Differences

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--- language:langs:chp [2022/08/02 19:59]
rajit [An example]
+++ language:langs:chp [2023/01/02 07:39]
rajit [Channels in expressions]
@@ Line 158: / Line 158: @@
 If ''A'' is an input port, then ''A'' can participate in a //channel expression//. For example, we can write:
 <code act>
-*[[A=3 -> X!true;A?x
+[A=3 -> X!true;A?x
- []A!=3 -> X!false;A?x
+[]A!=3 -> X!false;A?x
- ]
+]
 </code>
 Here, ''A=3'' is a channel expression. This has the following meaning: first, wait for a value to be pending on the input channel ''A''; then compare it to 3. In other words, this expression includes an //implicit// probe. It also permits the pending value on ''A'' to be inspected. Note that ''A!=3'' //also includes waiting for a value to be pending on the input channel//, and is not the literal negation of the condition corresponding to ''A=3''. In other words, in the program fragment above, the selection statement should be read: wait for a value to be pending on input channel ''A''; if the value is 3, do the first set of statements; otherwise pick the second set of statements.
@@ Line 328: / Line 328: @@
 The CHP program:
 <code act>
-*[ L?x; R!x ]
+chp {
+   *[ L?x; R!x ]
+}
 </code>
 would be written in ''chp-txt'' as
 <code act>
-forever {
+chp-txt {
-   L?x; R!x
+   forever {
+      L?x; R!x
+   }
 }
 </code>
@@ Line 339: / Line 343: @@
 The CHP program:
 <code act>
-*[ L?x; [ x > 0 -> R!x [] else -> skip ] ]
+chp {
+   *[ L?x; [ x > 0 -> R!x [] else -> skip ] ]
+}
 </code>
 would be written
 <code act>
-forever {
+chp-txt {
-   recv (L, x);
+   forever {
-   select {
+      recv (L, x);
-     case x > 0 : send (R, x);
+      select {
-     else : skip
+        case x > 0 : send (R, x);
+        else : skip
+      }
    }
 }
 </code>