* lisp/calc/: Use lexical scoping in all the files

Includes the following pervasive changes:
- Move some defvars earlier in the file so they cover earlier let-bindings
- Change dynamically scoped `calc-FOO` or `math-FOO` function arguments
  to just FOO and then let-bind the `calc-FOO` or `math-FOO` variable
  explicitly in the body of the function.  In some cases, the
  beginning of the function was changed to refer to FOO so as to delay
  the binding to a nearby `let` when I could ensure that it did
  not make a difference.
- Add an underscore in front of unused vars or comment them out altogether.
- Replace unused `err` arg to `condition-case` with nil.

Plus the additional itemized changes below.

* lisp/calc/calc-map.el (calcFunc-reducer):
* lisp/calc/calc-arith.el (math-setup-declarations):
* lisp/calc/calc-help.el (calc-full-help, calc-help-index-entries)
(calc-full-help): Use `ignore-errors`.

* lisp/calc/calc-embed.el (calc-embedded-modes-change):
Declare `the-language` and `the-display-just` as dynamically scoped.

* lisp/calc/calc-forms.el (math-setup-year-holidays): Use `dolist`.

* lisp/calc/calc-graph.el (calc-graph-set-styles): Use `symbol-value`
rather than `eval.`
(calc-graph-delete-temps, calc-graph-set-styles): Use ignore-errors.

* lisp/calc/calc-macs.el (calc-with-trail-buffer): Add artificial use
of `save-buf` to silence compiler warnings in all the cases where
`body` doesn't make use of it.

* lisp/calc/calc-math.el (math-largest-emacs-expt)
(math-smallest-emacs-expt, math-use-emacs-fn): Use ignore-errors.

* lisp/calc/calc-mode.el (calc-total-algebraic-mode): Remove "P" from
interactive spec since it's not used anyway.

* lisp/calc/calc-rewr.el (calc-match): Simplify.

* lisp/calc/calc.el (calc-buffer): Give it a global nil value,
so it's automatically declared dynbound in any file that requires `calc`.
(calcDigit-nondigit): Adjust accordingly.

* lisp/calc/calcalg2.el (calcFunc-table): Declare `var-dummy` as dynbound.
(math-scan-for-limits): Comment out dead code.

* lisp/calc/calcalg3.el (math-general-fit): Declare `var-YVAL` and
`var-YVALX` as dynbound.

1 files changed, 17 insertions, 14 deletions

diff --git a/lisp/calc/calc-vec.el b/lisp/calc/calc-vec.el
index 6850ded717b..875414595cf 100644
--- a/lisp/calc/calc-vec.el
+++ b/lisp/calc/calc-vec.el
@@ -1,4 +1,4 @@
-;;; calc-vec.el --- vector functions for Calc
+;;; calc-vec.el --- vector functions for Calc  -*- lexical-binding:t -*-
 
 ;; Copyright (C) 1990-1993, 2001-2020 Free Software Foundation, Inc.
 
@@ -1111,18 +1111,20 @@
 ;; by calcFunc-grade and calcFunc-rgrade.
 (defvar math-grade-vec)
 
-(defun calcFunc-grade (math-grade-vec)
-  (if (math-vectorp math-grade-vec)
-      (let* ((len (1- (length math-grade-vec))))
-	(cons 'vec (sort (cdr (calcFunc-index len)) 'math-grade-beforep)))
-    (math-reject-arg math-grade-vec 'vectorp)))
-
-(defun calcFunc-rgrade (math-grade-vec)
-  (if (math-vectorp math-grade-vec)
-      (let* ((len (1- (length math-grade-vec))))
+(defun calcFunc-grade (grade-vec)
+  (if (math-vectorp grade-vec)
+      (let* ((math-grade-vec grade-vec)
+             (len (1- (length grade-vec))))
+	(cons 'vec (sort (cdr (calcFunc-index len)) #'math-grade-beforep)))
+    (math-reject-arg grade-vec #'vectorp)))
+
+(defun calcFunc-rgrade (grade-vec)
+  (if (math-vectorp grade-vec)
+      (let* ((math-grade-vec grade-vec)
+	     (len (1- (length grade-vec))))
 	(cons 'vec (nreverse (sort (cdr (calcFunc-index len))
-				   'math-grade-beforep))))
-    (math-reject-arg math-grade-vec 'vectorp)))
+				   #'math-grade-beforep))))
+    (math-reject-arg grade-vec #'vectorp)))
 
 (defun math-grade-beforep (i j)
   (math-beforep (nth i math-grade-vec) (nth j math-grade-vec)))
@@ -1556,7 +1558,8 @@ of two matrices is a matrix."
 (defvar math-exp-keep-spaces)
 (defvar math-expr-data)
 
-(defun math-read-brackets (space-sep math-rb-close)
+(defun math-read-brackets (space-sep rb-close)
+  (let ((math-rb-close rb-close))
   (and space-sep (setq space-sep (not (math-check-for-commas))))
   (math-read-token)
   (while (eq math-exp-token 'space)
@@ -1624,7 +1627,7 @@ of two matrices is a matrix."
 	    (throw 'syntax "Expected `]'")))
       (or (eq math-exp-token 'end)
 	  (math-read-token))
-      vals)))
+      vals))))
 
 (defun math-check-for-commas (&optional balancing)
   (let ((count 0)