The functions described here perform various operations on the Calc stack and trail. They are to be used in interactive Calc commands.
Push the Calc objects in list vals onto the stack at stack level n. If n is omitted it defaults to 1, so that the elements are pushed at the top of the stack. If n is greater than 1, the elements will be inserted into the stack so that the last element will end up at level n, the next-to-last at level n+1, etc. The elements of vals are assumed to be valid Calc objects, and are not evaluated, rounded, or renormalized in any way. If vals is an empty list, nothing happens.
The stack elements are pushed without any sub-formula selections.
You can give an optional third argument to this function, which must
be a list the same size as vals of selections. Each selection
must be eq to some sub-formula of the corresponding formula
in vals, or nil if that formula should have no selection.
Return a list of the n objects starting at level m of the stack. If m is omitted it defaults to 1, so that the elements are taken from the top of the stack. If n is omitted, it also defaults to 1, so that the top stack element (in the form of a one-element list) is returned. If m is greater than 1, the mth stack element will be at the end of the list, the m+1st element will be next-to-last, etc. If n or m are out of range, the command is aborted with a suitable error message. If n is zero, the function returns an empty list. The stack elements are not evaluated, rounded, or renormalized.
If any stack elements contain selections, and selections have not
been disabled by the j e (calc-enable-selections) command,
this function returns the selected portions rather than the entire
stack elements. It can be given a third “selection-mode” argument
which selects other behaviors. If it is the symbol t, then
a selection in any of the requested stack elements produces an
“invalid operation on selections” error. If it is the symbol full,
the whole stack entry is always returned regardless of selections.
If it is the symbol sel, the selected portion is always returned,
or nil if there is no selection. (This mode ignores the j e
command.) If the symbol is entry, the complete stack entry in
list form is returned; the first element of this list will be the whole
formula, and the third element will be the selection (or nil).
Remove the specified elements from the stack. The parameters n
and m are defined the same as for calc-top-list. The return
value of calc-pop-stack is uninteresting.
If there are any selected sub-formulas among the popped elements, and
j e has not been used to disable selections, this produces an
error without changing the stack. If you supply an optional third
argument of t, the stack elements are popped even if they
contain selections.
This function records one or more results in the trail. The vals are a list of strings or Calc objects. The tag is the four-character tag string to identify the values. If tag is omitted, a blank tag will be used.
This function takes a Calc object and “normalizes” it. At the very least this involves re-rounding floating-point values according to the current precision and other similar jobs. Also, unless the user has selected No-Simplify mode (see Simplification Modes), this involves actually evaluating a formula object by executing the function calls it contains, and possibly also doing algebraic simplification, etc.
This function is identical to calc-top-list, except that it calls
calc-normalize on the values that it takes from the stack. They
are also passed through check-complete, so that incomplete
objects will be rejected with an error message. All computational
commands should use this in preference to calc-top-list; the only
standard Calc commands that operate on the stack without normalizing
are stack management commands like calc-enter and calc-roll-up.
This function accepts the same optional selection-mode argument as
calc-top-list.
This function is a convenient form of calc-top-list-n in which only
a single element of the stack is taken and returned, rather than a list
of elements. This also accepts an optional selection-mode argument.
This function is a convenient interface to most of the above functions.
The vals argument should be either a single Calc object, or a list
of Calc objects; the object or objects are normalized, and the top n
stack entries are replaced by the normalized objects. If tag is
non-nil, the normalized objects are also recorded in the trail.
A typical stack-based computational command would take the form,
(calc-enter-result n tag (cons 'calcFunc-func
(calc-top-list-n n)))
If any of the n stack elements replaced contain sub-formula
selections, and selections have not been disabled by j e,
this function takes one of two courses of action. If n is
equal to the number of elements in vals, then each element of
vals is spliced into the corresponding selection; this is what
happens when you use the TAB key, or when you use a unary
arithmetic operation like sqrt. If vals has only one
element but n is greater than one, there must be only one
selection among the top n stack elements; the element from
vals is spliced into that selection. This is what happens when
you use a binary arithmetic operation like +. Any other
combination of n and vals is an error when selections
are present.
This function implements a unary operator that allows a numeric prefix
argument to apply the operator over many stack entries. If the prefix
argument arg is nil, this uses calc-enter-result
as outlined above. Otherwise, it maps the function over several stack
elements; see Numeric Prefix Arguments. For example,
(defun calc-zeta (arg) (interactive "P") (calc-unary-op "zeta" 'calcFunc-zeta arg))
This function implements a binary operator, analogously to
calc-unary-op. The optional ident and unary
arguments specify the behavior when the prefix argument is zero or
one, respectively. If the prefix is zero, the value ident
is pushed onto the stack, if specified, otherwise an error message
is displayed. If the prefix is one, the unary function unary
is applied to the top stack element, or, if unary is not
specified, nothing happens. When the argument is two or more,
the binary function func is reduced across the top arg
stack elements; when the argument is negative, the function is
mapped between the next-to-top -arg stack elements and the
top element.
Return the number of elements on the stack as an integer. This count does not include elements that have been temporarily hidden by stack truncation; see Truncating the Stack.
Move the point to the nth stack entry. If n is zero, this will be the ‘.’ line. If n is from 1 to the current stack size, this will be the beginning of the first line of that stack entry’s display. If line numbers are enabled, this will move to the first character of the line number, not the stack entry itself.
Return the number of lines between the beginning of the nth stack entry and the bottom of the buffer. If n is zero, this will be one (assuming no stack truncation). If all stack entries are one line long (i.e., no matrices are displayed), the return value will be equal n+1 as long as n is in range. (Note that in Big mode, the return value includes the blank lines that separate stack entries.)
Erase the *Calculator* buffer and reformat its contents from memory. This must be called after changing any parameter, such as the current display radix, which might change the appearance of existing stack entries. (During a keyboard macro invoked by the X key, refreshing is suppressed, but a flag is set so that the entire stack will be refreshed rather than just the top few elements when the macro finishes.)