Table of Contents

1 library(yaml): Process YAML data

This module parses YAML serialized data into a Prolog term with structure that is compatible with the JSON library. This library is a wrapper around the C library libyaml. This library forms the basis of the YAML support in several languages and thus guarantees compatibility of our YAML support with other languages.

[det]yaml_read(+Input, -DOM)

Parse Input to a YALM DOM. The DOM representation uses the following mapping:

• A YAML sequence is mapped to a Prolog List.
• A YAML mapping is mapped to a Prolog dict.
• Untagged scalars follow the implicit tag rules defined by YAML, providing numbers (int, float and special floats), null and the booleans true and false. Other untagged values are returned as a Prolog string. Tagged values are returned as tag(Tag, String) which is processed by yalm_tagged/3. This internal predicate calls the user hook yaml:tagged/3 with the same arguments and, if the hook fails, provides the following defaults:
  • !!binary converts the Base64 to a string of bytes.
  • !!str explicitly keeps a string
  • !!null translates "null" to null
  • !!bool translates to true and false
  • !!int translates to an integer
  • !!float translates to a float
  • Anything else is returned as tag(Tag, String)

Input

is one of (1) a stream, (2) a term string(Data) or (3) a file name.

[det]yaml_write(+Out:stream, +DOM)

[det]yaml_write(+Out:stream, +DOM, +Options)

Emit a YAML DOM object as a serialized YAML document to the stream Out. Options processed are:

canonical(+Boolean)

Use canonical representation. Default is false.

unicode(+Boolean)

Use unicode Default is true.

implicit(+Boolean)

Use implicit or explicit representation. Currently only affects the opening and closing the document. Default is true. Use false for embedded documents.

factorize(+Boolean)

If true, minimize the term by factoring out common structures and use &anchor and *anchor. Factorization is always used if DOM is a cyclic term.

[semidet,multifile]tagged(+Tag, ?String, ?Value)

Hook that allows convering !!tag values to be decoded or encoded.

Index

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tagged/3

yaml_read/2

yaml_write/2

yaml_write/3