Wikiup:Lua/Modul/Expr/en

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Expr – Module with functions for any kind of expression in addition to the functionality offered by #expr parser functions.

The results of those Lua functions are supposed to be used within other computations or conditions. Therefore they need to be numbers rather than text and leave no way to communicate any error message nor triggering a maintenance category.

Functions for templates

The standard functions are supposed to be used in #invoke and retrieve those parameters. Whitespace ahead and after any content is ignored.

average

Calculate average

• 1 – First number
• 2 – Second number
• parse – (optional) number format in transclusions
• 3 – (optional) Further number
• 4 usw. – (optional) Further numbers, as many as desired

The average is always at least 0 and invalid values will be ignored.

base62

Coding und decoding according to Base62.

• 1 – figure to be converted
• 2 – (optional) D2B for decimal-into-base62; default: base62-into-decimal

crossTotal

Calculate sum of digits

• 1 – positive number, digits only (minus sign and decimal fraction would be ignored)

Yields at least 0.

decimal2minsec

Coordinate value conversion from decimal to degrees / minutes / seconds

• 1 – decimal value
• 2 – (optional) number of fractional digits after separator in seconds (default: none)
• parse – (optional) number format of decimal value

Yields non-breaking <span> element with degrees / minutes / seconds, else 0

figure

Test figure for validity and convert if possible

• 1 – number
• 2 – (optional) number format

Yields nothing if invalid.

max

Retrieve maximum of a set of figures.

All unnamed parameters are used for extremum calculation.

• Parameter values may be empty or can contain expressions, which can be evaluated by #expr parser function.
• Both ASCII minus U+002D and U+2212 − are accepted.
• Options are available as named parameters:
  • minus – minus sign coding in result; see below
  • zeroBlank=1 – present zero as empty value

The return value is an empty string (nothing), if no parameter at all or only empty values were provided. An error message for invalid #expr might occur as well. Otherwise that is the determined number in the specified formatting.

min

Retrieve minimum in the same way as max.

minsec2decimal

Coordinate value conversion from degrees / minutes / seconds to decimal number

• 1 – degrees
• 2 – (optional) minutes
• 3 – (optional) seconds
• 4 – (optional) lettter for compass direction
• parse – (optional) number format in transclusions

modulo

Modulo, remainder

• 1 – current value (dividend)
• 2 – unit value (base, divisor) non-zero
• parse – (optional) number format in transclusions

percent

Retrieve percentage

• 1 – part
• 2 – base value (related unit, 100 %) non-zero
• 3 – (optional) number of fractional digits after separator (default: none)
• 4 – (optional) keep trailing zeros in fractional digits
• parse – (optional) number format in transclusions
• low – (optional) result format, 1 for “computer interface” (default: local Wiki).

The result ist terminated by % and therfore the number is no longer subject to formatting.

Ramanujan

random

(Pseudo-) random number (integer)

• 1 – (optional) base, standardization, number of values (default: 100), integer >1.

Results in integer numbers beginning at (including) zero, therefore always less than number of values.

Each transclusion in page yields an independent and mostly different result.

seed numbers for ensuring different values in page are not necessary.

sum

Calculate sum

• 1 – First number
• 2 – Second number
• parse – (optional) number format in transclusions
• 3 – (optional) Further number
• 4 usw. – (optional) Further numbers, as many as desired

The sum is always at least 0 and invalid values will be ignored.

failsafe

Version management

{{Wikipedia:Lua/Modul-Failsafe/en|Modul=Expr}}

Direct transclusion in templates

TemplateAverage

Like average, but use all parameters of the template around.

TemplateBooland

Yields 1, if all parameters are “something”, else “nothing”.

Use parameters of the template around.

TemplateBoolor

Yields 1, if at least one parameter is “something”, else “nothing”.

Use parameters of the template around.

TemplateMax

Like max, but specific to Template:Max – use all parameters of the template around.

TemplateMin

Like min, but specific to Template:Min – use all parameters of the template around.

TemplateSum

Like sum, but use all parameters of the template around.

Unicode minus

The minus sign is treated as follows:

• On input values they may be used at will.
• If any input value contains a Unicode minus U+2212, this encoding will be used in the result.
• Optional minus=1
  Use Unicode minus only for resulting string.
• Optional minus=-
  Use ASCII hyphen only for resulting string.

A result with Unicode minus is by nature always a string.

Number format in transclusions

An optional parameter permits variable interpretation of input values.

• The default is . with the meaning “computer calculation format”.
• The meaning of “computer calculation format” is: . as decimal separator, minus sign in ASCII, no grouping (thousands). Alternatively the E exponential representation may be used.

The supported input format, if provided, consists of one til three codes mgd with the components:

• d – mandatory if used: decimal separator. Permitted values: . or , (only at last position).
• m – minus sign may be used as “typographic” (Unicode U+2212) when - (only at first position).
• g – number grouping (thousands), even following decimal separator, permitted according to subsequent table(optional).

Codes for number grouping

g	Meaning
,	comma, used in angloamerican formatting
.	period; default formatting in German Wikipedia
'	ASCII apostrophe; common in Switzerland
',	ASCII apostrophe or comma
'.	ASCII apostrophe or period
U+20	ASCII space Not recommended as number format, but may be used for analysis.
U+A0	non-breaking space
U+202F	narrow non-breaking space
%s	ASCII or (even narrow) non-breaking space
.%s	period or ASCII space or (even narrow) non-breaking space
'%s	ASCII apostrophe or ASCII space or (even narrow) non-breaking space
'.%s	period or ASCII apostrophe or ASCII space or (even narrow) non-breaking space

On input HTML entities may be used alternatively for number grouping.

• “Scientific” or exponential representation does require always “computer calculation format”: e oder E, integer exponent, + may precede mantissa and/or exponent.

Examples:

• ,. – classical angloamerican format (ASCII)
• -'.%s, – broadest acceptance of German formats, typographic minus possible

Examples (test page)

A test page illustrates practical use.

Functions for Lua modules (API)

All functions documented above may be used via require() in other Modules:

local lucky, Expr = pcall( require, "Module:Expr" )
if type( Expr ) == "table" then
    Expr = Expr()
else
    -- Error; Expr contains error message
    return "<span class='error'>" .. Expr .. "</span>"
end

Then there is available:

Expr.average( array, ask )

• array – sequence table, with string or number items
• ask – number format of input

returns: number, at least 0

Expr.base62( adjust )

• adjust – string or number
  • number – code in base62 (string)
  • string – dekcode in number

Expr.crossTotal( amount )

• amount – string or number

returns: number, sum of digits in integer number, at least 0

Expr.decimal2minsec( amount, align, ask )

• amount – decimal coordinate, string or number
• align – number of decimal digits of seconds, string or number (default: 0)
• ask – number format of decimal number

returns: mw.html object if success, else string 0

Expr.figure( amount, ask )

• amount – number, string or number
• ask – number format

returns: number, or false if invalid

Expr.minsec2decimal( aDeg, aMin, aSec, alter, ask )

• aDeg – degree, string or number
• aMin – minutes, string or number or nothing
• aSec – seconds, string or number or nothing
• alter – letter for compass direction, like S or W, or nothing
• ask – number format of input

returns: number, 0 if invalid

Expr.modulo( amount, adjust, ask )

• amount – figure, string or number
• adjust – base, string or number
• ask – number format of input

returns: number, 0 if invalid

Expr.percent( amount, all, align, after, ask, allow, frame )

• amount – part, string or number
• adjust – base, string or number
• align – number of fractional digits after separator, string or number (default: none)
• after – true, to keep trailing zeros in fractional digits
• ask – number format of input
• allow – result format, true, for „computational format“ (default: local Wiki).
• frame – object, if available

The result is terminated by % and the number itself is not accessible for formatting.

• number 0 if invalid

Expr.sum( array, ask )

• array – sequence table, with string or number items
• ask – number format of input

Two results:

1. number, with sum, at least 0
2. number, of valid summands, at least 0

Expr.failsafe( atleast )

(like template)

Usage

General library; no limitations.

Dependencies

None.