parseYaml: Parse YAML Markup (generic)

In rappster/yamlr: Processes YAML markup

Description

Parses YAML markup as identified by getYaml.

Usage

parseYaml(yaml, strict = FALSE, ...)

Arguments

yaml	Signature argument. Object containing identified YAML markup as returned by getYaml.
strict	logical. TRUE: error if no YAML markup could be identified (which in turn results in field original in class ObjectReferencedYaml.S3 being empty); FALSE: no error if no YAML markup could be identified.
...	Further arguments to be passed to subsequent functions/methods.

YAML syntax

Note that the YAML statement for specifying object references must be as follows:

object-ref: {id: {id}, where: {where}, as: {id-ref}}

Note that elements where and as are optional and that spaces are required between each syntax component. While the lack of spaces will cause a parsing error in yaml.load, additional spaces do not casue any trouble.

Example for valid YAML statements

• object-ref: {id: x_1, where: .GlobalEnv, as: ref_1}

• object-ref: {id: x_1, where: .GlobalEnv}

• object-ref: {id: x_1}

• object-ref: { id: x_1, where : .GlobalEnv, as: ref_1 }

See the official http://www.yaml.org/ for more details about YAML

Author(s)

Janko Thyson [e-mail]

References

http://github.com/Rappster/yamlr

See Also

parseYaml-function-YamlContext.ObjectReference.S3-method

Examples

## Not run: 

##------------------------------------------------------------------------------
## From function //
##------------------------------------------------------------------------------

## Get //
yaml <- getYaml(
  from = function() {
    "object-ref: {id: x_1, where: .GlobalEnv, as: ref_1}"
  },
  ctx = YamlContext.ObjectReference.S3()
)

## Parse //
yaml <- parseYaml(yaml = yaml)

## Inspect //
yaml
yaml$original
yaml$parsed
yaml$index
yaml$src

## Condition handling //
yaml <- getYaml(
  from = function() {
    "Invalid YAML markup"
  },
  ctx = YamlContext.ObjectReference.S3()
)
yaml$original

try(getYaml(
  from = function() {
    "Invalid YAML markup"
  },
  ctx = YamlContext.ObjectReference.S3(),
  strict = TRUE
))

##------------------------------------------------------------------------------
## From expression //
##------------------------------------------------------------------------------

yaml <- getYaml(
  from = captureExpression({
    "object-ref: {id: x_1, where: .GlobalEnv, as: ref_1}"
    ref_1
  }),
  ctx = YamlContext.ObjectReference.S3()
)
yaml <- parseYaml(yaml = yaml)

## Inspect //
yaml
yaml$original
yaml$parsed
yaml$index
yaml$src


## End(Not run)

rappster/yamlr documentation built on May 27, 2019, 2:02 a.m.