# yaml(3tcl) 0.4.2 yaml "YAML processing"

## Name

yaml - YAML Format Encoder/Decoder

## Synopsis

- package require Tcl 8.5 9
- package require yaml ?0.4.2?

- ::yaml::yaml2dict ?options? txt
- ::yaml::yaml2huddle ?options? txt
- ::yaml::setOption ?options?
- ::yaml::dict2yaml dict ?indent? ?wordwrap?
- ::yaml::list2yaml list ?indent? ?wordwrap?
- ::yaml::huddle2yaml huddle ?indent? ?wordwrap?

## Description

The yaml package provides a simple Tcl-only library for parsing the YAML http://www.yaml.org/ data exchange format as specified in http://www.yaml.org/spec/1.1/.

The yaml package returns data as a Tcl dict. Either the dict package or Tcl 8.5 is required for use.

## COMMANDS

::yaml::yaml2dict ?options? txt
::yaml::yaml2huddle ?options? txt

  Parse yaml formatted text txt into a Tcl dict/huddle and return the value.

  -file

    txt is a filename of YAML-stream.

  -stream

    txt is just a YAML-stream.

  -types list

    The list is a type list for the yaml-scalar types.(e.g. !!str !!timestamp !!integer !!true ...)

         -types {timestamp integer null true false}

    In this case, if a string matched "timestamp", converted to the TCL internal timestamp.(e.g. "2001-12-15T02:59:43.1Z" => 1008385183)

  -m:true param

    The param is two elements of list for the value of true, and considered strings.

         -m:true {1 {true on + yes y}}

    In this case, the string "yes" found in YAML Stream, automatically converted 1.

  -m:false param

    The param is two elements of list for the value of false, and considered strings.

         -m:false {0 {false off - no n}}

  -m:null param

    The param is two elements of list for the value of null, and considered strings.

         -m:null {"" {null nil "" ~}}

  -validate

    Experiment,old: Output stream contains YAML's-tag, each node.

        % puts [::yaml::load -validate {[aaa, bbb]}]
        =>
        !!seq {{!!str aaa} {!!str bbb}}

::yaml::setOption ?options?

  Change implicit options for the library. Now, the params are the same as ::yaml::yaml2dict. Arguments of::yaml::yaml2dict is more priority than this setting.

::yaml::dict2yaml dict ?indent? ?wordwrap?
::yaml::list2yaml list ?indent? ?wordwrap?
::yaml::huddle2yaml huddle ?indent? ?wordwrap?

  Convert a dict/list/huddle object into YAML stream.

  indent

    spaces indent of each block node. currently default is 2.

  wordwrap

    word wrap for YAML stream. currently default is 40.

## EXAMPLES

An example of a yaml stream converted to Tcl. A yaml stream is returned as a single item with multiple elements.

    {
    --- !<tag:clarkevans.com,2002:invoice>
    invoice: 34843
    date   : 2001-01-23
    bill-to: &id001
        given  : Chris
        family : Dumars
        address:
            lines: |
                458 Walkman Dr.
                Suite #292
            city    : Royal Oak
            state   : MI
            postal  : 48046
    ship-to: *id001
    product:
        - sku         : BL394D
          quantity    : 4
          description : Basketball
          price       : 450.00
        - sku         : BL4438H
          quantity    : 1
          description : Super Hoop
          price       : 2392.00
    tax  : 251.42
    total: 4443.52
    comments:
        Late afternoon is best.
        Backup contact is Nancy
        Billsmer @ 338-4338.
    }
    =>
    invoice 34843 date 2001-01-23 bill-to {given Chris family Dumars address {lines {458 Walkman Dr.
    Suite #292
    } city {Royal Oak} state MI postal 48046}} ship-to {given Chris family Dumars address {lines {458 Walkman Dr.
    Suite #292
    } city {Royal Oak} state MI postal 48046}} product {{sku BL394D quantity 4 description Basketball price 450.00} {sku BL4438H quantity 1 description {Super Hoop} price 2392.00}} tax 251.42 total 4443.52 comments {Late afternoon is best. Backup contact is Nancy Billsmer @ 338-4338.}

An example of a yaml object converted to Tcl. A yaml object is returned as a multi-element list (a dict).

    {
    ---
    - [name        , hr, avg  ]
    - [Mark McGwire, 65, 0.278]
    - [Sammy Sosa  , 63, 0.288]
    -
      Mark McGwire: {hr: 65, avg: 0.278}
      Sammy Sosa: { hr: 63, avg: 0.288}
    }
    =>
    {name hr avg} {{Mark McGwire} 65 0.278} {{Sammy Sosa} 63 0.288} {{Mark McGwire} {hr 65 avg 0.278} {Sammy Sosa} {hr 63 avg 0.288}}

## LIMITATIONS

tag parser not implemented. currentry, tags are merely ignored.

Only Anchor => Aliases ordering. back alias-referring is not supported.

Too many braces, or too few braces.

Not enough character set of line feeds. Please use only "\n" as line breaks.

## Bugs, Ideas, Feedback

This document, and the package it describes, will undoubtedly contain bugs and other problems. Please report such in the category yaml of the Tcllib Trackers. Please also report any ideas for enhancements you may have for either package and/or documentation.

When proposing code changes, please provide unified diffs, i.e the output of diff -u.

Note further that attachments are strongly preferred over inlined patches. Attachments can be made by going to the Edit form of the ticket immediately after its creation, and then using the left-most button in the secondary navigation bar.

## See Also

base64, huddle, json

## Keywords

data exchange, huddle, parsing, text processing, yaml

## Copyright

Copyright © 2008 KATO Kanryu <kanryu6@users.sourceforge.net>