Lua 3.13.1

1 files changed, 33 insertions, 0 deletions

diff --git a/test/trace.lua b/test/trace.lua
new file mode 100644
index 00000000..5f32a8f9
--- /dev/null
+++ b/test/trace.lua
@@ -0,0 +1,33 @@
+-- shows how to trace assigments to global variables
+
+T=newtag()				-- tag for tracing
+
+function Ttrace(name)			-- trace a global variable
+  local t={}
+  settag(t,T)
+  rawsetglobal(name,t)
+end
+
+function Tsetglobal(name,old,new)
+  write("tracing: ",name," now is ",new,"\n")
+  old.value=new 
+end
+
+function Tgetglobal(x,value)		-- get the actual value
+  return value.value
+end
+
+settagmethod(T,"getglobal",Tgetglobal)
+settagmethod(T,"setglobal",Tsetglobal)
+
+-- now show it working
+
+Ttrace("a")
+Ttrace("c")
+
+a=1
+b=2
+c=3
+a=10
+b=20
+c=30