library

Prolog files

aggregate.pl
aggregate/3	Aggregate bindings in Goal according to Template.
aggregate/4	Aggregate bindings in Goal according to Template.
aggregate_all/3	Aggregate bindings in Goal according to Template.
aggregate_all/4	Aggregate bindings in Goal according to Template.
foldall/4	Use Folder to fold V0 to V using all answers of Goal.
foreach/2	True when the conjunction of instances of Goal created from solutions for Generator is true.
free_variables/4	Find free variables in bagof/setof template.
safe_meta/2	Declare the aggregate meta-calls safe.
ansi_term.pl  -- Print decorated text to ANSI consoles
apply.pl  -- Apply predicates on a list
apply_macros.pl  -- Goal expansion rules to avoid meta-calling
apply_macros_sentinel/0	Used to detect that library(apply_macros) is loaded into the current context explicitly.
expand_phrase/2	Provide goal-expansion for PhraseGoal.
expand_phrase/4	Provide goal-expansion for PhraseGoal.
arithmetic.pl  -- Extensible arithmetic
assoc.pl  -- Binary associations
atom.pl  -- Operations on atoms
backcomp.pl  -- Backward compatibility
base32.pl
base32/2	Translates between plaintext and base32 encoded atom or string.
base32/3	Encode/decode list of character codes using base32.
base64.pl  -- Base64 encoding and decoding
broadcast.pl  -- Event service
charsio.pl
atom_to_chars/2	Convert Atom into a list of character codes.
atom_to_chars/3	Convert Atom into a difference list of character codes.
format_to_chars/3	Use format/2 to write to a list of character codes.
format_to_chars/4	Use format/2 to write to a difference list of character codes.
number_to_chars/2	Convert Atom into a list of character codes.
number_to_chars/3	Convert Number into a difference list of character codes.
open_chars_stream/2	Open Codes as an input stream.
read_from_chars/2	Read Codes into Term.
read_term_from_chars/3	Read Codes into Term.
with_output_to_chars/2	Run Goal as with once/1.
with_output_to_chars/3	Run Goal as with once/1.
with_output_to_chars/4	Same as with_output_to_chars/3 using an explicit stream.
write_to_chars/2	Write a term to a code list.
write_to_chars/3	Write a term to a code list.
check.pl
check/0	Run all consistency checks defined by checker/2.
checker/2	Register code validation routines.
list_autoload/0	Report predicates that may be auto-loaded.
list_cross_module_calls/0	List calls from one module to another using Module:Goal where the callee is not defined exported, public or multifile, i.e., where the callee should be considered private.
list_format_errors/0	List argument errors for format/2,3.
list_format_errors/1	List argument errors for format/2,3.
list_rationals/0	List rational numbers that appear in clauses.
list_rationals/1	List rational numbers that appear in clauses.
list_redefined/0	Lists predicates that are defined in the global module user as well as in a normal module; that is, predicates for which the local definition overrules the global default definition.
list_strings/0	List strings that appear in clauses.
list_strings/1	List strings that appear in clauses.
list_trivial_fails/0	List goals that trivially fail because there is no matching clause.
list_trivial_fails/1	List goals that trivially fail because there is no matching clause.
list_undefined/0	Report undefined predicates.
list_undefined/1	Report undefined predicates.
list_void_declarations/0	List predicates that have declared attributes, but no clauses.
string_predicate/1	Multifile hook to disable list_strings/0 on the given predicate.
trivial_fail_goal/1	Multifile hook that tells list_trivial_fails/0 to accept Goal as valid.
valid_string_goal/1	Multifile hook that qualifies Goal as valid for list_strings/0.
codesio.pl  -- I/O on Lists of Character Codes
coinduction.pl  -- Co-Logic Programming
csv.pl  -- Process CSV (Comma-Separated Values) data
ctypes.pl
is_digit/3	Succeeds if `C' is a digit using `Base' as base and `Weight' represents its value.
is_paren/2	True if Open is the open-parenthesis of Close.
to_lower/2	Downcase a character code.
to_upper/2	Upcase a character code.
upper_lower/2	True when U is the character code of an uppercase character and L is the character code of the corresponding lowercase character.
date.pl  -- Process dates and times
debug.pl  -- Print debug messages and test assertions
dialect.pl
expects_dialect/1	Tell Prolog all subsequent code to the end of the file or the next :- expects_dialect/1 directive is written for the indicated Dialect.
source_exports/2	True if Source exports Export.
dicts.pl
dict_fill/4	Implementation for the dicts_to_same_keys/3 OnEmpty closure that fills new cells with a copy of ValueIn.
dict_keys/2	True when Keys is an ordered set of the keys appearing in Dict.
dict_size/2	True when KeyCount is the number of keys in Dict.
dicts_join/3	Join dicts in Dicts that have the same value for Key, provided they do not have conflicting values on other keys.
dicts_join/4	Join two lists of dicts (Dicts1 and Dicts2) on Key.
dicts_same_keys/2	True if List is a list of dicts that all have the same keys and Keys is an ordered set of these keys.
dicts_same_tag/2	True when List is a list of dicts that all have the tag Tag.
dicts_slice/3	DictsOut is a list of Dicts only containing values for Keys.
dicts_to_compounds/4	True when Dicts and Compounds are lists of the same length and each element of Compounds is a compound term whose arguments represent the values associated with the corresponding keys in Keys.
dicts_to_same_keys/3	DictsOut is a copy of DictsIn, where each dict contains all keys appearing in all dicts of DictsIn.
mapdict/2	True when all dicts have the same set of keys and call(Goal, Key, V1, ...) is true for all keys in the dicts.
mapdict/3	True when all dicts have the same set of keys and call(Goal, Key, V1, ...) is true for all keys in the dicts.
mapdict/4	True when all dicts have the same set of keys and call(Goal, Key, V1, ...) is true for all keys in the dicts.
dif.pl  -- The dif/2 constraint
edinburgh.pl  -- Some traditional Edinburgh predicates
error.pl
current_encoding/1	True if Name is the name of a supported encoding.
current_type/3	True when Type is a currently defined type and Var satisfies Type of the body term Body succeeds.
domain_error/2	The argument is of the proper type, but has a value that is outside the supported values.
existence_error/2	Culprit is of the correct type and correct domain, but there is no existing (external) resource of type ObjectType that is represented by it.
existence_error/3	Culprit is of the correct type and correct domain, but there is no existing (external) resource of type ObjectType that is represented by it in the provided set.
has_type/2	True if Term satisfies Type.
instantiation_error/1	An argument is under-instantiated.
is_of_type/2	True if Term satisfies Type.
must_be/2	True if Term satisfies the type constraints for Type.
permission_error/3	It is not allowed to perform Operation on (whatever is represented by) Culprit that is of the given PermissionType (in fact, the ISO Standard is confusing and vague about these terms' meaning).
representation_error/1	A representation error indicates a limitation of the implementation.
resource_error/1	A goal cannot be completed due to lack of resources.
syntax_error/1	A text has invalid syntax.
type_error/2	Tell the user that Culprit is not of the expected ValidType.
uninstantiation_error/1	An argument is over-instantiated.
exceptions.pl
catch/4	As catch/3, only catching exceptions for which exception(ErrorType,Ball) is true.
error_term/2	Describe the formal part of error(Formal,ImplDefined) exceptions.
exception/2	If Ball is unbound, adds a delayed goal that tests the error belongs to Type when Ball is instantiated (by catch/3).
exception_term/2	Describe exceptions that are not error(Formal, _) terms.
exception_type/2	Declare all exceptions subsumed by Term to be an exception of Type.
explain.pl  -- Describe Prolog Terms
gensym.pl  -- Generate unique symbols
git.pl  -- Run GIT commands
hashtable.pl  -- Hash tables
heaps.pl
add_to_heap/4	Adds Key with priority Priority to Heap0, constructing a new heap in Heap.
delete_from_heap/4	Deletes Key from Heap0, leaving its priority in Priority and the resulting data structure in Heap.
empty_heap/1	True if Heap is an empty heap.
get_from_heap/4	Retrieves the minimum-priority pair Priority-Key from Heap0.
heap_size/2	Determines the number of elements in Heap.
heap_to_list/2	Constructs a list List of Priority-Element terms, ordered by (ascending) priority.
is_heap/1	Returns true if X is a heap.
list_to_heap/2	If List is a list of Priority-Element terms, constructs a heap out of List.
merge_heaps/3	Merge the two heaps Heap0 and Heap1 in Heap.
min_of_heap/3	Unifies Key with the minimum-priority element of Heap and Priority with its priority value.
min_of_heap/5	Gets the two minimum-priority elements from Heap.
singleton_heap/3	True if Heap is a heap with the single element Priority-Key.
help.pl  -- Text based manual
increval.pl
incr_directly_depends/2	True if Goal1 depends on Goal2 in the IDG.
incr_invalid_subgoals/1	List is a sorted list (set) of the incremental subgoals that are currently invalid.
incr_invalidate_call/1	This is the XSB name, but the manual says incr_invalidate_calls/1 and the comment with the code suggests this is misnamed.
incr_invalidate_calls/1	Invalidate all tables for subgoals of Goal as well as tables that are affected by these.
incr_is_invalid/1	True when Subgoal's table is marked as invalid.
incr_propagate_calls/1	Activate the monotonic answer propagation similarly to when a new fact is asserted for a monotonic dynamic predicate.
incr_table_update/0	Updated all invalid tables.
incr_trans_depends/2	True for each pair in the transitive closure of incr_directly_depends(G1, G2).
is_incremental_subgoal/1	This predicate non-deterministically unifies Subgoal with incrementally tabled subgoals that are currently table entries.
iostream.pl  -- Utilities to deal with streams
close_any/1	Execute the Close closure returned by open_any/5.
open_any/5	Establish a stream from Specification that should be closed using Close, which can either be called or passed to close_any/1.
lazy_lists.pl  -- Lazy list handling
listing.pl  -- List programs and pretty print clauses
lists.pl  -- List Manipulation
main.pl  -- Provide entry point for scripts
make.pl
make/0	Reload all source files that have been changed since they were loaded.
make_reload_file/1	Reload file into the proper module.
modules.pl
current_temporary_module/1	True when we are executing in the given temporary module context.
in_temporary_module/3	Run Goal on temporary loaded sources and discard the module and loaded predicates after completion.
nb_set.pl  -- Non-backtrackable sets
occurs.pl  -- Finding and counting sub-terms
operators.pl  -- Manage operators
option.pl  -- Option list processing
optparse.pl  -- command line parsing
ordsets.pl  -- Ordered set manipulation
pairs.pl
group_pairs_by_key/2	Group values with equivalent (==/2) consecutive keys.
map_list_to_pairs/3	Create a Key-Value list by mapping each element of List.
pairs_keys/2	Remove the values from a list of Key-Value pairs.
pairs_keys_values/3	True if Keys holds the keys of Pairs and Values the values.
pairs_values/2	Remove the keys from a list of Key-Value pairs.
transpose_pairs/2	Swap Key-Value to Value-Key.
persistency.pl  -- Provide persistent dynamic predicates
pio.pl  -- Pure I/O
portray_text.pl
portray_text/1	Switch portraying on or off.
set_portray_text/2	Set options for portraying.
set_portray_text/3	Set options for portraying.
pprint.pl  -- Pretty Print Prolog terms
predicate_options.pl
assert_predicate_options/4	As predicate_options(:PI, +Arg, +Options).
check_predicate_option/3	Verify predicate options at runtime.
check_predicate_options/0	Analyse loaded program for erroneous options.
check_predicate_options/1	Verify calls to predicates that have options in all clauses of the predicate indicated by PredicateIndicator.
current_option_arg/2	True when Arg of PI processes predicate options.
current_predicate_option/3	True when Arg of PI processes Option.
current_predicate_options/3	True when Options is the current active option declaration for PI on Arg.
derive_predicate_options/0	Derive new predicate option declarations.
derived_predicate_options/1	Derive predicate option declarations for a module.
derived_predicate_options/3	Derive option arguments using static analysis.
predicate_options/3	Declare that the predicate PI processes options on Arg.
retractall_predicate_options/0	Remove all dynamically (derived) predicate options.
prolog_autoload.pl
autoload_all/0	Force all necessary autoloading to be done now.
autoload_all/1	Force all necessary autoloading to be done now.
prolog_breakpoints.pl  -- Manage Prolog break-points
prolog_clause.pl
prolog_code.pl  -- Utilities for reasoning about code
prolog_codewalk.pl
prolog_program_clause/2	True when ClauseRef is a reference for clause in the program.
prolog_walk_code/1	Walk over all loaded (user) Prolog code.
subterm_pos/5	True when SubTerm is a sub term of Term, compared using Cmp, TermPosition describes the term layout of Term and SubTermPos describes the term layout of SubTerm.
prolog_colour.pl  -- Prolog syntax colouring support.
prolog_coverage.pl  -- Coverage analysis tool
prolog_debug.pl  -- User level debugging tools
prolog_format.pl  -- Analyse format specifications
prolog_metainference.pl
infer_meta_predicate/2	True when MetaSpec is a meta-predicate specifier for the predicate Head.
inferred_meta_predicate/2	True when MetaSpec is an inferred meta-predicate specification for Head.
prolog_pack.pl
pack_info/1	Print more detailed information about Pack.
pack_install/1	Install one or more packs from SpecOrList.
pack_install/2	Install one or more packs from SpecOrList.
pack_install_local/3	Install a number of packages in a local directory.
pack_list/1	Query package server and installed packages and display results.
pack_list/2	Query package server and installed packages and display results.
pack_list_installed/0	List currently installed packages and report possible dependency issues.
pack_property/2	True when Property is a property of an installed Pack.
pack_publish/2	Publish a package.
pack_rebuild/0	Rebuild possible foreign components of Pack.
pack_rebuild/1	Rebuild possible foreign components of Pack.
pack_remove/1	Remove the indicated package.
pack_remove/2	Remove the indicated package.
pack_search/1	Query package server and installed packages and display results.
pack_upgrade/1	Upgrade Pack.
pack_url_file/2	True if File is a unique id for the referenced pack and version.
prolog_profile.pl  -- Execution profiler
prolog_source.pl  -- Examine Prolog source-files
prolog_stack.pl  -- Examine the Prolog stack
prolog_versions.pl  -- Demand specific (Prolog) versions
prolog_xref.pl  -- Prolog cross-referencer data collection
pure_input.pl
lazy_list_character_count/3	True when CharCount is the current character count in the Lazy list.
lazy_list_location/3	Determine current (error) location in a lazy list.
phrase_from_file/2	Process the content of File using the DCG rule Grammar.
phrase_from_file/3	As phrase_from_file/2, providing additional Options.
phrase_from_stream/2	Run Grammer against the character codes on Stream.
stream_to_lazy_list/2	Create a lazy list representing the character codes in Stream.
syntax_error/3	Throw the syntax error Error at the current location of the input.
quasi_quotations.pl  -- Define Quasi Quotation syntax
quintus.pl  -- Quintus compatibility
random.pl  -- Random numbers
rbtrees.pl
is_rbtree/1	True if Term is a valid Red-Black tree.
list_to_rbtree/2	Tree is the red-black tree corresponding to the mapping in List, which should be a list of Key-Value pairs.
ord_list_to_rbtree/2	Tree is the red-black tree corresponding to the mapping in list List, which should be a list of Key-Value pairs.
rb_apply/4	If the value associated with key Key is Val0 in Tree, and if call(G,Val0,ValF) holds, then NewTree differs from Tree only in that Key is associated with value ValF in tree NewTree.
rb_clone/3	`Clone' the red-back tree TreeIn into a new tree TreeOut with the same keys as the original but with all values set to unbound values.
rb_del_max/4	Delete the largest element from the tree Tree, returning the key Key, the value Val associated with the key and a new tree NewTree.
rb_del_min/4	Delete the least element from the tree Tree, returning the key Key, the value Val associated with the key and a new tree NewTree.
rb_delete/3	Delete element with key Key from the tree Tree, returning the value Val associated with the key and a new tree NewTree.
rb_delete/4	Same as rb_delete(Tree, Key, NewTree), but also unifies Val with the value associated with Key in Tree.
rb_empty/1	Succeeds if Tree is an empty Red-Black tree.
rb_fold/4	Fold the given predicate over all the key-value pairs in Tree, starting with initial state State0 and returning the final state State.
rb_in/3	True when Key-Value is a key-value pair in red-black tree Tree.
rb_insert/4	Add an element with key Key and Value to the tree Tree creating a new red-black tree NewTree.
rb_insert_new/4	Add a new element with key Key and Value to the tree Tree creating a new red-black tree NewTree.
rb_keys/2	Keys is unified with an ordered list of all keys in the Red-Black tree Tree.
rb_lookup/3	True when Value is associated with Key in the Red-Black tree Tree.
rb_map/2	True if call(Goal, Value) is true for all nodes in T.
rb_map/3	For all nodes Key in the tree Tree, if the value associated with key Key is Val0 in tree Tree, and if call(G,Val0,ValF) holds, then the value associated with Key in NewTree is ValF.
rb_max/3	Key is the maximal key in Tree, and is associated with Val.
rb_min/3	Key is the minimum key in Tree, and is associated with Val.
rb_new/1	Create a new Red-Black tree Tree.
rb_next/4	Next is the next element after Key in Tree, and is associated with Val.
rb_partial_map/4	For all nodes Key in Keys, if the value associated with key Key is Val0 in tree Tree, and if call(G,Val0,ValF) holds, then the value associated with Key in NewTree is ValF, otherwise it is the value associated with the key in Tree.
rb_previous/4	Previous is the previous element after Key in Tree, and is associated with Val.
rb_size/2	Size is the number of elements in Tree.
rb_update/4	Tree NewTree is tree Tree, but with value for Key associated with NewVal.
rb_update/5	Same as rb_update(Tree, Key, NewVal, NewTree) but also unifies OldVal with the value associated with Key in Tree.
rb_visit/2	Pairs is an infix visit of tree Tree, where each element of Pairs is of the form Key-Value.
readln.pl
readutil.pl
read_file_to_codes/3	Read the file Spec into a list of Codes.
read_file_to_string/3	Read the file Spec into a the string String.
read_file_to_terms/3	Read the file Spec into a list of terms.
read_line_to_codes/2	Read the next line of input from Stream.
read_line_to_codes/3	Difference-list version to read an input line to a list of character codes.
read_line_to_string/2	Read the next line from Stream into String.
read_stream_to_codes/2	Read input from Stream to a list of character codes.
read_stream_to_codes/3	Read input from Stream to a list of character codes.
record.pl  -- Access compound arguments by name
rwlocks.pl  -- Read/write locks
sandbox.pl  -- Sandboxed Prolog code
settings.pl  -- Setting management
shlib.pl
compat_arch/2	User definable hook to establish if Arch1 is compatible with Arch2 when running a shared object.
current_foreign_library/2	Query currently loaded shared libraries.
load_foreign_library/1	Load a shared object or DLL.
load_foreign_library/2	Load a shared object or DLL.
reload_foreign_libraries/0	Reload all foreign libraries loaded (after restore of a state created using qsave_program/2.
unload_foreign_library/1	Unload a shared object or DLL.
unload_foreign_library/2	Unload a shared object or DLL.
use_foreign_library/1	Load and install a foreign library as load_foreign_library/1,2 and register the installation using initialization/2 with the option now.
use_foreign_library/2	Load and install a foreign library as load_foreign_library/1,2 and register the installation using initialization/2 with the option now.
solution_sequences.pl
call_nth/2	True when Goal succeeded for the Nth time.
distinct/1	True if Goal is true and no previous solution of Goal bound Witness to the same value.
distinct/2	True if Goal is true and no previous solution of Goal bound Witness to the same value.
group_by/4	Group bindings of Template that have the same value for By.
limit/2	Limit the number of solutions.
offset/2	Ignore the first Count solutions.
order_by/2	Order solutions according to Spec.
reduced/1	Similar to distinct/1, but does not guarantee unique results in return for using a limited amount of memory.
reduced/3	Similar to distinct/1, but does not guarantee unique results in return for using a limited amount of memory.
sort.pl
locale_sort/2	Sort a list of atoms using the current locale.
predsort/3	Sorts similar to sort/2, but determines the order of two terms by calling Compare(-Delta, +E1, +E2).
statistics.pl
call_time/2	Call Goal as call/1, unifying Time with a dict that provides information on the resource usage.
call_time/3	Call Goal as call/1, unifying Time with a dict that provides information on the resource usage.
statistics/0	Print information about resource usage using print_message/2.
statistics/1	Stats is a dict representing the same information as statistics/0.
thread_statistics/2	Obtain statistical information about a single thread.
time/1	Execute Goal, reporting statistics to the user.
strings.pl  -- String utilities
system.pl  -- System utilities
tables.pl
abolish_table_call/1	Same as abolish_table_subgoals/1.
abolish_table_call/2	Same as abolish_table_subgoals/1.
abolish_table_pred/1	Invalidates all tabled subgoals for the predicate denoted by the predicate or term indicator Pred.
abolish_table_subgoals/2	Behaves as abolish_table_subgoals/1, but allows the default table_gc_action to be over-ridden with a flag, which can be either abolish_tables_transitively or abolish_tables_singly.
get_call/3	True when Trie is an answer trie for a variant of CallTerm.
get_calls/3	True when Trie is an answer trie for a variant that unifies with CallTerm and Skeleton is the answer skeleton.
get_residual/2	True if CallTerm appears in a table and has DelayList.
get_returns/2	True when Return is an answer template for the AnswerTrie.
get_returns/3	True when Return is an answer template for the AnswerTrie and the answer is represented by the trie node NodeID.
get_returns_and_dls/3	True when Return appears in AnswerTrie with the given DelayLists.
get_returns_and_tvs/3	Identical to get_returns/2, but also obtains the truth value of a given answer, setting TruthValue to t if the answer is unconditional and to u if it is conditional.
get_returns_for_call/2	True if AnswerTerm appears in the tables for the variant CallTerm.
set_pil_off/0	Dummy predicates for XSB compatibility.
set_pil_on/0	Dummy predicates for XSB compatibility.
t not/1	Tabled negation.
tfindall/3	This predicate emerged in XSB in an attempt to provide a safer alternative to findall/3.
terms.pl  -- Term manipulation
thread.pl  -- High level thread primitives
call_in_thread/2	Run Goal as an interrupt in the context of Thread.
concurrent/3	Run Goals in parallel using N threads.
concurrent_and/2	Concurrent version of (Generator,Test).
concurrent_and/3	Concurrent version of (Generator,Test).
concurrent_forall/2	True when Action is true for all solutions of Generate.
concurrent_forall/3	True when Action is true for all solutions of Generate.
concurrent_maplist/2	Concurrent version of maplist/2.
concurrent_maplist/3	Concurrent version of maplist/2.
concurrent_maplist/4	Concurrent version of maplist/2.
first_solution/3	Try alternative solvers concurrently, returning the first answer.
thread_pool.pl  -- Resource bounded thread management
threadutil.pl  -- Interactive thread utilities
attach_console/0	Create a new console and make the standard Prolog streams point to it.
attach_console/1	Create a new console and make the standard Prolog streams point to it.
join_threads/0	Join all terminated threads.
tbacktrace/1	Print a backtrace for Thread to the stream user_error of the calling thread.
tbacktrace/2	Print a backtrace for Thread to the stream user_error of the calling thread.
tdebug/0	Enable debug-mode, trapping the graphical debugger on reaching spy-points or errors.
tdebug/1	Enable debug-mode, trapping the graphical debugger on reaching spy-points or errors.
thread_has_console/0	True when the calling thread has an attached console.
threads/0	List currently known threads with their status.
tnodebug/0	Disable debug-mode in all threads or the specified Thread.
tnodebug/1	Disable debug-mode in all threads or the specified Thread.
tprofile/1	Profile the operation of Thread until the user hits a key.
tspy/1	Trap the graphical debugger on reaching Spec in the specified or any thread.
tspy/2	Trap the graphical debugger on reaching Spec in the specified or any thread.
with_stopped_threads/2	Stop all threads except the caller while running once(Goal).
tty.pl
menu/3	Show a menu.
tty_clear/0	Clear the display.
tty_flash/0	Give visual signal if possible, otherwise beep.
ugraphs.pl
add_edges/3	Unify NewGraph with a new graph obtained by adding the list of Edges to Graph.
add_vertices/3	Unify NewGraph with a new graph obtained by adding the list of Vertices to Graph.
complement/2	UGraphOut is a ugraph with an edge between all vertices that are not connected in UGraphIn and all edges from UGraphIn removed.
compose/3	Compose NewGraph by connecting the drains of LeftGraph to the sources of RightGraph.
connect_ugraph/3	Adds Start as an additional vertex that is connected to all vertices in UGraphIn.
del_edges/3	Unify NewGraph with a new graph obtained by removing the list of Edges from Graph.
del_vertices/3	Unify NewGraph with a new graph obtained by deleting the list of Vertices and all the edges that start from or go to a vertex in Vertices to the Graph.
edges/2	Unify Edges with all edges appearing in Graph.
neighbors/3	Neigbours is a sorted list of the neighbours of Vertex in Graph.
neighbours/3	Neigbours is a sorted list of the neighbours of Vertex in Graph.
reachable/3	True when Vertices is an ordered set of vertices reachable in UGraph, including Vertex.
top_sort/2	Sort vertices topologically.
transitive_closure/2	Generate the graph Closure as the transitive closure of Graph.
transpose_ugraph/2	Unify NewGraph with a new graph obtained from Graph by replacing all edges of the form V1-V2 by edges of the form V2-V1.
ugraph_layers/2	Sort vertices topologically.
ugraph_union/3	NewGraph is the union of Graph1 and Graph2.
vertices/2	Unify Vertices with all vertices appearing in Graph.
vertices_edges_to_ugraph/3	Create a UGraph from Vertices and Edges.
url.pl  -- Analysing and constructing URL
utf8.pl  -- UTF-8 encoding/decoding on lists of character codes.
varnumbers.pl  -- Utilities for numbered terms
wfs.pl  -- Well Founded Semantics interface
when.pl  -- Conditional coroutining
www_browser.pl  -- Open a URL in the users browser
yall.pl  -- Lambda expressions
zip.pl  -- Access resource ZIP archives