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--- language:syntacticreplication [2025/08/25 12:28] – [The core ACT language] rajit
+++ language:syntacticreplication [2025/09/04 11:12] (current) – [The core ACT language] rajit
@@ Line 1: / Line 1: @@
 ====== Syntactic Replication ======
-Syntactic replication is a useful construct that can be used in a variety of places. The syntactic replication construct is written as follows:
+Syntactic replication (sometimes called a syntactic loop construct) is a useful construct that can be used in a variety of places. The syntactic replication construct is written as follows:
 <code act>
 (sym id : range : body(id) )
 </code>
-The ''sym'' (symbol) might be empty. ''id'' is a variable that can be used in ''body(id)'', and takes the range specified by ''range''. ''range'' can be either an integer-valued expression or ''start .. end'' to indicate a start and end index. The result of the replication is
+The ''sym'' (symbol) might be empty. ''id'' is a variable that can be used in the ''body(id)'', and takes the range specified by ''range''. ''range'' can be either an integer-valued expression or ''start .. end'' to indicate a start and end index. The integer value of "id" is substituted into "body(id)" when the replication construct is expanded out. The result of the replication is
 <code act>
  body(lo) sym body(lo+1) sym ... sym body(hi)
 </code>
 where ''lo'' is the starting index of the range, and ''hi'' is the ending index. What follows are different forms of the same construct that can be used in ACT.
 ===== The core ACT language =====
@@ Line 21: / Line 23: @@
   b[0].R = b[1].L; b[1].R = b[2].L; ... b[8].R = b[9].L;
 </code>
+In this particular case, the separator is empty.
 Another example is:
@@ Line 54: / Line 57: @@
 ]
 </code>
+In this scenario, the separator is the ''[]'' operator that is used to separate guarded actions.
-===== Expressions =====
+===== CHP =====
+CHP also supports syntactic replication for guards like the core language((CHP is more strict about placement of semicolons. The language uses semicolons as a separator unlike software languages like C/C++, so please keep this in mind!)). In addition, CHP permits
+syntactic replication for sequential and parallel composition, as illustrated in the following examples:
+Sequential composition:
+<code act>
+(; i : 5 : x.d[i]-; y := y + 1 )
+</code>
+Parallel composition:
+<code act>
+(, i : 5 : x.d[i]-)
+</code>
+CHP expressions also support some forms of syntactic replication. The following binary operators allow syntactic replication:
+   * Logical or bitwise and (''&'')
+   * Logical or bitwise or (''|'')
+   * Bitwise exclusive or (''^'')
+   * Addition (''+'')
+   * Multiplication (''*'')
+This means you can write statements like:
+<code act>
+  x := (+ i : 5 : a[i])
+</code>
+===== Dataflow =====
+Split and merge operators in the dataflow language can use syntactic replication. This is primarily through comma-separated operators, as in the following parameterized N-way split:
+<code act>
+dataflow {
+  {ctrl} l -> (, i : N : out[i])
+ }
+</code>
+===== PRS =====
+Production rules support both simple syntactic replication as well as syntactic replication in expressions.
+Simple replication:
+<code act>
+prs {
+   (i : 5 : Reset -> x[i]-)   // simple replication of production rule
+}
+</code>
+Expressions to create a single N-input NAND gate:
+<code act>
+prs {
+   (&i : N : x[i]) -> y-
+   (|i : N : ~x[i]) -> y+
+}
+</code>
+===== Sizing =====
+The sizing body also supports syntactic replication.
+<code act>
+sizing {
+   ...
+   (; i : 5 : out[i] {-1});
+   ...
+}
+</code>