forgex_automaton_m Module

The forgex_automaton_m module contains automaton_t definition and its type-bound procedures.


Uses


Derived Types

type, public ::  automaton_t

This type contains an NFA graph, and the DFA graph that are derived from it.

Components

Type Visibility Attributes Name Initial
type(segment_t), public, allocatable :: all_segments(:)
type(dfa_graph_t), public :: dfa
type(nfa_state_set_t), public :: entry_set
integer(kind=int32), public :: initial_index = DFA_NOT_INIT
type(nfa_graph_t), public :: nfa
integer(kind=int32), public :: nfa_entry
integer(kind=int32), public :: nfa_exit
type(tree_t), public :: tree

Type-Bound Procedures

procedure, public :: construct => automaton__construct_dfa
procedure, public :: destination => automaton__destination
procedure, public :: epsilon_closure => automaton__epsilon_closure
procedure, public :: free => automaton__deallocate
procedure, public :: get_reachable => automaton__compute_reachable_state
procedure, public :: init => automaton__initialize
procedure, public :: move => automaton__move
procedure, public :: preprocess => automaton__build_nfa
procedure, public :: print => automaton__print_info
procedure, public :: print_dfa => automaton__print_dfa
procedure, public :: register_state => automaton__register_state

Functions

private pure function automaton__compute_reachable_state(self, curr_i, symbol) result(state_set)

This function calculates a set of possible NFA states from the current DFA state by the input character symbol.

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Arguments

Type IntentOptional Attributes Name
class(automaton_t), intent(in) :: self
integer(kind=int32), intent(in) :: curr_i
character(len=*), intent(in) :: symbol

Return Value type(nfa_state_set_t)

private pure function automaton__move(self, curr, symbol) result(res)

This function returns the dfa transition object, that contains the destination index and the corresponding set of transitionable NFA state.

Arguments

Type IntentOptional Attributes Name
class(automaton_t), intent(in) :: self
integer(kind=int32), intent(in) :: curr
character(len=*), intent(in) :: symbol

Return Value type(dfa_transition_t)


Subroutines

private pure subroutine automaton__build_nfa(self, tree)

Arguments

Type IntentOptional Attributes Name
class(automaton_t), intent(inout) :: self
type(tree_t), intent(in) :: tree

private pure subroutine automaton__construct_dfa(self, curr_i, dst_i, symbol)

This subroutine gets the destination index of DFA nodes from the current index with given symbol, adding a DFA node if necessary.

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Arguments

Type IntentOptional Attributes Name
class(automaton_t), intent(inout) :: self
integer(kind=int32), intent(in) :: curr_i
integer(kind=int32), intent(inout) :: dst_i
character(len=*), intent(in) :: symbol

private pure subroutine automaton__deallocate(self)

Arguments

Type IntentOptional Attributes Name
class(automaton_t), intent(inout) :: self

private pure subroutine automaton__destination(self, curr, symbol, next, next_set)

This subroutine gets the next DFA nodes index from current index and symbol, and stores the result in next and next_set.

Arguments

Type IntentOptional Attributes Name
class(automaton_t), intent(in) :: self
integer(kind=int32), intent(in) :: curr
character(len=*), intent(in) :: symbol
integer(kind=int32), intent(inout) :: next
type(nfa_state_set_t), intent(inout) :: next_set

private pure recursive subroutine automaton__epsilon_closure(self, closure, n_index)

Compute the ε-closure for a set of NFA states.

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Arguments

Type IntentOptional Attributes Name
class(automaton_t), intent(inout) :: self
type(nfa_state_set_t), intent(inout) :: closure
integer, intent(in) :: n_index

private pure subroutine automaton__initialize(self)

This subroutine reads tree and tree_top variable, constructs the NFA graph, and then initializes the DFA graph.

Arguments

Type IntentOptional Attributes Name
class(automaton_t), intent(inout) :: self

private subroutine automaton__print_dfa(self, uni)

This subroutine prints DFA states and transitions to a given unit number.

Arguments

Type IntentOptional Attributes Name
class(automaton_t), intent(in) :: self
integer(kind=int32), intent(in) :: uni

private subroutine automaton__print_info(self)

This subroutine provides the automata' summarized information.

Arguments

Type IntentOptional Attributes Name
class(automaton_t), intent(in) :: self

private pure subroutine automaton__register_state(self, state_set, res)

This subroutine takes a nfa_state_set_t type argument as input and register the set as a DFA state node in the DFA graph.

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Arguments

Type IntentOptional Attributes Name
class(automaton_t), intent(inout) :: self
type(nfa_state_set_t), intent(in) :: state_set
integer(kind=int32), intent(inout) :: res