Right Hand Sides

Syntax

RightHandSide =
     "=" Path.

Evaluation

The evaluation of a rest = Q at a level m proceeds as follows. The path Q is evaluated at the level 0. If the result obtained is a failure $fail(k), then the whole construct returns the failure $fail(m+1), which is so strong as to overcome all surrounding fences that are not neutralized by cuts.

     Env,0,St |- Q => Ge,St'
     -------------------------
     Env,m,St |- = Q => Ge,St'


     Env,0,St |- Q => $fail(k),St'
     ---------------------------------
     Env,m,St |- = Q => $fail(m+1),St'


     Env,0,St |- Q => $error(Ge),St'
     ---------------------------------
     Env,m,St |- = Q => $error(Ge),St'
Related concepts
Paths