W3TPL/tag/get-let

About

The <get> and <let> tags are very similar, and can do similar things, even though in a way they are opposite operations.

• get:
  • retrieves an input or stored value and (ultimately) outputs it to the display.
    • The result is always displayed (though this can be captured and/or hidden by enclosure within another tag).
  • does not require a name= attribute.
  • is like <let> with echo and self assumed, except it doesn't store the result.
• let:
  • receives an input value and (ultimately) stores it as a variable.
    • The result is always stored in a variable (though it can also be displayed with echo).
  • requires a name= attribute.
  • if echo and self are used, is like <get> except it stores the result in a named variable.

Attributes

Each attribute is processed within a given stage, where stages are processed in essentially this order:

• GetTagInput():
  • (input) = input stage (determining where the input value should come from, and retrieving it)
• UseTagInput():
  • (calc) = doing things with the retrieved input. The output of each operation becomes the input for the next.
    • Note that we can't really count on MediaWiki's parser preserving the order of attributes within a tag, however.
  • (output): = putting the results other places besides the target variable

The following attributes are common to both get and let:

• append (calc): append the input string to the current value
• arg= (input): name of $wgRequest (POST or GET) field to retrieve as tag input
  • USAGE: form processing
• chr= (input): ASCII number of character to use as tag input
• copy= (input): name of another variable whose value should become the input
• lcase (calc): apply strtolower(), i.e. convert the input to lower case
  • opposite of "ucase"
• lcfirst (calc): apply lcfirst(), i.e. convert the first character of the input to lower case
  • opposite of "ucfirst"
• len= (calc): use only the first <len> characters of the input (this could probably stand some rethinking)
• newline (calc): appends a newline ("\n" in PHP) to the string (FUTURE: some way to prepend it; some way to prepend/append other short strings)
• parse (calc): have MediaWiki parse the input, and use the resulting string
• pre (calc): alias for "parse", for backwards compatibility
• trim (calc): apply trim()
• ucase (calc): apply strtoupper(), i.e. convert the input to upper case
  • opposite of "lcase"
• ucfirst (calc): apply ucfirst(), i.e. convert the first character of the input to upper case
  • opposite of "lcfirst"
• val= (input): value/expression to use as input; can be sysdata.

History

• 2022-04-20 moved common attributes from c_let to caTag_Var, so <get> and <let> can share the same processing code.
  • Have not yet updated get to use this, though.
• 2022-04-24 <get> now uses caTag_Var too