From 80f5cef01abdaee3b8c818ea07f534570e94c6d4 Mon Sep 17 00:00:00 2001
From: dos-reis <gdr@axiomatics.org>
Date: Sun, 14 Oct 2007 03:36:45 +0000
Subject: 	* ast.boot.pamphlet (bfGetOldBootName): New. 
 (bfSameMeaning): Likewise. 	(bfReName): Use them. 	* parser.boot.pamphlet
 (bpCompare): Tidy. 	* tokens.boot.pamphlet: Rename NE to SHOENE.  Record
 Old Boot 	renaming tokens. Likewise for tokens with same meaning. 
 * translator.boot.pamphlet (AxiomCore::%sysInit): New. 
 ($translatingOldBoot): Likewise.

---
 src/boot/ast.boot.pamphlet | 40 +++++++++++++++++++++++++++++++++++-----
 1 file changed, 35 insertions(+), 5 deletions(-)

(limited to 'src/boot/ast.boot.pamphlet')

diff --git a/src/boot/ast.boot.pamphlet b/src/boot/ast.boot.pamphlet
index 25d982f5..761175bc 100644
--- a/src/boot/ast.boot.pamphlet
+++ b/src/boot/ast.boot.pamphlet
@@ -664,12 +664,42 @@ bfApplication(bfop, bfarg) ==
          then cons(bfop,CDR bfarg)
          else cons(bfop,[bfarg])
  
- 
+
+++ Token renaming.  New Boot and Old Boot differs in the set of
+++ tokens they rename.  When converting code written in Old Boot
+++ to New Boot, it is helpful to have some noise about potential
+++ divergence in semantics.  So, when compiling with --boot=old,
+++ we compute the renaming in both Old Boot and New Boot and compare
+++ the results.  If they differ, we prefer the old meaning, with some
+++ warnings.  Notice that the task is compounded by the fact the
+++ tokens in both language do not always agreee.
+++ However, to minimize the flood of false positive, we
+++ keep a list of symbols which apparently differ in meanings, but
+++ which have been verified to agree.  
+++ This is a valuable automated tool during the transition period.
+
+-- return the meaning of the x in Old Boot.
+bfGetOldBootName x ==
+  a := GET(x, "OLD-BOOT") => car a
+  x
+
+-- returns true if x has same meaning in both Old Boot and New Boot.
+bfSameMeaning x ==
+  GET(x, 'RENAME_-OK)
+ 
+-- returns the meaning of x in the appropriate Boot dialect.
 bfReName x==
-   a:=GET(x,"SHOERENAME")
-   if a
-   then car a
-   else  x
+  newName :=
+    a := GET(x,"SHOERENAME") => car a
+    x
+  $translatingOldBoot and not bfSameMeaning x =>
+    oldName := bfGetOldBootName x
+    if newName ^= oldName then
+       warn [PNAME x, '" as `", PNAME newName, _
+             '"_' differs from Old Boot `", PNAME oldName, '"_'"]
+    oldName
+  newName
+
  
 bfInfApplication(op,left,right)==
    EQ(op,"EQUAL") => bfQ(left,right)
-- 
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