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global_op(+Precedence, +Associativity, ++Name)

Defines the global operator(s) in Name to have precedence Precedence and associativity Associativity. If Precedence is 0 then the operator definition is removed.

Precedence: Integer
Associativity: Atom
Name: Atom or List of atoms

This built-in predicate is obsolete!

Description

Defines Name as an operator of precedence Precedence and associativity Associativity. Name may be a single operator or a list of operators, in which each is given the specified precedence and associativity.

The operator is defined to be globally available, ie. visible in every module, unless hidden by a local operator.

Precedence is an integer in the range 0 to 1200. If the precedence is 0 the definition of the operator is removed.

Associativity must be one of the following atoms:

 xfx           infix
 xfy           infix
 yfx           infix
 fx            prefix
 fy            prefix
 xf            postfix
 yf            postfix

x represents an argument whose precedence must be lower than that of the operator. y represents an argument whose precedence must be lower or equal to that of the operator.

Prefix, infix and postfix operators are independent of each other and may coexist. See the manual chapter on syntax about how ambiguities are resolved in this case.

Modes and Determinism

global_op(+, +, ++) is det

Modules

This predicate is sensitive to its module context (tool predicate, see @/2).

Exceptions

(4) instantiation fault: Any of the input arguments is uninstantiated.
(5) type error: Precedence is not an integer.
(5) type error: Name is not an atom or list of atoms.
(6) out of range: Precedence is not in range 0 to 1200.
(6) out of range: Associativity is not xf, xfx, fy etc.
(43) illegal operator definition: Multiple definition of postfix and infix for Name.

Examples

Success:
   [eclipse]: global_op(100,fx,hello).  % define prefix operator

   yes.
   [eclipse]: read(X).
   > hello david.                       % read using operator

   X = hello david
   yes.
   [eclipse]: global_op(200, xfy, -+-),
            global_op(300, fx, -+-).    % multiple infix/prefix

   yes.
   [eclipse]: global_op(100,xfx,[a,b,c,d]).  % define list of op's

   yes.
   [eclipse]: current_op(100,xfx,Y).    % return defined op's

   Y = d     More? (;)

   Y = a     More? (;)

   Y = c     More? (;)

   Y = b     More? (;)                  % RETURN pressed

   yes.
   [eclipse]: global_op(300,xfy,?), global_op(300,yfx,:).

   yes.
   [eclipse]: display(a ? b ? c), display(a : b : c).
   ?(a, ?(b, c))                   % xfy operator

   :(:(a, b), c)                   % yfx operator
   yes.
   [eclipse]:

Error:
   global_op(X,fx,aaa).             (Error 4)
   global_op(a,fx,aaa).             (Error 5)
   global_op(100,xfx,1).            (Error 5)
   global_op(100,abc,fred).         (Error 6)

   global_op(100,xfx,aaa),global_op(100,xf,aaa).     (Error 43)