( Format

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 10.7 Formatted output
 Formatted output can be made with `format':
  -- Builtin: format (FORMAT-STRING, ...)
      Works much like the C function `printf'.  The first argument
      FORMAT-STRING can contain `%' specifications which are satisfied
      by additional arguments, and the expansion of `format' is the
      formatted string.
      The macro `format' is recognized only with parameters.
    Its use is best described by a few examples:
      define(`foo', `The brown fox jumped over the lazy dog')
      format(`The string "%s" uses %d characters', foo, len(foo))
      =>The string "The brown fox jumped over the lazy dog" uses 38 characters
      format(`%.0f', `56789.9876')
      len(format(`%-*X', `300', `1'))
    Using the `forloop' macro defined in  Loops, this example
 shows how `format' can be used to produce tabular output.
      forloop(`i', `1', `10', `format(`%6d squared is %10d
      ', i, eval(i**2))')
      =>     1 squared is          1
      =>     2 squared is          4
      =>     3 squared is          9
      =>     4 squared is         16
      =>     5 squared is         25
      =>     6 squared is         36
      =>     7 squared is         49
      =>     8 squared is         64
      =>     9 squared is         81
      =>    10 squared is        100
    The builtin `format' is modeled after the ANSI C `printf' function,
 and supports these `%' specifiers: `c', `s', `d', `o', `x', `X', `u',
 `e', `E', `f', `F', `g', `G', and `%'; it supports field widths and
 precisions, and the modifiers `+', `-', ` ', `0', `#', `h' and `l'.
 For more details on the functioning of `printf', see the C Library
    For now, unrecognized specifiers are silently ignored, but it is
 anticipated that a future release of GNU `m4' will support more
 specifiers, and give warnings when problems are encountered.  Likewise,
 escape sequences are not yet recognized.
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