X-Git-Url: https://git.octo.it/?a=blobdiff_plain;f=doc%2Frpntutorial.pod;h=b3beac1ded0735012874a4340affb79b1a833e38;hb=c1f4d92a5b64793471b6a4ca78ec7fa71db18df9;hp=9829eb82b8476106b5017fb92406f34e903d5c91;hpb=4b7345f9345915c8061e4b37b26ce8887828c973;p=rrdtool.git
diff --git a/doc/rpntutorial.pod b/doc/rpntutorial.pod
index 9829eb8..b3beac1 100644
--- a/doc/rpntutorial.pod
+++ b/doc/rpntutorial.pod
@@ -2,8 +2,6 @@
rpntutorial - Reading RRDtool RPN Expressions by Steve Rader
-=for html
-
=head1 DESCRIPTION
This tutorial should help you get to grips with RRDtool RPN expressions
@@ -26,7 +24,7 @@ RPN expression 2,1,GT evaluates to 1.
Now consider "2,1,LE". This RPN expression could be read as "is
two less than or equal to one?". The natural response is "no"
-and thus the RPN expression 2,1,LE evaluates to 0.
+and thus the RPN expression 2,1,LE evaluates to 0.
=head1 Reading the IF Operator
@@ -78,7 +76,7 @@ with multiple logic operators:
1) 20,10,GT,10,20,IF eval is 20,10,GT = 1 result is 1,10,20,IF
read the eval as pop "20 is greater than 10" so push 1
-
+
2) 1,10,20,IF eval is 1,10,20,IF = 10 result is 10
read pop "if 1 then 10 else 20" so push 10. Only 10 is left so
@@ -96,15 +94,11 @@ multiplication operator:
Now let's go back to the first example of multiple logic operators,
but replace the value 20 with the variable "input":
-=for comment
-XXX wo kommt das A ploetzlich her? Hier braucht es einen Satz, dass A als
-XXX placeholder zum Lesbarmachen verwendet wird (shortcut).
-
- 1) input,10,GT,10,input,IF eval is input,10,GT result is A
+ 1) input,10,GT,10,input,IF eval is input,10,GT ( lets call this A )
Read eval as "if input > 10 then true" and replace "input,10,GT"
with "A":
-
+
2) A,10,input,IF eval is A,10,input,IF
read "if A then 10 else input". Now replace A with it's verbose
@@ -145,7 +139,7 @@ traditional notation. Explain why they have different answers.
Answer 1:
3*2+1 = 7 and 3*(2+1) = 9. These expressions have
- different answers because the altering of the plus and
+ different answers because the altering of the plus and
times operators alter the order of their evaluation.