Identifiers are used to give names to several classes of language
objects and refer to these objects by name later:
-
value names (syntactic class value-name),
- value constructors and
exception
constructors
(class constr-name),
- labels (label-name),
- variant tags (tag-name),
- type constructors (typeconstr-name),
- record fields (field-name),
- class names (class-name),
- method names (method-name),
- instance variable names (inst-var-name),
- module names (module-name),
- module type names (modtype-name).
These eleven name spaces are distinguished both by the context and by the
capitalization of the identifier: whether the first letter of the
identifier is in lowercase (written lowercase-ident below) or in
uppercase (written capitalized-ident). Underscore is considered a
lowercase letter for this purpose.
As shown above, prefix and infix symbols as well as some keywords can
be used as value names, provided they are written between parentheses.
The capitalization rules are summarized in the table below.
The keywords
'true', 'false', '[]', '()', and '::'
are no longer documented as constructor names (however, the
parser still seems to accepts them).
Name space |
Case of first letter |
Values |
lowercase |
Constructors |
uppercase |
Labels |
lowercase |
Variant tags |
uppercase |
Exceptions |
uppercase |
Type constructors |
lowercase |
Record fields |
lowercase |
Classes |
lowercase |
Instance variables |
lowercase |
Methods |
lowercase |
Modules |
uppercase |
Module types |
any |
Note on variant tags: the current implementation accepts
lowercase variant tags in addition to uppercase variant tags, but we
suggest you avoid lowercase variant tags for portability and
compatibility with future OCaml versions.
Referring to named objects |
|
A named object can be referred to either by its name (following the
usual static scoping rules for names) or by an access path prefix . name,
where prefix designates a module and name is the name of an object
defined in that module. The first component of the path, prefix, is
either a simple module name or an access path name1 . name2 ...,
in case the defining module is itself nested inside other modules.
For referring to type constructors or module types, the prefix can
also contain simple functor applications (as in the syntactic class
extended-module-path above), in case the defining module is the
result of a functor application.
Label names, tag names, method names and instance variable names need
not be qualified: the former three are global labels, while the latter
are local to a class.