50648: Use $ZCALC_HISTORY where appropriate

ChangeLog

@@ -1,3 +1,8 @@
+2022-09-25  Peter Stephenson  <p.w.stephenson@ntlworld.com>
+
+	* 50648: Functions/Misc/zcalc: Julian Prein: Use ZCALC_HISTFILE
+	where defined for zcalc history.
+
 2022-09-21  Jun-ichi Takimoto  <takimoto-j@kba.biglobe.ne.jp>
 
 	* Nicholas Vinson: 50641: aczsh.m4, configure.ac: use 'int main()'

Doc/Zsh/contrib.yo

@@ -3972,8 +3972,11 @@ calculation is stored.  For example, the result of the calculation on the
 line preceded by `tt(4> )' is available as tt($4).  The last value
 calculated is available as tt(ans).  Full command line editing, including
 the history of previous calculations, is available; the history is saved in
-the file tt(~/.zcalc_history).  To exit, enter a blank line or type `tt(:q)'
-on its own (`tt(q)' is allowed for historical compatibility).
+the file tt($ZCALC_HISTFILE).  If tt($ZCALC_HISTFILE) is unset,
+tt($ZDOTDIR/.zcalc_history) is used instead, which in turn falls backs to
+tt($HOME/.zcalc_history) if tt($ZDOTDIR) is unset.  To exit, enter a blank
+line or type `tt(:q)' on its own (`tt(q)' is allowed for historical
+compatibility).
 
 A line ending with a single backslash is treated in the same fashion
 as it is in command line editing:  the backslash is removed, the

Functions/Misc/zcalc

@@ -124,8 +124,10 @@ integer _rpn_mode _matched _show_stack _i _n
 integer _max_stack _push
 local -a _expressions stack
 
+
 # We use our own history file with an automatic pop on exit.
-history -ap "${ZDOTDIR:-$HOME}/.zcalc_history"
+history -ap "${ZCALC_HISTFILE:-${ZDOTDIR:-$HOME}/.zcalc_history}"
+
 
 _forms=( '%2$g' '%.*g' '%.*f' '%.*E' '')