24
Picture Clause Specification
This reference describes picture clauses and the syntax used to express them. It provides guidance to
template designers who wish to create picture clauses that specify the format of dates, times, numbers
and text. Such picture clauses are used in the following contexts:
●
Data output formatting and input parsing, as described in
“Localization and Canonicalization” on
Data conversion performed by some FormCalc functions, as described in
“FormCalc Specification” on
●
About
Picture clauses
are a sequence of symbols (characters) that specify the rules for formatting and parsing
textual data, such as dates, times, numbers and text. Each
symbol
is a place-holder that typically represents
one or more characters that occur in the data. FormCalc supports the BMP characters described in
[Unicode-2.1].Often
the terms
pattern
and
picture format
are used as synonyms for the term
picture clause.
A picture clause can be used equally for output formatting of data and input parsing of data.
Output
formatting
is the process of transforming a raw value into a formatted value, under the direction of a
picture clause.
Input parsing
is the process of transforming a formatted input value into a raw elemental
value, again under the direction of a picture clause. The raw elemental values that result from input
parsing are represented in the canonical formats described in
“Canonical Format Reference” on page 797.
Picture clauses can passively use the template-declared locale or the ambient locale, or they can specify a
particular locale (language alone or a country and language). Additionally, date and time picture clauses
can specify certain characteristics used in East Asian locales, including ideographs and full-width
characters, Asian numeric system, era years, and era styles. (“Asian
Considerations” on page 910)
How Picture Clauses Are Used
Picture clauses are used as properties in XFA templates and as arguments in FormCalc, as described in the
“FormCalc Specification” on page 801.
An XFA processing application uses the picture clause properties to
determine how to perform localized output formatting and input parsing, as described in
“Localization
and Canonicalization” on page 140.
The following table summarizes the role of picture clauses in FormCalc functions.
Picture clause
parent element
Output
Input
(Alternate name)
formatting parsing
format()
parse()
✔
✔
Role of picture clause
Specifies the formatting to be applied to a date, which is
supplied in canonical format
Specifies the formatting expected in a date
901