Module nfatools

Functions

[hide private]

is_token(s)

symbols(lst)

collect_symbols(nfas)

keywords(used_symbols)

terminals(used_symbols, keywords)

reduced_nfa(nfas, start)
Computes a nfa while skipping any skippable labels.

last_set(nfas, reachables)
The EndTrans(A) = { A_t1, ..., A_tk } is the set of "end transitions" of A i.e.

first_set(nfas, r)

expanded_transitions(nfas, r)

all_selections(nfas, r, full=True)

cyclefree_traces(nfas, nonterminals)

span_traces(nfas, nonterminals)

flatten_list(lst)

reachables(nfas)

terminal_ancestors(reachables)

lexnfa2regex(nfa, pseudo_token)
Constructs a set of regular expressions from an nfa :

Function Details

[hide private]

last_set(nfas, reachables)

The EndTrans(A) = { A_t1, ..., A_tk } is the set of "end transitions" of A i.e. those transitions that contain (None,'-',A). The LastSet(A) of A is defined recursively by EndTrans(A) together with the EndTrans of each element in EndTrans(A). Often LastSet(A) is just {None}. In those cases we do not care.

This function computes the LastSets of all nodes in the NFA set.

lexnfa2regex(nfa, pseudo_token)

Constructs a set of regular expressions from an nfa :

   If NFA = {L1:T1, ..., Ln:Tn} is given we try to construct a regex for each label L
   that matches the same string as an NFALexer would match following the standard parsing
   routine.