Strings
=======

Character strings are not a special data type in the Calculator.
Rather, a string is represented simply as a vector all of whose
elements are integers in the range 0 to 255 (ASCII codes).  You can
enter a string at any time by pressing the `"' key.  Quotation marks
and backslashes are written `\"' and `\\', respectively, inside
strings.  Other notations introduced by backslashes are:

     \a     7          \^@    0
     \b     8          \^a-z  1-26
     \e     27         \^[    27
     \f     12         \^\\   28
     \n     10         \^]    29
     \r     13         \^^    30
     \t     9          \^_    31
                       \^?    127

Finally, a backslash followed by three octal digits produces any
character from its ASCII code.

Strings are normally displayed in vector-of-integers form.  The
`d "' (`calc-display-strings') command toggles a mode in
which any vectors of small integers are displayed as quoted strings
instead.

The backslash notations shown above are also used for displaying
strings.  Characters 128 and above are not translated by Calc; unless
you have an Emacs modified for 8-bit fonts, these will show up in
backslash-octal-digits notation.  For characters below 32, and for
character 127, Calc uses the backslash-letter combination if there is
one, or otherwise uses a `\^' sequence.

The only Calc feature that uses strings is "compositions";
See Compositions.  Strings also provide a convenient
way to do conversions between ASCII characters and integers.

There is a `string' function which provides a different display
format for strings.  Basically, `string(S)', where S
is a vector of integers in the proper range, is displayed as the
corresponding string of characters with no surrounding quotation
marks or other modifications.  Thus `string("ABC")' (or
`string([65 66 67])') will look like `ABC' on the stack.
This happens regardless of whether `d "' has been used.  The
only way to turn it off is to use `d U' (unformatted language
mode) which will display `string("ABC")' instead.

Control characters are displayed somewhat differently by `string'.
Characters below 32, and character 127, are shown using `^' notation
(same as shown above, but without the backslash).  The quote and
backslash characters are left alone, as are characters 128 and above.

The `bstring' function is just like `string' except that the resulting
string is breakable across multiple lines if it doesn't fit all on one
line.  Potential break points occur at every space character in the
string.