Dictionary

value restriction en · NOUN

Meanings

1. (qualifier:type theory, uncountable) In a functional language, inference of a polymorphic type only for syntactic values (values that can be evaluated at compile time) to ensure that a program is type-safe.
   • It has been found empirically that eta expansion usually suffices for dealing with the value restriction. 2007, Geoffrey Smith, Notes on SML97's Value Restriction:
   • A typical example is an expression returning always the empty list. It should be given the polymorphic type α list, but this is not possible under the value restriction if the expression has to be evaluated. 2004, Jacques Garrigue, Relaxing the Value Restriction: