diff options
Diffstat (limited to 'manual')
| -rw-r--r-- | manual/manual/refman/exten.etex | 24 | ||||
| -rw-r--r-- | manual/manual/refman/typedecl.etex | 4 |
2 files changed, 25 insertions, 3 deletions
diff --git a/manual/manual/refman/exten.etex b/manual/manual/refman/exten.etex index 18309a9143..28e9c0deb4 100644 --- a/manual/manual/refman/exten.etex +++ b/manual/manual/refman/exten.etex @@ -1503,7 +1503,7 @@ typedef: ... | typedef item-attribute ; exception-definition: - 'exception' constr-name { attribute } [ 'of' typexpr { '*' typexpr } ] + 'exception' constr-decl | 'exception' constr-name '=' constr ; module-items: @@ -2096,3 +2096,25 @@ let invalid = function | Point p -> p (* INVALID *) | ... \end{verbatim} + + +\section{Local exceptions} +\ikwd{let\@\texttt{let}} +\ikwd{exception\@\texttt{exception}} + +(Introduced in OCaml 4.04) + +It is possible to define local exceptions in expressions: + +\begin{syntax} +expr: + ... + | "let" "exception" constr-decl "in" expr +\end{syntax} + + +The syntactic scope of the exception constructor is the inner +expression, but nothing prevents exception values created with this +constructor from escaping this scope. Two executions of the definition +above result in two incompatible exception constructors (as for any +exception definition). diff --git a/manual/manual/refman/typedecl.etex b/manual/manual/refman/typedecl.etex index 86f1043022..61315bc4fa 100644 --- a/manual/manual/refman/typedecl.etex +++ b/manual/manual/refman/typedecl.etex @@ -201,7 +201,7 @@ appear in the type equation and the type declaration. \begin{syntax} exception-definition: - 'exception' constr-name [ 'of' typexpr { '*' typexpr } ] + 'exception' constr-decl | 'exception' constr-name '=' constr \end{syntax} @@ -209,7 +209,7 @@ Exception definitions add new constructors to the built-in variant type \verb"exn" of exception values. The constructors are declared as for a definition of a variant type. -The form @'exception' constr-name ['of' typexpr {'*' typexpr}]@ +The form @'exception' constr-decl@ generates a new exception, distinct from all other exceptions in the system. The form @'exception' constr-name '=' constr@ gives an alternate name to an existing exception. |