virtual (--)

Inputs

• None.

Outputs

• None.

virtual is the declaration modifier that marks the next successfully created local as static.

The name is historical. The resulting field-storage property is what fieldIsVirtual reports. The schema-level Meta test is virtual?.

The builtin sets a pending static specifier in the current scope. That pending specifier is consumed by the next successful local creation through NAME: ...; or def.

Behavior

• If the static specifier is already pending, the builtin raises a duplicate-specifier error.
• After the next successful local creation, the pending static flag is cleared.
• Other operations do not consume the pending static flag.
• A pending static flag is invalid for exportFunction, importFunction, and importVariable.
• If the scope ends before the pending static flag is consumed, the program is invalid.
• Pending overload or private specifiers coexist with the pending static flag.
• This does not make the resulting object Meta.

Example

{} 0 {} [
  virtual staticLocal: 1;
  dict: { virtual 2 "staticField" def };

  "-- values created with virtual are static, not meta --" printCompilerMessage
  staticLocal printStack _:;
  staticLocal virtual? printStack _:;
  dict.staticField printStack _:;
  dict.staticField virtual? printStack _:;

  "-- fieldIsVirtual sees static field storage --" printCompilerMessage
  dict 0 fieldIsVirtual printStack _:;

  0
] "main" exportFunction

Expected Output During Compilation

-- values created with virtual are static, not meta --
1
FALSE
2
FALSE
-- fieldIsVirtual sees static field storage --
TRUE

See also

• NAME: ...; node — Pushes a name onto the name stack and creates a local by consuming that name and one data-stack object.
• def builtin (object name --) Creates a named local or field using a known Text name.
• exportFunction builtin (inputsSchema output options callable name --) Exports a named function built from a Block and a signature; a pending virtual specifier is invalid there.
• importFunction builtin (inputsSchema output options name --) Declares or imports a named function with the supplied signature; a pending virtual specifier is invalid there.
• importVariable builtin (schema name --) Creates a local that refers to external variable storage; a pending virtual specifier is invalid there.
• fieldIsVirtual builtin (schema ordinal -- hasNoStorage) No-storage test for one selected item.
• static builtin (--) Reserved builtin name with no standalone effect.
• virtual? builtin (schema -- isMeta) Historical Meta-schema test.