documents/libman/repair.tex

83 A problem variable may be associated with a tentative value.
85 previous assignments to this variable.
92 through later calls to the same predicate.  Vars can be a variable, a
98 Query the variable's tentative values.
100 place of the variables.   If a variable has no tentative value
101 a variable is returned in its place.
106 A problem variable is {\em tenable} when it does not have a
113 produces a tenable variable (note how the tentative value is printed
114 as the variable's repair-attribute), while on the other hand
119 produces an untenable variable. Note that, unlike logical assignments,
127 Succeeds if the given variable is tenable. This predicate is the link
129 a variable\footnote{
169 that variable.  A temporary variable with identical domains is substituted
175  is kept for the unified variable.  Preference is given to a tentative
176 value that would result in a tenable unified variable.
180 If a variable with a repair attribute is copied using
224 a variable in which case the system returns a conflict set handle that can
280 When a variable becomes untenable, it appears in the set of conflict
281 variable, when it becomes tenable, it disappears.
286 by changing the variable's tentative value with tent_set/2,
287 or by instantiating the variable.
309 At least one variable within a conflict constraint must be reassigned
312 by changing the variable's tentative value with tent_set/2,
313 or by instantiating the variable.
362 by (re)computing one or more of their variable's tentative values
364 the tentative value of the sum variable whenever the tentative value of one of
374 the tentative value of the Result variable.
377 variable in Expression changes.
388 This process repeats whenever the tentative value of any In-variable
396 repair variable. The programmer has therefore all the tools to write
460 As a result Z becomes a conflict variable since its tentative value (3)
483         term_variables(C, Vars),    % choose one variable in