Boost Bind

A member of the BoostLibraries. See http://boost.org/libs/bind/bind.html. The bind library allows one to produce new functions from old functions. For example, given a binary function that multiplies integers together:

  int mul(int a, int b) {
return a * b;
  }

One could produce a new unary function that multiplies integers by 7:

  boost::bind(mul, 7, _1);

The _1 is a placeholder for the first argument to the new function. The result of this expression is a FunctorObject that behaves exactly like the unary function, lambda x: 7*x.

A notable area of application is in callbacks. One can use bind to supply context to a function, or more often, to provide an instance to a class member function reference:

  class Foo { public: void bar(int xyz) { } };
  Foo f;
  boost::bind(&Foo::bar, f, _1);

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How is this done in SmallTalk? If I have a binary block [ :a :b | a * b ], how can I transform it into a unary block by binding one of the arguments?

E.g. what would you have to add as "BlockContext?>>bindFirst" or "BlockContext?>>bindSecond" in order to achieve this? Or is there another way of doing this in SmallTalk?

-- Edouard

I would like to know the answer too. Anyone?

So, would this be sort of like partial-evaluation in a functional language, except with more control?

Doing it the normal way would probably do (can't remember exact syntax);

  binBlock := [:a :b| a * b].
  unBlock := [:a | binBlock doWith: a and: 12 ].
  orBlock := [:b | binBlock doWith: 3 and: b ].

-- Tiogshi

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