Differences

This shows you the differences between two versions of the page.

--- language:controlflow [2019/04/18 14:22]
rajit
+++ language:controlflow [2020/12/02 01:00]
127.0.0.1 external edit
@@ Line 78: / Line 78: @@
 ===== Selections =====
+Conditional execution is supported by the selection statement. The
+syntax of a selection statement is:
+<code>
+[ boolean_expression -> body
+[] boolean_expression -> body
+..
+]
+</code>
+The last Boolean expression in the conditional can be the keyword
+''else'', which is short-hand for 'all other guards are false.'
+Any one body whose corresponding Boolean expression is true is
+executed. For instance, we can create 32 registers with
+something special for register 0 as follows:
+<code>
+(i : 32 :
+    [ i = 0 -> r0(in[i],out[i],control);
+   [] else -> r[i](in[i],out[i],control);
+    ]
+)
+</code>
+Boolean expressions can be constructed from Boolean variables, the
+constants ''true'' and ''false'', and the Boolean operators
+''&'', ''|'', and ''~'' denoting the and, or, and negation
+operations respectively.  Numeric expressions can be compared using
+''<'', ''< ='', ''>'', ''>='', ''='', and ''!='' for
+the operators less than, less than or equal to, greater than, greater
+than or equal to, equal to, and not equal to respectively.
+===== Recursion =====
+Type definitions can be recursive. For instance, the following
+definition can be used to create a tree structure.
+<code>
+template<pint N>
+defproc tree (bool a[N])
+{
+  [ N = 1 -> leaf l(a[0]);
+ [] N > 1 -> tree<N/2> t0(a[0..N/2-1]);
+             tree<N-N/2> t1(a[N/2..N-1]);
+  ]
+}
+</code>