App::yamlsel - Select YAML elements using CSel (CSS-selector-like) syntax


This document describes version 0.008 of App::yamlsel (from Perl distribution App-yamlsel), released on 2020-04-29.





 yamlsel(%args) -> [status, msg, payload, meta]

Select YAML elements using CSel (CSS-selector-like) syntax.

This function is not exported.

Arguments ('*' denotes required arguments):

  • expr => str

  • file => filename (default: "-")

  • node_actions => array[str] (default: ["print_as_string"])

    Specify action(s) to perform on matching nodes.

    Each action can be one of the following:

    • count will print the number of matching nodes.

    • print_method will call on or more of the node object's methods and print the result. Example:


    • dump will show a indented text representation of the node and its descendants. Each line will print information about a single node: its class, followed by the value of one or more attributes. You can specify which attributes to use in a dot-separated syntax, e.g.:

      which will result in a node printed like this:

      HTML::Element tag=p id=undef class=undef

    By default, if no attributes are specified, id is used. If the node class does not support the attribute, or if the value of the attribute is undef, then undef is shown.

    • eval will execute Perl code for each matching node. The Perl code will be called with arguments: ($node). For convenience, $_ is also locally set to the matching node. Example in htmlsel you can add this action:

      eval:'print $_->tag'

      which will print the tag name for each matching HTML::Element node.

  • node_actions_on_descendants => str (default: "")

    Specify how descendants should be actioned upon.

    This option sets how node action is performed (See node_actions option).

    When set to '' (the default), then only matching nodes are actioned upon.

    When set to 'descendants_depth_first', then after each matching node is actioned upon by an action, the descendants of the matching node are also actioned, in depth-first order. This option is sometimes necessary e.g. when your node's as_string() method shows a node's string representation that does not include its descendants.

  • select_action => str (default: "csel")

    Specify how we should select nodes.

    The default is csel, which will select nodes from the tree using the CSel expression. Note that the root node itself is not included. For more details on CSel expression, refer to Data::CSel.

    root will return a single node which is the root node.

Returns an enveloped result (an array).

First element (status) is an integer containing HTTP status code (200 means OK, 4xx caller error, 5xx function error). Second element (msg) is a string containing error message, or 'OK' if status is 200. Third element (payload) is optional, the actual result. Fourth element (meta) is called result metadata and is optional, a hash that contains extra information.

Return value: (any)


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