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Re: [Yaml-core] Top level block scalar without indentation
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From: KOSEKI K. <ko...@gm...> - 2013-04-14 04:30:44
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Hi Oren, Thanks for the clarification! I created a ticket for this. http://pyyaml.org/ticket/288 > auto-detect does not return 0, it returns at least 1, but since we start > with -1 this results with an overall 0 indentation (since production 207 > uses -1 and not 0). Is YAML 1.1 same? In YAML 1.1 spec, the rule [117] max(-1, 0) set n = 0. So I think [166] detect(m) must return 0, not 1.. [117] c-l+block-scalar(n) ::= c-l+folded(max(n,0)) | c-l+literal(max(n,0)) [175] c-l+literal(n) ::= c-b-block-header(literal,m,t) l-literal-content(n+m,t) I'm not sure I'm understanding these parametered production rules.. Anyway, I hope I can use top level block scalar with libyaml. 2013/4/14 Oren Ben-Kiki <or...@be...>: > Well, example 9.5 is pretty explicit in what the spec says. Note that the > auto-detect does not return 0, it returns at least 1, but since we start > with -1 this results with an overall 0 indentation (since production 207 > uses -1 and not 0). > > The same logic holds for both of your samples; example 9.3 shows an > unindented plain at the top level. > > Oren. > > > > On Sat, Apr 13, 2013 at 2:10 PM, KOSEKI Kengo <ko...@gm...> wrote: >> >> Hi, >> >> I noticed that LibYAML doesn't parse block scalar without indentation. >> >> Sample: 1 >> --- >> XXX >> YYY >> ZZZ >> >> Sample: 2 >> --- | >> XXX >> YYY >> ZZZ >> >> I expected that these samples would be parsed like this: >> >> [{"Sample": 1}, "XXX YYY ZZZ"] >> [{"Sample": 2}, "XXX\nYYY\nZZZ\n"] >> >> LibYAML can parse Sample 1 but not Sample 2. >> >> $ ./run-parser Sample1.yaml >> [1] Parsing 'Sample1.yaml': SUCCESS (11 events) >> >> $ ./run-parser Sample2.yaml >> [1] Parsing 'Sample2.yaml': FAILURE (10 events) >> >> PyYAML returned error. >> >> expected '<document start>', but found '<scalar>' >> >> >> I checked some implementations. The results are: >> >> Syck (YAML 1.0) - Ruby >> Sample1 ... PASS >> Sample2 ... PASS >> >> YAML.pm (YAML 1.0) - Perl >> Sample1 ... FAIL >> Sample2 ... PASS >> >> PyYAML (YAML 1.1) - Python / LibYAML >> Sample1 ... PASS >> Sample2 ... FAIL >> >> Psych (YAML 1.1) - Ruby / LibYAML >> Sample1 ... PASS >> Sample2 ... FAIL >> >> SnakeYAML (YAML 1.1) - Java / based on LibYAML >> Sample1 ... PASS >> Sample2 ... FAIL >> >> JS-YAML (YAML 1.2) - JavaScript >> Sample1 ... PASS >> Sample2 ... PASS >> >> Yamerl (YAML 1.2) - Erlang >> Sample1 ... PASS >> Sample2 ... PASS >> >> >> My questions are: >> >> (1) Which parsers are implemented properly, at this point? >> (2) Is there possibility that LibYAML support Sample2? >> At YAML 1.1 trunk or future 1.2 branch? >> >> >> In YAML 1.0 spec, Example 4.21 says: >> >> --- | >> Usually top level nodes are not indented. >> >> In YAML 1.2 spec, Example 9.5 says: >> >> %YAML 1.2 >> --- | >> %!PS-Adobe-2.0 >> ... >> >> %YAML 1.2 >> --- >> !!str "%!PS-Adobe-2.0\n" >> ... >> >> I couldn't find an example like these in the YAML 1.1 spec. >> It may be determined by [161] detect(m) being able to return 0 or not. >> >> >> I found this message. >> >> * http://osdir.com/ml/text.yaml.general/2008-07/msg00001.html >> >> > The spec requires that continuation lines of a flow scalar are indented >> > with at least one space. LibYAML relaxes this rule by allowing >> > multi-line flow scalars not to be indented, >> >> So I realized that the Sample1 result was came from relaxing >> the spec. But how about the block scalar, Sample 2? >> >> >> I think this notation is important, because this enable to append >> metadata to the plain text. >> >> An email will be represented like this. >> >> Date: 2013-04-13 20:10:53+09:00 >> Subject: Top level block scalar without indentation >> From: ko...@gm... >> To: yam...@li... >> --- | >> Hi, >> I noticed that ... >> >> >> Using template engine to generate HTML. >> >> title: YAML block scalar >> template: blog >> published: 2013-04-13 >> --- | >> <article> >> <h1>xxxxxx</h1> >> <pre> >> Here must >> be written in >> multi lines. >> </pre> >> </article> >> >> >> Best regards, >> >> -- >> koseki >> >> >> ------------------------------------------------------------------------------ >> Precog is a next-generation analytics platform capable of advanced >> analytics on semi-structured data. The platform includes APIs for building >> apps and a phenomenal toolset for data science. Developers can use >> our toolset for easy data analysis & visualization. Get a free account! >> http://www2.precog.com/precogplatform/slashdotnewsletter >> _______________________________________________ >> Yaml-core mailing list >> Yam...@li... >> https://lists.sourceforge.net/lists/listinfo/yaml-core > > -- koseki |