Merge remote-tracking branch 'upstream/main' into replace-madoko-spec…

…-with-asciidoc-try4

Signed-off-by: Andy Fingerhut <[email protected]>

p4-16/spec/P4-16-spec.adoc

@@ -5479,6 +5479,7 @@ statement
     | exitStatement
     | returnStatement
     | switchStatement
+    | loopStatement
     ;
 
 include::grammar.adoc[tag=assignmentOrMethodCallStatement]
@@ -5727,6 +5728,43 @@ See "Implementing generalized P4_16 switch statements"
 for possible techniques that one might
 use to implement generalized switch statements.footnote:GeneralizedSwitchStatements[<https://github.com/p4lang/p4-spec/blob/master/p4-16/spec/docs/implementing-generalized-switch-statements.md>]
 
+[#sec-loop-stmt]
+=== Loop statement
+
+A `loop` statement executes a statement zero or more times, based on a
+condition or a range or collection.
+
+[source,bison]
+----
+include::grammar.adoc[tag=loopStatement]
+
+include::grammar.adoc[tag=forInitStatement]
+
+include::grammar.adoc[tag=forUpdateStatement]
+----
+
+The basic 3-clause `for` statement is similar to a C for statement.  The init statements
+will be executed prior to executing the loop.  The condition will be evaluated before
+each iteration, to determine if the loop should exit.  If the condition is false, the loop
+will exit without executing any statements from the loop body or update.
+The update statements will be executed after the loop body and before evaluating the
+condition again for the next iteration.
+
+The `for`-`in` statement executes the body once for each value in a range or each
+element in a list expression or header stack.  The list or range expression itself
+will only be evaluated once, before the first iteration of the loop.  All side effects
+in the list or range expression will occur before the first iteration of the loop body.
+
+A `break;` statement may be executed in a loop body to immediately exit the loop,
+without executing the rest of the body or the update statements.
+
+A `continue;` statement may be executed in a loop body to skip the rest of the current
+loop body, executing the update statements and then evaluating the condition to
+either execute the loop body again, or terminate the loop.
+
+The scope of any declaration in a for statement is limited to the for statement and its body.
+
+>>>>>>> upstream/main:p4-16/spec/P4-16-spec.mdk
 [#sec-packet-parsing]
 == Packet parsing
 

p4-16/spec/grammar.adoc

@@ -98,7 +98,9 @@ annotationToken
     | APPLY
     | BOOL
     | BIT
+    | BREAK
     | CONST
+    | CONTINUE
     | CONTROL
     | DEFAULT
     | ELSE
@@ -108,6 +110,7 @@ annotationToken
     | EXIT
     | EXTERN
     | FALSE
+    | FOR
     | HEADER
     | HEADER_UNION
     | IF
@@ -737,6 +740,18 @@ assignmentOrMethodCallStatement
     ;
 // end::assignmentOrMethodCallStatement[]
 
+// tag::breakStatement[]
+breakStatement
+    : BREAK ";"
+    ;
+// end::breakStatement[]
+
+// tag::continueStatement[]
+continueStatement
+    : CONTINUE ";"
+    ;
+// end::continueStatement[]
+
 // tag::emptyStatement[]
 emptyStatement
     : ";"
@@ -779,7 +794,10 @@ statement
     | blockStatement
     | returnStatement
     | exitStatement
+    | breakStatement
+    | continueStatement
     | switchStatement
+    | loopStatement
     ;
 
 // tag::blockStatement[]
@@ -822,6 +840,66 @@ switchLabel
     ;
 // end::switchLabel[]
 
+// tag::loopStatement[]
+loopStatement
+    : optAnnotations FOR "(" optForInitStatements ";" expression ";"
+      optForUpdateStatements ")" statement
+    | optAnnotations FOR "(" typeRef name IN forCollectionExpr ")" statement
+    ;
+// end::loopStatement[]
+
+// tag::optForInitStatements[]
+optForInitStatements
+    : /* empty */
+    | forInitStatements
+    ;
+// end::optForInitStatements[]
+
+// tag::forInitStatements[]
+forInitStatements
+    : forInitStatement
+    | forInitStatements "," forInitStatement
+    ;
+// end::forInitStatements[]
+
+// tag::forInitStatement[]
+forInitStatement
+    : optAnnotations typeRef name optInitializer
+    | lvalue "(" argumentList ")"
+    | lvalue "<" typeArgumentList ">" "(" argumentList ")"
+    | lvalue "=" expression
+    ;
+// end::forInitStatement[]
+
+// tag::optForUpdateStatements[]
+optForUpdateStatements
+    : /* empty */
+    | forUpdateStatements
+    ;
+// end::optForUpdateStatements[]
+
+// tag::forUpdateStatements[]
+forUpdateStatements
+    : forUpdateStatement
+    | forUpdateStatements "," forUpdateStatement
+    ;
+// end::forUpdateStatements[]
+
+// tag::forUpdateStatement[]
+forUpdateStatement
+    : lvalue "(" argumentList ")"
+    | lvalue "<" typeArgumentList ">" "(" argumentList ")"
+    | lvalue "=" expression
+    ;
+// end::forUpdateStatement[]
+
+// tag::forCollectionExpr[]
+forCollectionExpr
+    : expression
+    | expression ".." erxpression
+    ;
+// end::forCollectionExpr[]
+
 // tag::statementOrDeclaration[]
 statementOrDeclaration
     : variableDeclaration