Info Catalog calc: Algebraic Entry calc: Introduction calc: Prefix Arguments

calc: Quick Calculator

 
 4.6 “Quick Calculator” Mode
 ===========================
 
 There is another way to invoke the Calculator if all you need to do is
 make one or two quick calculations.  Type ‘C-x * q’ (or ‘M-x
 quick-calc’), then type any formula as an algebraic entry.  The
 Calculator will compute the result and display it in the echo area,
 without ever actually putting up a Calc window.
 
    You can use the ‘$’ character in a Quick Calculator formula to refer
 to the previous Quick Calculator result.  Older results are not
 retained; the Quick Calculator has no effect on the full Calculator’s
 stack or trail.  If you compute a result and then forget what it was,
 just run ‘C-x * q’ again and enter ‘$’ as the formula.
 
    If this is the first time you have used the Calculator in this Emacs
 session, the ‘C-x * q’ command will create the ‘*Calculator*’ buffer and
 perform all the usual initializations; it simply will refrain from
 putting that buffer up in a new window.  The Quick Calculator refers to
 the ‘*Calculator*’ buffer for all mode settings.  Thus, for example, to
 set the precision that the Quick Calculator uses, simply run the full
 Calculator momentarily and use the regular ‘p’ command.
 
    If you use ‘C-x * q’ from inside the Calculator buffer, the effect is
 the same as pressing the apostrophe key (algebraic entry).
 
    The result of a Quick calculation is placed in the Emacs “kill ring”
 as well as being displayed.  A subsequent ‘C-y’ command will yank the
 result into the editing buffer.  You can also use this to yank the
 result into the next ‘C-x * q’ input line as a more explicit alternative
 to ‘$’ notation, or to yank the result into the Calculator stack after
 typing ‘C-x * c’.
 
    If you give a prefix argument to ‘C-x * q’ or finish your formula by
 typing <LFD> (or ‘C-j’) instead of <RET>, the result is inserted
 immediately into the current buffer rather than going into the kill
 ring.
 
    Quick Calculator results are actually evaluated as if by the ‘=’ key
 (which replaces variable names by their stored values, if any).  If the
 formula you enter is an assignment to a variable using the ‘:=’
 operator, say, ‘foo := 2 + 3’ or ‘foo := foo + 1’, then the result of
 the evaluation is stored in that Calc variable.  Store and
 Recall.
 
    If the result is an integer and the current display radix is decimal,
 the number will also be displayed in hex, octal and binary formats.  If
 the integer is in the range from 1 to 126, it will also be displayed as
 an ASCII character.
 
    For example, the quoted character ‘"x"’ produces the vector result
 ‘[120]’ (because 120 is the ASCII code of the lower-case “x”; 
 Strings).  Since this is a vector, not an integer, it is displayed
 only according to the current mode settings.  But running Quick Calc
 again and entering ‘120’ will produce the result ‘120 (16#78, 8#170, x)’
 which shows the number in its decimal, hexadecimal, octal, and ASCII
 forms.
 
    Please note that the Quick Calculator is not any faster at loading or
 computing the answer than the full Calculator; the name “quick” merely
 refers to the fact that it’s much less hassle to use for small
 calculations.
 

Info Catalog calc: Algebraic Entry calc: Introduction calc: Prefix Arguments