Update dynamic scope explanation

[ctf.git] / common-trace-format-proposal.txt

diff --git a/common-trace-format-proposal.txt b/common-trace-format-proposal.txt
index e10c3dcc271f3e88ecf92ba5dfea00b3aefbbbe7..238fbadfead6c69709bcffad007f8478d558dd67 100644 (file)
--- a/common-trace-format-proposal.txt
+++ b/common-trace-format-proposal.txt
@@ -936,7 +936,8 @@ in Section 7.3.
 
 TSDL uses two different types of scoping: a lexical scope is used for
 declarations and type definitions, and a dynamic scope is used for
-variants references to tag fields.
+variants references to tag fields and for sequence references to length
+fields.
 
 7.3.1 Lexical Scope
 
@@ -953,16 +954,17 @@ typedef or typealias is allowed within a sub-scope.
 
 A dynamic scope consists in the lexical scope augmented with the
 implicit event structure definition hierarchy presented at Section 6.
-The dynamic scope is only used for variant tag definitions. It is used
-at definition time to look up the location of the tag field associated
-with a variant.
-
-Therefore, variants in lower levels in the dynamic scope (e.g. event
-context) can refer to a tag field located in upper levels (e.g. in the
-event header) by specifying, in this case, the associated tag with
-<header.field_name>. This allows, for instance, the event context to
-define a variant referring to the "id" field of the event header as
-selector.
+The dynamic scope is used for variant tag and sequence length
+definitions. It is used at definition time to look up the location of
+the tag field associated with a variant, and to lookup up the location
+of the length field associated with a sequence.
+
+Therefore, variants (or sequences) in lower levels in the dynamic scope
+(e.g. event context) can refer to a tag (or length) field located in
+upper levels (e.g. in the event header) by specifying, in this case, the
+associated tag with <header.field_name>. This allows, for instance, the
+event context to define a variant referring to the "id" field of the
+event header as selector.
 
 The target dynamic scope must be specified explicitly when referring to
 a field outside of the local static scope. The dynamic scope prefixes
@@ -1392,11 +1394,8 @@ assignment-operator:
 type-assignment-operator:
        :=
 
-constant-expression:
-       unary-expression
-
 constant-expression-range:
-       constant-expression ... constant-expression
+       unary-expression ... unary-expression
 
 2.2) Declarations:
 
@@ -1440,7 +1439,7 @@ type-specifier:
        ctf-type-specifier
 
 align-attribute:
-       align ( constant-expression )
+       align ( unary-expression )
 
 struct-specifier:
        struct identifier-opt { struct-or-variant-declaration-list-opt } align-attribute-opt
@@ -1466,7 +1465,7 @@ struct-or-variant-declarator-list:
 
 struct-or-variant-declarator:
        declarator
-       declarator-opt : constant-expression
+       declarator-opt : unary-expression
 
 variant-specifier:
        variant identifier-opt variant-tag-opt { struct-or-variant-declaration-list }
@@ -1488,7 +1487,7 @@ enumerator-list:
 
 enumerator:
        enumeration-constant
-       enumeration-constant = constant-expression
+       enumeration-constant = unary-expression
        enumeration-constant = constant-expression-range
 
 type-qualifier:
@@ -1501,7 +1500,6 @@ direct-declarator:
        identifier
        ( declarator )
        direct-declarator [ unary-expression ]
-       direct-declarator [ constant-expression ]
 
 abstract-declarator:
        pointer-opt direct-abstract-declarator
@@ -1510,7 +1508,6 @@ direct-abstract-declarator:
        identifier-opt
        ( abstract-declarator )
        direct-abstract-declarator [ unary-expression ]
-       direct-abstract-declarator [ constant-expression ]
        direct-abstract-declarator [ ]
 
 pointer: