 (do-while loop):
> Just added the optional semicolon predicate for the do-while loop in
> IterationStatement().
>
> LPP-9720 (newline in multi-line comment):
> Scan for newlines in multi-line comments, they count as newlines for the
> syntactic grammar, cf. ECMAScript 5, 7.4 Comments
>
> LPP-9721 (restriced production for TypeIdentifier):
> TypeIdentifier was not a restricted production, but it should be, otherwise
> "var x:Boolean \n !x;", where \n denotes a line break, is not parsed as "var
> x:Boolean; !x;".
>
> LPP-9722 (multi-line comment for ASI):
> The (now removed) optionalSc() function just used the first special token,
> but special tokens are chained, e.g. consider multiple single-line and
> multi-line comments appearing next to each other. Therefore it's necessary to
> loop over the specialToken field, just like it's now done in
> NoLineTerminator().
>
> Token.java:
> JavaCC 5 requires a new interface in Token: Token.newToken(int, String).
>
> TestParserASI.java:
> JUnit test case for LPP-9714, LPP-9719, LPP-9720, LPP-9721, LPP-9722
>
> build.xml:
> - update 1.4 -> 1.5
> - comment out org/openlaszlo/iv/flash/context package, this was recently
> discussed on laszlo-dev
> - explicitly add EDU/oswego package for build, sometimes my ant doesn't pick
> it up, so make it explicit
> - add TestParserASI to the "test" target
>
>
> Tests:
> TestParserASI test case, lfc compiles, smokecheck and alldata (swf10,
> dhtml)x(Firefox, Opera, Safari, IE)
>
> (Don't forget to download and install JavaCC 5 and update your JAVACC_HOME
> environment variable accordingly!)
>
> Files:
> M WEB-INF/lib/javacc.jar
> M WEB-INF/lps/server/build.xml
> A WEB-INF/lps/server/src/org/openlaszlo/test/TestParserASI.java
> M WEB-INF/lps/server/sc/src/org/openlaszlo/sc/Parser.jjt
> M WEB-INF/lps/server/sc/src/org/openlaszlo/sc/parser/Token.java
>
> Changeset:
> http://svn.openlaszlo.org/openlaszlo/patches/bargull-20110202-U3G.tar
>
