From a3c2aecbff1dd82a26f3a69a3e1fdc04349b8d7a Mon Sep 17 00:00:00 2001
From: xchaos <xchaos@4bb87942-c103-4e5a-b51c-0ebff58f8515>
Date: Sun, 21 Sep 2008 11:19:45 +0000
Subject: [PATCH] multiple-evalution-of-args-safe versions of repeat() { } and
 for_range() { } macros

git-svn-id: https://dev.arachne.cz/repos/cll1h/trunk@88 4bb87942-c103-4e5a-b51c-0ebff58f8515
---
 cll1.h            |  8 +++++---
 demos/for_range.c | 47 ++++++++++++++++++++++++++++++++++++-----------
 demos/repeat.c    | 16 +++++++++++++---
 3 files changed, 54 insertions(+), 17 deletions(-)

diff --git a/cll1.h b/cll1.h
index 07c9189..356d70d 100644
--- a/cll1.h
+++ b/cll1.h
@@ -151,8 +151,8 @@ extern  unsigned RANDOM_SEED;
   /  7. C<<1 builtin iterators and conditionals, updated 2008-01-26 xCh.
  '----------------------------------------------------------------------- */
 #define loop while(TRUE)
-#define repeat(N) _NEW(I,0) while(_I++<N)
-#define for_range(VAR,FROM,TO) for( VAR=FROM ; FROM<=TO?VAR<=TO:VAR>=TO ; FROM<=TO?VAR++:VAR--)
+#define repeat(N) _NEW(I,0) _NEW(J,N) while(_I++<_J)
+#define for_range(VAR,FROM,TO) _NEW(I,FROM) _NEW(J,TO) for( VAR=_I ; _I<=_J?VAR<=_J:VAR>=_J ; _I<=_J?VAR++:VAR--)
 #define for_each(NODE,HEAD) for(NODE=HEAD; NODE; NODE=NODE->__next)
 #define for_search(NODE,HEAD,EXPR) for_each(NODE,HEAD) if(EXPR)
 #define for_file_lines(STR,FNAME) /* _NEW(CTX,get_context()) file_read(FNAME) for(use_context(_CTX),STR=file_line(_F);release_context(_M),(*S && !feof(_F));STR=file_line(_F),end_context()) _CATCH */
@@ -231,6 +231,7 @@ extern  _DECLARE_STRSTR;
   /  10. C<<1 private infrastructure, updated 2008-02-03 by xCh.
  '----------------------------------------------------------------------- */
 #define _I (_Iatom->I)
+#define _J (_Jatom->J)
 #define _S (_Satom->S)
 #define _F (_Fatom->F)
 #define _CTX (_CTXatom->CTX)
@@ -242,8 +243,9 @@ extern  _DECLARE_STRSTR;
 #define _FOR_VALID_COLUMNS(A,B,C) _NEW(I,0) for( prefix(A,B,C) ; A ; ((A!=B)&&prefix(A,B,C))||(A=NULL) ) if(*A&&++_I) 
 #define _NEW(NAME,VALUE) for(_##NAME##atom=get_mem(_##NAME##Atom),_##NAME##atom->NAME=(VALUE),_##NAME##atom->c=1,push(_##NAME##atom,_##NAME##stack);_##NAME##atom->c||(pop(_##NAME##atom,_##NAME##stack),0);_##NAME##atom->c--)
 #define _ANYSTACK(NAME) _##NAME##Atom _##NAME##atom,_##NAME##stack=NULL;
-#define _EXPORT_STACKS _ANYSTACK(I) _ANYSTACK(S) _ANYSTACK(F) _ANYSTACK(CTX)
+#define _EXPORT_STACKS _ANYSTACK(I) _ANYSTACK(J) _ANYSTACK(S) _ANYSTACK(F) _ANYSTACK(CTX)
 _ANYATOM(int,I);
+_ANYATOM(int,J);
 _ANYATOM(str,S);
 _ANYATOM(FILE *,F);
 _ANYATOM(void *,CTX);
diff --git a/demos/for_range.c b/demos/for_range.c
index 44a7b5b..c96f24c 100644
--- a/demos/for_range.c
+++ b/demos/for_range.c
@@ -2,25 +2,50 @@
 
 program
 {
- int i;
+ int i,j=1;
 
- echo("for_range(i,0,1)");
- for_range(i,0,1) printf(" [%d]",i);
+ echo("Just plain vanilla auto-increment:\tfor_range(i,1,5)");
+ for_range(i,1,5)
+ {
+  printf(" [%d]",i);
+ }
  print("");
 
- echo("for_range(i,1,0)");
- for_range(i,1,0) printf(" [%d]",i);
+ echo("Single-evaluation of macro argument:\tj=1; for_range(i,0,j++)");
+ for_range(i,0,j++)
+ {
+  printf(" [%d]",i);
+ }
  print("");
 
- echo("for_range(i,1,1)");
- for_range(i,1,1) printf(" [%d]",i);
+ echo("Just plain vanilla auto-decrement:\tfor_range(i,1,0)");
+ for_range(i,1,0)
+ {
+  printf(" [%d]",i);
+ }
  print("");
 
- echo("for_range(i,1,5)");
- for_range(i,1,5) printf(" [%d]",i);
+ echo("Single iteration is possible too:\tfor_range(i,1,1)");
+ for_range(i,1,1)
+ {
+  printf(" [%d]",i);
+ }
  print("");
 
- echo("for_range(i,5,1)");
- for_range(i,5,1) printf(" [%d]",i);
+ echo("Yet another example of macro safety:\tj=2; for_range(i,5,--j)");
+ for_range(i,5,--j)
+ {
+  printf(" [%d]",i);
+ } 
+ print("");
+
+ echo("Nesting of this macro seems to be safe:\tfor_range(i,1,3) for_range(j,3,1)");
+ for_range(i,1,3)
+ {
+  for_range(j,3,1)
+  {
+   printf(" [%d,%d]",i,j);
+  }
+ }
  print("");
 }
diff --git a/demos/repeat.c b/demos/repeat.c
index 70a5abe..b6229e9 100644
--- a/demos/repeat.c
+++ b/demos/repeat.c
@@ -2,9 +2,19 @@
 
 program
 {
- repeat(2)
+ int i=2;
+ 
+ repeat(1)
  {
-  print("Tohle cele delam 2x:");
-  repeat(3) print("Tohle delam 3x...");
+  print("This is demonstration, that nesting of C<<1 repeat(N) { ... } flow-control macro is completely safe:");
+  repeat(i++)
+  {
+   echo("Outer loop is supposed to be done twice: ");
+   repeat(i)
+   {
+    printf("[doing this %d times] ",i);
+   } 
+   print("... finished.");
+  }
  }
 }
-- 
2.30.2