Topic: constraints  topics > computer science > data > Group:
type checking  data type  abstract data type consistency testing
database consistency and reliability declarative vs. procedural
representation dependency analysis error safe systems
implementation of user interfaces range checking run-time
assertions user interface tool kits   A constraint is a
predicate on dynamic behavior. For example, setting the width of
a column to 50% constrains the column to half the width of the
table.  Constraints are a declarative description. They are
useful for type declaration. A constraint solver takes a system
of constraints and finds a satisfying assignment of free
variables. Constraint solvers may be difficult to use. (cbb
4/06)  Subtopic: constraints as types up  Quote: a robust
library expresses constraints as types, reports errors relative
to user, and does not cause application errors [»fricA4_2000]
Subtopic: constraints up  Quote: a one-way constraint determines
the value of a variable from an expression; e.