PATCH: zcalc-auto-insert

[Peter Stephenson <p.stephenson@xxxxxxxxxxx>]

I came up with this, but I'm not sure how useful it actually is.

diff --git a/Doc/Zsh/contrib.yo b/Doc/Zsh/contrib.yo
index c446471..9eadc35 100644
--- a/Doc/Zsh/contrib.yo
+++ b/Doc/Zsh/contrib.yo
@@ -2449,6 +2449,25 @@ The style tt(whence) is available in the context tt(:zle:$WIDGET); this
 may be set to an array to give the command and options that will be used to
 investigate the command word found.  The default is tt(whence -c).
 )
+tindex(zcalc-auto-insert)
+item(tt(zcalc-auto-insert))(
+This function is useful together with the tt(zcalc) function described in
+ifzman(the section Mathematical Functions)\
+ifnzman(noderef(Mathematical Functions)).
+It should be bound to a key representing a binary operator such
+as `tt(PLUS())', `tt(-)', `tt(*)' or `tt(/)'.  When running in zcalc,
+if the key occurs at the start of the line or immediately following
+an open parenthesis, the text tt("ans ") is inserted before the
+representation of the key itself.  This allows easy use of the
+answer from the previous calculation in the current line.  The
+text to be inserted before the symbol typed can be modified by setting
+the variable tt(ZCALC_AUTO_INSERT_PREFIX).
+
+Hence, for example, typing `tt(PLUS()12)' followed by return adds 12
+to the previous result.
+
+When not in zcalc, the key simply inserts the symbol itself.
+)
 enditem()
 
 subsect(Utility Functions)
diff --git a/Functions/Misc/zcalc b/Functions/Misc/zcalc
index b796446..63f67ad 100644
--- a/Functions/Misc/zcalc
+++ b/Functions/Misc/zcalc
@@ -96,6 +96,9 @@
 emulate -L zsh
 setopt extendedglob
 
+# For testing in ZLE functions.
+local ZCALC_ACTIVE=1
+
 # TODO: make local variables that shouldn't be visible in expressions
 # begin with _.
 local line ans base defbase forms match mbegin mend psvar optlist opt arg
diff --git a/Functions/Zle/zcalc-auto-insert b/Functions/Zle/zcalc-auto-insert
new file mode 100644
index 0000000..c9a5c88
--- /dev/null
+++ b/Functions/Zle/zcalc-auto-insert
@@ -0,0 +1,8 @@
+# Bind to a binary operator keystroke for use with zcalc
+
+if [[ -n $ZCALC_ACTIVE ]]; then
+  if [[ $CURSOR -eq 0 || $LBUFFER[-1] = "(" ]]; then
+    LBUFFER+=${ZCALC_AUTO_INSERT_PREFIX:-"ans "}
+  fi
+fi
+zle .self-insert

pws