data/format
(format out str &args)
Macro defined at lib/data/format.lisp:117:2
Output the string STR formatted against ARGS to the stream OUT. In
the case OUT is nil, a string in returned; If OUT is true, the result
is printed to standard output.
Formatting specifiers
Formatting specifiers take the form {...}, where ... includes
both a reference (what’s to be output) and a formatter (how to
output it).
- If the reference starts with
#, it is an implicit named symbol
(something in scope, and not passed explicitly).
- If the reference starts with an alphabetic character, it is
named: something given to the
format macro explicitly, as a
keyword argument.
- If the reference starts with
$, it is a positional argument.
The formatter can either start with :, in which case it references
an Urn symbol, or start with %, in which case it is a string.format
format sequence.
Examples
> (format nil "{#pretty:pretty} is {what}" :what 'pretty)
out = "«method: (pretty x)» is pretty"
> (format nil "0x{foo%x}" :foo 123)
out = "0x7b"