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module analysis::grammars::dramb::Util

rascal-0.40.17
drambiguity-0.3.5

Usage​

import analysis::grammars::dramb::Util;

Source code​

http://github.com/cwi-swat/drambiguity/blob/main/src/analysis/grammars/dramb/Util.rsc

Dependencies​

import ParseTree;
import Grammar;
import Node;
import lang::rascal::grammar::definition::Regular;
import lang::rascal::format::Grammar;
import util::Maybe;
import util::Math;
import String;

function delabel​

Symbol delabel(label(str _, Symbol s))

Symbol delabel(conditional(Symbol s, set[Condition] _))

default Symbol delabel(Symbol s)

function cast​

&T cast(type[&T] c, value x)

function symbol​

Symbol symbol(appl(prod(label(str _, Symbol s), _ , _), _))

Symbol symbol(appl(regular(Symbol s), _))

Symbol symbol(amb({Tree a, *Tree _}))

Symbol symbol(char(int i))

default Symbol symbol(appl(prod(Symbol s, _ , _), _))

function reparse​

Tree reparse(type[Tree] grammar, Tree t)

Tree reparse(type[Tree] grammar, str x)

Tree reparse(type[Tree] grammar, Symbol s, str x)

function saveParse​

Maybe[Tree] saveParse(type[Tree] grammar, str input)

function isChar​

bool isChar(char(_))

default bool isChar(Tree _)

function isLayout​

bool isLayout(appl(prod(layouts(_),_,_),_))

bool isLayout(appl(prod(label(_, layouts(_)),_,_),_))

default bool isLayout(Tree _)

function isLiteral​

bool isLiteral(appl(prod(lit(_),_,_),_))

default bool isLiteral(Tree _)

function completeLocs​

Tree completeLocs(Tree t:amb({Tree u,*_}))

Tree completeLocs(Tree t:amb({Tree u,*_}))

default Tree completeLocs(Tree t)

tuple[Tree, int] completeLocs(Tree t, loc parent, int offset)

function sorts​

set[Symbol] sorts(type[&T <: Tree] grammar)

function ambNestingDepth​

Compute the depth of amb clusters as they are nested on top of each other.

int ambNestingDepth(appl(_, list[Tree] args))

int ambNestingDepth(amb(set[Tree] alts))

int ambNestingDepth(cycle(_,_))

int ambNestingDepth(char(_))

This function uses @memo to avoid exponential running times. If ambiguity clusters are nested, then the size of the forest in memory is polynomial, even if an exponential number of trees are represented. The algorithm counts on the structural equality of nested clusters as they are reached via different paths of the parent clusters. If the number of elements in each cluster is bounded to 2 then this count will be linear in the size of the cluster in memory, which means its a polynomial in the length of the represented input string. Grammars with very long productions produce (much) longer running times.

function format​

str format(Symbol s)

str format(Production p)

str format(type[Tree] grammar)