Editing Module:Arguments/doc (section)

=== Frames and parent frames ===

Arguments in the <code>args</code> table can be passed from the current frame or from its parent frame at the same time. To understand what this means, it is easiest to give an example. Let's say that we have a module called <code>Module:ExampleArgs</code>. This module prints the first two positional arguments that it is passed.

{{cot|Module:ExampleArgs code}}
<syntaxhighlight lang="lua">
local getArgs = require('Module:Arguments').getArgs
local p = {}

function p.main(frame)
	local args = getArgs(frame)
	return p._main(args)
end

function p._main(args)
	local first = args[1] or ''
	local second = args[2] or ''
	return first .. ' ' .. second
end

return p
</syntaxhighlight>
{{cob}}

<code>Module:ExampleArgs</code> is then called by <code>Template:ExampleArgs</code>, which contains the code <code><nowiki>{{#invoke:ExampleArgs|main|firstInvokeArg}}</nowiki></code>. This produces the result "firstInvokeArg".

Now if we were to call <code>Template:ExampleArgs</code>, the following would happen:

{| class="wikitable" style="width: 50em; max-width: 100%;"
|-
! style="width: 60%;" | Code
! style="width: 40%;" | Result
|-
| <code><nowiki>{{ExampleArgs}}</nowiki></code>
| firstInvokeArg
|-
| <code><nowiki>{{ExampleArgs|firstTemplateArg}}</nowiki></code>
| firstInvokeArg
|-
| <code><nowiki>{{ExampleArgs|firstTemplateArg|secondTemplateArg}}</nowiki></code>
| firstInvokeArg secondTemplateArg
|}

There are three options you can set to change this behaviour: <code>frameOnly</code>, <code>parentOnly</code> and <code>parentFirst</code>. If you set <code>frameOnly</code> then only arguments passed from the current frame will be accepted; if you set <code>parentOnly</code> then only arguments passed from the parent frame will be accepted; and if you set <code>parentFirst</code> then arguments will be passed from both the current and parent frames, but the parent frame will have priority over the current frame. Here are the results in terms of <code>Template:ExampleArgs</code>:

; frameOnly
{| class="wikitable" style="width: 50em; max-width: 100%;"
|-
! style="width: 60%;" | Code
! style="width: 40%;" | Result
|-
| <code><nowiki>{{ExampleArgs}}</nowiki></code>
| firstInvokeArg
|-
| <code><nowiki>{{ExampleArgs|firstTemplateArg}}</nowiki></code>
| firstInvokeArg
|-
| <code><nowiki>{{ExampleArgs|firstTemplateArg|secondTemplateArg}}</nowiki></code>
| firstInvokeArg
|}

; parentOnly
{| class="wikitable" style="width: 50em; max-width: 100%;"
|-
! style="width: 60%;" | Code
! style="width: 40%;" | Result
|-
| <code><nowiki>{{ExampleArgs}}</nowiki></code>
| 
|-
| <code><nowiki>{{ExampleArgs|firstTemplateArg}}</nowiki></code>
| firstTemplateArg
|-
| <code><nowiki>{{ExampleArgs|firstTemplateArg|secondTemplateArg}}</nowiki></code>
| firstTemplateArg secondTemplateArg
|}

; parentFirst
{| class="wikitable" style="width: 50em; max-width: 100%;"
|-
! style="width: 60%;" | Code
! style="width: 40%;" | Result
|-
| <code><nowiki>{{ExampleArgs}}</nowiki></code>
| firstInvokeArg
|-
| <code><nowiki>{{ExampleArgs|firstTemplateArg}}</nowiki></code>
| firstTemplateArg
|-
| <code><nowiki>{{ExampleArgs|firstTemplateArg|secondTemplateArg}}</nowiki></code>
| firstTemplateArg secondTemplateArg
|}

Notes:
# If you set both the <code>frameOnly</code> and <code>parentOnly</code> options, the module won't fetch any arguments at all from #invoke. This is probably not what you want.
# In some situations a parent frame may not be available, e.g. if getArgs is passed the parent frame rather than the current frame. In this case, only the frame arguments will be used (unless parentOnly is set, in which case no arguments will be used) and the <code>parentFirst</code> and <code>frameOnly</code> options will have no effect.