diff options
| -rw-r--r-- | system/doc/reference_manual/typespec.xml | 10 | 
1 files changed, 7 insertions, 3 deletions
| diff --git a/system/doc/reference_manual/typespec.xml b/system/doc/reference_manual/typespec.xml index c117b6e1d0..a0ea41cb3b 100644 --- a/system/doc/reference_manual/typespec.xml +++ b/system/doc/reference_manual/typespec.xml @@ -142,8 +142,8 @@    PairList :: Pair              | Pair, PairList -  Pair :: Type := Type                         %% denotes a pair that must be present -        | Type => Type +  Pair :: Type := Type                         %% denotes a mandatory pair +        | Type => Type                         %% denotes an optional pair    TList :: Type           | Type, TList @@ -176,7 +176,11 @@      The general form of maps is <c>#{PairList}</c>. The key types in      <c>PairList</c> are allowed to overlap, and if they do, the      leftmost pair takes precedence. A map pair has a key in -    <c>PairList</c> if it belongs to this type. +    <c>PairList</c> if it belongs to this type. A <c>PairList</c> may contain +    both 'mandatory' and 'optional' pairs where 'mandatory' denotes that +    a key type, and its associated value type, must be present. +    In the case of an 'optional' pair it is not required for the key type to +    be present.    </p>    <p>      Notice that the syntactic representation of <c>map()</c> is | 
