The ParserFunctions extension adds even more parser functions to the magic words allowed on the Scratch Wiki. The syntax of parser functions are: {{#functionname:argument 1|argument 2|argument 3 ...}}}.

#expr

Main page: Help:Calculation

The #expr (expression) function evaluates expressions in the function. The syntax of this function goes: {{#expr|expression}}. Expressions are placed in the expression parameter and the function will be replaced with an answer. The expressed answer can be an error message, if the calculation cannot be done. Boolean/logical truth gates considers all numbers except zero to be true, and zero to be false. Empty expressions yield empty answers.

Code Output Explanation
{{#expr:5+5}} 10 Five plus five is equal to ten.
{{#expr:8/0}} Division by zero. Any division by zero is undefined, therefore, no answer.
{{#expr: }} Empty spaces result in no output.
{{#expr:5 and 0}} 0 5 is True, while 0 is False, so they don't both equal true. The expression is false, represented by a zero.

#if

This function evaluates a text field to determine whether it is empty or not. If it is empty, it will print out a value. If not, it will print out another value. The values are user-defined. White space is considered an empty string. All text in the function is parsed as plain text. The syntax of this function goes: {{#if:string|value returned if string is not empty|value returned if string is empty}}.

Code Output Explanation
{{#if: |true|false}} false The text field is empty (only spaces), so the expression is false.
{{#if:notblank|true|false}} true The text field is not empty, so the expression is true.
{{#if:a b|true|false}} true The text field is not empty (has text in it), so the expression is true.

#ifeq

This function (if equal) evaluates two strings and checks to see if they are equal. The syntax of this function goes: {{#ifeq:string|string2|value returned if equal|value returned if not equal}}. Avoid putting html tags into the text filed; parser tags are replaced, and will not equal each other. Numerical answer and string answers are parsed differently; numerical values are compared numerically (01 is the same as 1) and string functions are placed in quotations and are case-sensitive and numbers are parsed as text, therefore 01 and 1 are not equal. In this function, all numbers are turned into type integer, so the digit accuracy goes up to 9E18.

Code Output Explanation
{{#ifeq: 0| 0 |true|false}} true Numerical values are treated as numbers, so spaces do not matter.
{{#ifeq: "0 "|" 0 "|true|false}} false Spaces in strings count. Since the spaces are not equal with each other, the expression is false.
{{#ifeq: nien ma|nienma|true|false}} false All strings, in or not in quotations, are treated as text and spaces count.
{{#ifeq: J|j|true|false}} false Strings are case-sensitive.

#iferror

Functions such as the #expr function, have errors messages in case something goes wrong. This function checks to see if a nested function has outputted an error message or not. The syntax of this function goes: {{#iferror:input|string if error message is found|string if error message is not found}}. A combination of parameters are optional. If the 'string if error message is not found' parameter is omitted, then an error-free output will then be displayed. If you remove both 'string if error message is not found' and 'string if error message is found' parameters, then an error will be shown as a blank string.

Code Output Explanation
{{#iferror: {{#expr:5+5}} |er|no er}} no er 5+5 is a valid expression, and no errors were produced, so 'no er(rors)' is printed.
{{#iferror: {{#expr:abc}} |er|no er}} er abc is not a valid mathematical expression to solve. er(rors) is displayed.
{{#iferror: {{#expr:2/8}} |er}} 0.25 2/8 is a valid expression. Since there is no 'no er(ror)' parameter, the expression answer is displayed.
{{#iferror: {{#expr:@#$^&*}} |er}} er @#$^&* is not a valid mathematic expression. Therefore, er(ror) is displayed.
{{#iferror: {{#expr:2^3}}}} 8 2^3 is a good expression. Since there is no 'no er(ror)' parameter, the expression answer is displayed.
{{#iferror: {{#expr:=}} }} = is not a good expression. Since there is no 'no er(ror)' or a 'er(ror)' parameter, nothing is outputted.
{{#iferror:<span class="error">a</span>|er|no er}} er This function detects any error classes. The class "error" is one, so the function shows its output as 'er(ror)'.

#ifexpr

This function (if expression [is true/false]) evaluates an expression then returns one of the two parameters. The syntax of this function goes: {{#ifexpr:expression|string if true|string if false}}. The expression is parsed exactly the way #expr is, and a blank expression results in 'false'. In any case, all numbers are equal to true, except zero which is equal to false in boolean calculations. The 'false' parameter can be omitted; if an expression is false, the output shows a blank space. The "true" parameter can also be omitted, but the pipe characters still needs to be placed.

Code Output Explanation
{{#ifexpr: |true|false}} false Empty expressions are considered false.
{{#ifexpr: 8>9 |true|false}} false Eight is not greater than nine, so the output is false.
{{#ifexpr: = |true|false}} Expression error: Unexpected = operator. Since = is an inaccurate expression, an error shows up.
{{#ifexpr: 8+4^5 |true|false}} true Since there is no comparison, the value is always true.
{{#ifexpr: 8=9 |true}} Since 8=9 is false, and there is no 'false' parameter, an empty output shows.
{{#ifexpr: (3+3) = (2+4) ||false}} Since 3+3 = 2+4 is true, and there is an empty 'true' parameter, an empty output shows.
{{#ifexpr: 9>=9}} Since 9>=9 is true, and there are no parameters, an empty output shows.

#ifexist

This expensive function takes a string, interprets it as a page title and returns one of two values depending on whether the page exists or not. The syntax of this function goes: {{#ifexist:page title|string if exists|string if doesn't exist}}. There is a 100 call limit on this function.

Code Output Explanation
{{#ifexist: Help:ParserFunctions|exists|does not exist}} exist This page exists.
{{#ifexist: Scratch Wiki:ParserFunctions|exists|does not exist}} does not exists The namespace matters.

#rel2abs

The function turns relative file paths into absolute file paths, as the name suggests ("relative to absolute"). The first parameter is the path, and the second parameter is the base path. The base path is optional - if left nil, the full name of the current page is used. The path parameter accepts the following syntax:

  • . — the current level
  • .. — go up one level
  • /x — go down one level into the subdirectory x
Code Output Explanation
{{#rel2abs:/abc|Scratch Wiki:Example}} Scratch Wiki:Example/abc The path is appended onto the base path.
{{#rel2abs:../../ms|Scratch Wiki:Example/Example2/Example3}} Scratch Wiki:Example/ms Two level up from the base path is Scratch Wiki:Example, then append path ms.
{{#rel2abs:../ms|Scratch Wiki:Example}} ms One level up from the base path nil, then appends ms without leading / because the path is added to a nil path.
{{#rel2abs:../.|Scratch Wiki:Example/Example2}} Scratch Wiki:Example Goes one level up, then gets the current level (equivalent to {{#rel2abs:..|Scratch Wiki:Example/Example2}})
{{#rel2abs:../../..|Scratch Wiki:Example/Example2}} Error: Invalid depth in path: "Scratch Wiki:Example/Example2/../../.." (tried to access a node above the root node). Goes three level up, which does not exist.

#switch

This function compares a comparison with several cases, and outputs a string defined in each case. This function is equivalent to:

set [comparison v] to [hello]
set [output v] to []
if <(comparison) = [hello]> then //case1
set [output v] to [welcome!]
else
if <(comparison) = [bye]> then //case2
set [output v] to [see you!]
else
set [output v] to [ok!] //default case
end
end

In this case, the output variable returns "welcome!". Be aware, this function is case-sensitive.

Code Output Explanation
{{#switch:pop|lol = HI|pop = BOOM|aww :(}} BOOM pop, the argument, matches case 2, |pop = BOOM|, and prints BOOM.
{{#switch:dfd|lol = HI|pop = BOOM|aww :(}} aww :( dfd, the argument, matches no case, and prints the default case, aww :(.
{{#switch:A|a = lowercase a|none of the above}} none of the above This function is case-sensitive.
{{#switch:ps|lf = le}} If the condition matches no case and a default case is not given, the output is null.

#time

This function formats a given date into a specified format.
{{#time: format | date given (default is {{CURRENTTIMESTAMP}}) | language code}}. The table below gives some of the main format codes that can be used. Careful, the format code is case sensitive.

Note Note: The time outputted by default is only accurate in the UTC time zone. Use the date given parameter to adjust the hour to one's own time zone.
Format codes
Code Description Output
Y Full year 2018
y 2-digit year 18
L Leap-year indicator, is one if it is a leap year, otherwise 0. 0
n Month not padded 12
m Month padded 12
M Month abbreviated Dec
F Full name of month December
W Week, padded 50
j Day of the month, not padded 11
d Day of the month, padded 11
z Day of the year 344
D Day of the week name abbreviated Tue
l Full name of day of the week Tuesday
N Day of the week (Sunday = 7) 2
w Day of the week (Sunday = 0) 2
a AM or PM am
g Hour in 12-hour format, not padded 11
h Hour in 12-hour format, padded 11
G Hour in 24-hour format, not padded 11
H Hour in 24-hour format, padded 11
i Minutes past hour, padded 14
s Seconds past hour, padded 55
t Days in the month 31

We can place strings into the format code as well.

Code Output Explanation
{{#time:d-m-Y, G:i|now+2 hours}} 11-12-2018, 13:14 The format string is day padded "-" month padded "-" 4-digit year "," 24-hour format hour ":" minutes past hour. The date provided is the current timestamp plus two hours.
{{#time:d-"m"-Y}} 11-m-2018 To literally show format code letters, use quotations.
{{#time:M||de}} Dez. "de", or the character code for German, is places as the language code to translate the months.

#timel

This is exactly the same as #time, but uses the wiki local time taken from $wgLocaltimezone.
{{#timel: format | date given (default is {{CURRENTTIMESTAMP}}) | language code}}

#titleparts

The function splits a page title by its slashes and sub-pages. This function can accept three arguments, pagename, optional number of segments, and optional first segment. If the number of segments parameter is omitted, then it defaults to "0", returning all segments. If the first segment parameter is omitted, it defaults to one.

Code Output Explanation
{{#titleparts:Talk:Hello/Bye/Yo/Me/See|1|2}} Bye Goes to the first section ("Bye") and returns only itself.
{{#titleparts:Talk:Hello/Bye/Yo/Me/See||3}} Yo/Me/See The number of segments parameter is omitted, which means that it defaults to 0 (returns all the segments). The start is 3 (at "Yo"), so it returns everything starting at "Yo".
{{#titleparts:Talk:Hello/Bye/Yo/Me/See||-2}} Me/See Returns the last two segments.
{{#titleparts:Talk:Hello/Bye/Yo/Me/See|-2}} Talk:Hello/Bye/Yo Removes 2 segments from the end of the string.
{{#titleparts:Talk:Hello/Bye/Yo/Me/See|-2|-3}} Yo Removes 2 segments from the end of the string then starts from the 3rd last segment.

See Also