yaml / yaml-grammar

Welcome to YAML

This repository found at https://github.com/yaml/yaml contains information and pointers to all things YAML.

Links

• http://yaml.org - The YAML web site
• http://instantyaml.appspot.com/
• http://www.yamllint.com/
• http://yaml-online-parser.appspot.com/
• http://data-lint.herokuapp.com/
• http://www.kuwata-lab.com/kwalify/

yaml-grammar's Issues

Names for Rules Variables are difficult to understand in context

The spec describes 4 rule variables, n, m, c, and t.

• yaml-grammar/yaml-spec-1.2.yaml

  Line 91 in 1504782

  # n -- Current indentation level. An integer indicating the number of spaces.

• yaml-grammar/yaml-spec-1.2.yaml

  Line 93 in 1504782

  # m -- Additional indentation level. An integer indicating number of spaces.

• yaml-grammar/yaml-spec-1.2.yaml

  Line 95 in 1504782

  # c -- Current context. String that is one of:

• yaml-grammar/yaml-spec-1.2.yaml

  Line 103 in 1504782

  # t -- How to treat whitespace after a literal scalar. One of:

I find a terse, single letter, variable in the spec difficult for two reasons:

1. When looking at the rules, it is difficult to remember what each letter means. If the variables were named with a brief summary of the actual value, it would be easier to remember the actual meaning.
2. The short names make searching for usages impossible. If the names were distinct, then it would be possible to quickly find usages and the definition.

I would find the spec easier to understand if the names were more descriptive. For example:

• n — currentIndent
• m — additionalIndent
• c — currentContext
• t — whitespaceTrim

Rule prefix length - 1 or 2 characters, or more?

The spec says each rule name has a "1 or 2 character prefix".

yaml-grammar/yaml-spec-1.2.yaml

Line 57 in 1504782

# Each rule name has a 1 or 2 character prefix indicating the rule type.

However, some rules have more than 2 characters. For example, rule 062 c-ns-esc-char has 4 chars: c-ns.

Rule 201 seq-spaces appears to have no prefix.

Updating the rule names seems difficult. Perhaps the description should be updated to describe the possible prefixes?

Description for rule prefixes mentions, but does not define, `n`

The description for some of the rule prefixes mention an n variable.

yaml-grammar/yaml-spec-1.2.yaml

Lines 78 to 82 in 1504782

	# And also (where X and Y are each one of the above prefixes):
	#
	# X-Y -- Match starting with an X- match and ending with a Y- match
	# X+ -- Match X where indentation is greater than n
	# X-Y+ -- Match X-Y where indentation is greater than n

However, it is not clear what n is.

Is n supposed to be the current indentation level? So the rule could be read as "where indentation is greater than the current indentation level"? In which case, isn't this always false?

It would be helpful if n was explicitly defined, with an example (or a link to an example).

Dangling rules

Hi,

Thank you for this effort. Having this extracted grammar is much more convenient for processing.

Would you please clarify why are there "dangling rules" in the grammar - the rules that are defined but not referred from anywhere.
For example rule [008] "c-sequence-start" is never used.

Thank you,
Serge

README links broken

Multiple README links are broken.

Duplicated description for `<` and `<=` comparator rule functions

The rules for both < and <= both say First argument is less than the second.

yaml-grammar/yaml-spec-1.2.yaml

Lines 257 to 261 in 1504782

	# * (<)
	# First argument is less than the second.
	#
	# * (<=)
	# First argument is less than the second.

I presume this is a mistake, and it should be:

  #   * (<)
  #     First argument is less than the second.
  #
  #   * (<=)
-  #     First argument is less than the second.
+  #     First argument is less than or equal to the second.