Sollya User's Manual

Name:

bind partially applies a procedure to an argument, returning a procedure with one argument less

Usage:

bind(proc, ident, obj) : (procedure, identifier type, any type) -> procedure

Parameters:

proc is a procedure to be partially applied to an argument
ident is one of the formal arguments of proc
obj is any Sollya object ident is to be bound to

Description:

bind allows a formal parameter ident of a procedure proc to be bound to an object obj, hence proc to be partially applied. The result of this curryfied application, returned by bind, is a procedure with one argument less. This way, bind permits specialization of a generic procedure, parameterized e.g. by a function or range.
In the case when proc does not have a formal parameter named ident, bind prints a warning and returns the procedure proc unmodified.
bind always returns a procedure, even if proc only has one argument, which gets bound to ident. In this case, bind returns a procedure which does not take any argument. Hence evaluation, which might provoke side effects, is only performed once the procedure gets used.
bind does not work on procedures with an arbitrary number of arguments.

Example 1:

   > procedure add(X,Y) { return X + Y; };
   > succ = bind(add,X,1);
   > succ(5);
   6
   > succ;
   proc(Y)
   {
   nop;
   return (proc(X, Y)
   {
   nop;
   return (X) + (Y);
   })(1, Y);
   }

Example 2:

   > procedure add(X,Y) { return X + Y; };
   > succ = bind(add,X,1);
   > five = bind(succ,Y,4);
   > five();
   5
   > five;
   proc()
   {
   nop;
   return (proc(Y)
   {
   nop;
   return (proc(X, Y)
   {
   nop;
   return (X) + (Y);
   })(1, Y);
   })(4);
   }

Example 3:

   > verbosity = 1!;
   > procedure add(X,Y) { return X + Y; };
   > foo = bind(add,R,1);
   Warning: the given procedure has no argument named "R". The procedure is returned unchanged.
   > foo;
   proc(X, Y)
   {
   nop;
   return (X) + (Y);
   }