This library provides writef/1 and friends. These predicates originate
from Edinburgh C-Prolog and and provided for compatibility purposes. New
code should use format/1, format/2 and friends, which are currently
supported by more Prolog implementations.
The writef-family of predicates conflicts with the modern
character-esacapes flag about the interpretation of \-sequences.
This can be avoided by
- Disable character escapes (not recommended unless one wants to
run really outdated code unmodified).
- Double the \ for conflicting interpretations
- Use ISO compliant alternatives for conflicting interpretations
- - Copied from Edinburgh C-Prolog. Original version by Byrd,
changed many times since.
- writef(+Format) is det
- writef(+Format, +Arguments) is det
- Formatted write to the
current_output. Format is a format
specifier. Some escape sequences require arguments that must be
provided in the list Arguments. There are two types of escape
sequences: special characters start with
\ and include
arguments start with
%. The special character sequences are:
|Output a newline character|
|Output a line separator (same as |
|Output a carriage-return character (ASCII 13)|
|Output a TAB character (ASCII 9)|
|Output character <nnn>. <nnn> is a 1-3 decimal number|
Escape sequences to include arguments from Arguments. Each time
a %-escape sequence is found in Format the next argument from
Arguments is formatted according to the specification.
|print/1 the next item (mnemonic: term)|
|write/1 the next item|
|writeq/1 the next item|
|display/1 the next item|
|Put the next item as a character|
|Write the next item N times where N is the second item (an integer)|
|Write the next item as a String (so it must be a list of characters)|
|Perform a ttyflush/0 (no items used)|
|Write the next item Centered in N columns.|
|Write the next item Left justified in N columns.|
|Write the next item Right justified in N columns.|
- - New code should use format/1, format/2, etc.
- swritef(-String, +Format) is det
- swritef(-String, +Format, +Arguments) is det
- Use writef/1 or writef/2 and write the result to a string.
Note that this is a string in the sense of string_codes/2,
not a list of
- - . See format/2,3 and/or with_output_to/2.