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module lang::sdf2::filters::IndirectPreferAvoid

rascal-0.40.16

Usage​

import lang::sdf2::filters::IndirectPreferAvoid;

Dependencies​

import ParseTree;
import Set;

function isPreferred​

default bool isPreferred(Tree _)

bool isPreferred(appl(prod(_,_,{\tag("prefer"()),*_}),_))

bool isPreferred(appl(prod(Symbol _,[Symbol _],set[Attr] _), [Tree arg]))

function isAvoided​

default bool isAvoided(Tree _)

bool isAvoided(appl(prod(_,_,{\tag("avoid"()),*_}),_))

bool isAvoided(appl(prod(Symbol _,[Symbol _],set[Attr] _), [Tree arg]))

function indirectPreferAvoidFilter​

Import his module if you want prefer/avoid filtering enabled for your grammar. Use @prefer and @avoid to label alternatives.

&T <:Tree indirectPreferAvoidFilter(amb(set[&T <:Tree] alternatives))