$child_nodes_ar ar: Array Reference
$attributes_hr hr: Hash Reference
$callback_cr cr: Code (or Callback) reference
$next_node_it it: Iterator
$report_fhi fhi: File Handle for Input *1
$summary_fho fho: File Handle for Output *1
$time_re re: Regexp
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$yesterday_dt dt: Date::Time
$website_ht ht: HTML::Template
$website_tt tt: Template Toolkit
$sessions_slct: slct: IO::Select
$www_sck sck: a socket of kinds (most likely IO::Socket)
##
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$input_buf buf: a buffer
$valid_b b: used as a boolean
$entities_cnt cnt: count, or ammount
$log_f f: a format for sprintf() or printf()
$article_id id: a unique identifier
$element_idx idx: an index
$session_ser ser: a serialized object
$long_name_out out: output value for the current subroutine
##
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$report_html html: content in html format
$report_json json: content in json format
$report_txt txt: content in plain text format
$report_yaml yaml: content in yaml format
$report_xml xml: content in xml format
##
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@nodes_s s: stack (so I should only use push, pop, and $node_s[-1] on it)
@nodes_q q: a queue (so I should only use push, shift, and $node_q[0] on it)
@nodes_out out: output value for the current subroutine