It is sometimes useful to obtain very specific information about a
locale such as the word it uses for days or months, its format for
representing floating-point figures, etc. The (ice-9 i18n)
module provides support for this in a way that is similar to the libc
functions nl_langinfo () and localeconv ()
(see accessing locale information from C in The GNU C Library Reference Manual). The available functions
are listed below.
Return the name of the encoding (a string whose interpretation is system-dependent) of either locale or the current locale.
The following functions deal with dates and times.
Return the word (a string) used in either locale or the current
locale to name the day (or month) denoted by day (or
month), an integer between 1 and 7 (or 1 and 12). The
-short variants provide an abbreviation instead of a full name.
Return a (potentially empty) string that is used to denote ante meridiem (or post meridiem) hours in 12-hour format.
These procedures return format strings suitable to strftime
(see Time) that may be used to display (part of) a date/time
according to certain constraints and to the conventions of either
locale or the current locale (see the nl_langinfo () items in The GNU C Library Reference
Manual).
These functions return, respectively, the era and the year of the relevant era used in locale or the current locale. Most locales do not define this value. In this case, the empty string is returned. An example of a locale that does define this value is the Japanese one.
The following procedures give information about number representation.
These functions return a string denoting the representation of the decimal point or that of the thousand separator (respectively) for either locale or the current locale.
Return a (potentially circular) list of integers denoting how digits of the integer part of a number are to be grouped, starting at the decimal point and going to the left. The list contains integers indicating the size of the successive groups, from right to left. If the list is non-circular, then no grouping occurs for digits beyond the last group.
For instance, if the returned list is a circular list that contains
only 3 and the thousand separator is "," (as is the case
with English locales), then the number 12345678 should be
printed 12,345,678.
The following procedures deal with the representation of monetary amounts. Some of them take an additional intl? argument (a boolean) that tells whether the international or local monetary conventions for the given locale are to be used.
These are the monetary counterparts of the above procedures. These procedures apply to monetary amounts.
Return the currency symbol (a string) of either locale or the current locale.
The following example illustrates the difference between the local and international monetary formats:
(define us (make-locale LC_MONETARY "en_US")) (locale-currency-symbol #f us) ⇒ "-$" (locale-currency-symbol #t us) ⇒ "USD "
Return the number of fractional digits to be used when printing
monetary amounts according to either locale or the current
locale. If the locale does not specify it, then #f is
returned.
These procedures return a boolean indicating whether the currency symbol should precede a positive/negative number, and whether a whitespace should be inserted between the currency symbol and a positive/negative amount.
Return a string denoting the positive (respectively negative) sign that should be used when printing a monetary amount.
These functions return a symbol telling where a sign of a positive/negative monetary amount is to appear when printing it. The possible values are:
parenthesizeThe currency symbol and quantity should be surrounded by parentheses.
sign-beforePrint the sign string before the quantity and currency symbol.
sign-afterPrint the sign string after the quantity and currency symbol.
sign-before-currency-symbolPrint the sign string right before the currency symbol.
sign-after-currency-symbolPrint the sign string right after the currency symbol.
unspecifiedUnspecified. We recommend you print the sign after the currency symbol.
Finally, the two following procedures may be helpful when programming user interfaces:
Return a string that can be used as a regular expression to recognize
a positive (respectively, negative) response to a yes/no question.
For the C locale, the default values are typically "^[yY]" and
"^[nN]", respectively.
Here is an example:
(use-modules (ice-9 rdelim))
(format #t "Does Guile rock?~%")
(let lp ((answer (read-line)))
(cond ((string-match (locale-yes-regexp) answer)
(format #t "High fives!~%"))
((string-match (locale-no-regexp) answer)
(format #t "How about now? Does it rock yet?~%")
(lp (read-line)))
(else
(format #t "What do you mean?~%")
(lp (read-line)))))
For an internationalized yes/no string output, gettext should
be used (see Gettext Support).
Example uses of some of these functions are the implementation of the
number->locale-string and monetary-amount->locale-string
procedures (see Number Input and Output), as well as that the
SRFI-19 date and time conversion to/from strings (see SRFI-19 - Time/Date Library).