From 948133b053ddb31b9845bf81f28b23c1a9d23701 Mon Sep 17 00:00:00 2001
From: Kaz Kylheku <kaz@kylheku.com>
Date: Tue, 30 Oct 2018 17:57:11 -0700
Subject: Hide deprecated, undocumented variables.

* arith.c (arith_init): Do not define *flo-dig*, *flo-max*,
*flo-min*, *flo-epsilon*, *pi* and *e* unless compatibility
with TXR 199 or earlier is requested.

* txr.c (txr_main): Likewise for *self-path*.

* txr.1: Compat note added.
---
 arith.c | 19 +++++++++++++------
 txr.1   |  4 ++++
 txr.c   |  3 ++-
 3 files changed, 19 insertions(+), 7 deletions(-)

diff --git a/arith.c b/arith.c
index 493492a3..b1fe876c 100644
--- a/arith.c
+++ b/arith.c
@@ -46,6 +46,7 @@
 #include "args.h"
 #include "eval.h"
 #include "itypes.h"
+#include "txr.h"
 #include "arith.h"
 
 #define TAG_PAIR(A, B) ((A) << TAG_SHIFT | (B))
@@ -3173,10 +3174,13 @@ void arith_init(void)
   mp_neg(&INT_PTR_MAX_SUCC_MP, &INT_PTR_MAX_SUCC_MP);
   log2_init();
 
-  reg_varl(intern(lit("*flo-dig*"), user_package), num_fast(DBL_DIG));
-  reg_varl(intern(lit("*flo-max*"), user_package), flo(DBL_MAX));
-  reg_varl(intern(lit("*flo-min*"), user_package), flo(DBL_MIN));
-  reg_varl(intern(lit("*flo-epsilon*"), user_package), flo(DBL_EPSILON));
+  if (opt_compat && opt_compat <= 199) {
+    reg_varl(intern(lit("*flo-dig*"), user_package), num_fast(DBL_DIG));
+    reg_varl(intern(lit("*flo-max*"), user_package), flo(DBL_MAX));
+    reg_varl(intern(lit("*flo-min*"), user_package), flo(DBL_MIN));
+    reg_varl(intern(lit("*flo-epsilon*"), user_package), flo(DBL_EPSILON));
+  }
+
   reg_varl(intern(lit("flo-dig"), user_package), num_fast(DBL_DIG));
   reg_varl(intern(lit("flo-max-dig"), user_package), num_fast(FLO_MAX_DIG));
   reg_varl(intern(lit("flo-max"), user_package), flo(DBL_MAX));
@@ -3188,14 +3192,17 @@ void arith_init(void)
 #ifndef M_PI
 #define M_PI 3.14159265358979323846
 #endif
-  reg_varl(intern(lit("*pi*"), user_package), flo(M_PI));
   reg_varl(intern(lit("%pi%"), user_package), flo(M_PI));
 #ifndef M_E
 #define M_E 2.71828182845904523536
 #endif
-  reg_varl(intern(lit("*e*"), user_package), flo(M_E));
   reg_varl(intern(lit("%e%"), user_package), flo(M_E));
 
+  if (opt_compat && opt_compat <= 199) {
+    reg_varl(intern(lit("*pi*"), user_package), flo(M_PI));
+    reg_varl(intern(lit("*e*"), user_package), flo(M_E));
+  }
+
   reg_fun(intern(lit("signum"), user_package), func_n1(signum));
 
   reg_fun(intern(lit("bignum-len"), user_package), func_n1(bignum_len));
diff --git a/txr.1 b/txr.1
index 073d8df8..69e75b52 100644
--- a/txr.1
+++ b/txr.1
@@ -64906,6 +64906,10 @@ of these version values, the described behaviors are provided if
 is given an argument which is equal or lower. For instance
 .code "-C 103"
 selects the behaviors described below for version 105, but not those for 102.
+.IP 199
+After \*(TX 199, certain global variables that had been deprecated
+for a long time, and no longer documented, were removed. Requesting 199 or
+earlier compatibility restores those variables.
 .IP 190
 Until \*(TX 190, the
 .code reset-struct
diff --git a/txr.c b/txr.c
index 1ef43001..9dda1cc6 100644
--- a/txr.c
+++ b/txr.c
@@ -1022,7 +1022,8 @@ int txr_main(int argc, char **argv)
 
     opt_loglevel = match_loglevel;
 
-    reg_var(intern(lit("*self-path*"), user_package), spec_file_str);
+    if (opt_compat && opt_compat <= 199)
+      reg_var(intern(lit("*self-path*"), user_package), spec_file_str);
 
     if (parser.errors) {
       if (enter_repl)
-- 
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