Fix value computation for multi-line strings (issue 22993)

Fix value computation for multi-line strings (issue 22993)

R=paulberry@google.com

Committed: https://code.google.com/p/dart/source/detail?r=44722

[Brian Wilkerson, 2015-03-26 16:50:33]

brianwilkerson@google.com changed reviewers:
+ paulberry@google.com

[Paul Berry, 2015-03-26 17:59:13]

lgtm

https://codereview.chromium.org/1034953002/diff/1/pkg/analyzer/lib/src/genera...
File pkg/analyzer/lib/src/generated/parser.dart (right):

https://codereview.chromium.org/1034953002/diff/1/pkg/analyzer/lib/src/genera...
pkg/analyzer/lib/src/generated/parser.dart:3504: } else if (currentChar != 0x09
&& currentChar != 0x20 && currentChar != 0x5C) {
As discussed in person, this doesn't match the VM behavior for some corner cases
(nor does the VM behavior match the spec).  The VM appears to decode the string
first, then strip out leading whitespace, then do string interpolation.  I
haven't investigated what dart2js does.

IMHO, it would be reasonable to land this CL as is for now, since it's going to
take some time to get clarification from Gilad & co. about what behavior is
actually intended for the corner cases.


Here are some of the corner cases I investigated, and how I believe the VM
currently interprets them:

'''\\
foo''' => '\\\nfoo'

'''\t
foo''' => 'foo'

r'''\
foo''' => '\\\nfoo'

r'''\t
foo''' => '\\t\nfoo'

'''\x20
foo''' => 'foo'

String x = ' ';
'''$x
foo''' => ' \nfoo'

[Brian Wilkerson, 2015-03-26 21:32:46]

I added more tests and made it compatible with dart2js. PTAL

[Paul Berry, 2015-03-26 21:40:52]

lgtm with one minor correction.

https://codereview.chromium.org/1034953002/diff/40001/pkg/analyzer/test/gener...
File pkg/analyzer/test/generated/parser_test.dart (right):

https://codereview.chromium.org/1034953002/diff/40001/pkg/analyzer/test/gener...
pkg/analyzer/test/generated/parser_test.dart:8878: parse4("parseStringLiteral",
"'''\\ \\\na'''");
Missing the "r" character on this line.

[Brian Wilkerson, 2015-03-26 21:45:21]

https://codereview.chromium.org/1034953002/diff/40001/pkg/analyzer/test/gener...
File pkg/analyzer/test/generated/parser_test.dart (right):

https://codereview.chromium.org/1034953002/diff/40001/pkg/analyzer/test/gener...
pkg/analyzer/test/generated/parser_test.dart:8878: parse4("parseStringLiteral",
"'''\\ \\\na'''");
Good catch! Done.

[Brian Wilkerson, 2015-03-26 21:45:38]

Committed patchset #3 (id:40001) manually as 44722 (presubmit successful).