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
arithmetic_expression_value/2	True when Result unifies with the arithmetic result of evaluating Expression.
arithmetic_function/1	Declare a predicate as an arithmetic function.
assoc.pl  -- Binary associations
atom.pl
identifier_parts/2	Parts is a list of atoms that make up Identifier.
join_identifier_parts/3	Join parts of an identifier according to Style.
restyle_identifier/3	Restyle an identifier by extracting the alnum substrings and joining them together according to Style.
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  -- I/O on Lists of Character Codes
check.pl  -- Consistency checking
codesio.pl  -- I/O on Lists of Character Codes
coinduction.pl  -- Co-Logic Programming
csv.pl
csv/3	Prolog DCG to `read/write' CSV data.
csv/4	Prolog DCG to `read/write' CSV data.
csv_options/2	Compiled is the compiled representation of the CSV processing options as they may be passed into csv//2, etc.
csv_read_file/2	Read a CSV file into a list of rows.
csv_read_file/3	Read a CSV file into a list of rows.
csv_read_file_row/3	True when Row is a row in File.
csv_read_row/3	Read the next CSV record from Stream and unify the result with Row.
csv_read_stream/3	Read CSV data from Stream.
csv_write_file/2	Write a list of Prolog terms to a CSV file.
csv_write_file/3	Write a list of Prolog terms to a CSV file.
csv_write_stream/3	Write the rows in Data to Stream.
ctypes.pl  -- Character code classification
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 utilities
dif.pl  -- The dif/2 constraint
edinburgh.pl  -- Some traditional Edinburgh predicates
edit.pl
edit/0	Edit associated or script file.
edit/1	Edit indicated object.
edit_command/2	This predicate should specify the shell-command called to invoke the user's editor.
locate/2	Locate object from the specified location.
locate/3
select_location/3
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  -- Exception classification
explain.pl
explain/1	Give an explanation on Term.
explain/2	True when Explanation is an explanation of Term.
fastrw.pl
fast_read/1	The next term is read from current standard input and is unified with Term.
fast_write/1	Output Term in a way that fast_read/1 and fast_read/2 will be able to read it back.
fast_write_to_string/3	Perform a fast-write to the difference-slist String\Tail.
files.pl
gensym.pl
gensym/2	Generate <Base>1, <Base>2, etc atoms on each subsequent call.
reset_gensym/0	Reset gensym for all registered keys.
reset_gensym/1	Restart generation of identifiers from Base at <Base>1.
git.pl  -- Run GIT commands
hashtable.pl
ht_del/3	Delete Key-Value from HT.
ht_gen/3	True when Key-Value is in HT.
ht_get/3	True when Key is in HT and associated with Value.
ht_is_hashtable/1	True when HT is a hash table.
ht_keys/2	True when Keys is an ordered set of all keys in HT.
ht_new/1	Create a new hash table.
ht_pairs/2	True when Pairs and HT represent the same association.
ht_put/3	Add a Key-Value to HT.
ht_put/5	Add Key-Value to HT.
ht_put_new/3	As ht_put/3, but fails if Key is already in HT instead of updating the associated value.
ht_size/2	True when Size is the number of key-value pairs in HT.
ht_update/4	True when HT holds Key-Old before and Key-New after this call.
heaps.pl  -- heaps/priority queues
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.
intercept.pl  -- Intercept and signal interface
iostream.pl  -- Utilities to deal with streams
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  -- Reload modified source files
modules.pl  -- Module utility predicates
nb_set.pl  -- Non-backtrackable sets
occurs.pl
contains_term/2	Succeeds if Sub is contained in Term (=, deterministically).
contains_var/2	Succeeds if Sub is contained in Term (==, deterministically).
free_of_term/2	Succeeds of Sub does not unify to any subterm of Term.
free_of_var/2	Succeeds of Sub is not equal (==) to any subterm of Term.
occurrences_of_term/3	Count the number of SubTerms in Term that unify with SubTerm.
occurrences_of_var/3	Count the number of SubTerms in Term that are equal to SubTerm.
sub_term/2	Generates (on backtracking) all subterms of Term.
sub_term_shared_variables/3	If Sub is a sub term of Term, Vars is bound to the list of variables in Sub that also appear outside Sub in Term.
sub_var/2	Generates (on backtracking) all subterms (==) of Term.
operators.pl
pop_operators/0	Revert all changes to the operator table realised since the last push_operators/1.
pop_operators/1	Reset operators as pushed by push_operators/2.
push_op/3	As op/3, but this call must appear between push_operators/1 and pop_operators/0.
push_operators/1	Installs the operators from New, where New is a list of op(Prec, Type, :Name).
push_operators/2	Installs the operators from New, where New is a list of op(Prec, Type, :Name).
option.pl  -- Option list processing
optparse.pl  -- command line parsing
ordsets.pl  -- Ordered set manipulation
pairs.pl  -- Operations on key-value lists
persistency.pl
current_persistent_predicate/1	True if PI is a predicate that provides access to the persistent database DB.
db_assert/1	Assert Term into the database and record it for persistency.
db_attach/2	Use File as persistent database for the calling module.
db_attached/1	True if the context module attached to the persistent database File.
db_detach/0	Detach persistency from the calling module and delete all persistent clauses from the Prolog database.
db_retract/1	Retract terms from the database one-by-one.
db_retractall/1	Retract all matching facts and do the same in the database.
db_sync/1	Synchronise database with the associated file.
db_sync_all/1	Sync all registered databases.
persistent/1	Declare dynamic database terms.
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  -- Access and analyse 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
breakpoint_property/2	True when Property is a property of the breakpoint Id.
delete_breakpoint/1	Delete breakpoint with given Id.
set_breakpoint/4	Put a breakpoint at the indicated source-location.
set_breakpoint/5	Put a breakpoint at the indicated source-location.
set_breakpoint_condition/2	Set a condition for of the breakpoint with given Id.
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_config.pl  -- Provide configuration information
prolog_coverage.pl
cov_load_data/2	Reload coverage data from File.
cov_property/1	True when coverage analysis satisfies Property.
cov_reset/0	Discard all collected coverage data.
cov_save_data/2	Save the coverage information to File.
coverage/1	As call(Goal), collecting coverage information while Goal is running.
coverage/2	Collect and optionally report coverage by Goal.
report_hook/2	This hook is called after the data collection.
show_coverage/1	Show collected coverage data.
prolog_debug.pl
debug_control_hook/1	Allow user-hooks in the Prolog debugger interaction.
debugging/0	Report current status of the debugger.
debugging_hook/1	Multifile hook that is called as forall(debugging_hook(DebugMode), true) and that may be used to extend the information printed from other debugging libraries.
exception_hook/5	Trap exceptions and consider whether or not to start the tracer.
nospy/1	Set/clear spy-points.
nospyall/0	Set/clear spy-points.
notrap/1	Install a trap on error(Formal, Context) exceptions that unify.
spy/1	Set/clear spy-points.
trap/1	Install a trap on error(Formal, Context) exceptions that unify.
trap_alias/2	Define short hands for commonly used exceptions.
prolog_format.pl  -- Analyse format specifications
prolog_history.pl
prolog_history/1	Execute Action on the history.
prolog_jiti.pl  -- Just In Time Indexing (JITI) utilities
prolog_metainference.pl  -- Infer meta-predicate properties
prolog_pack.pl  -- A package manager for Prolog
prolog_profile.pl
profile/1	Run once(Goal) under the execution profiler.
profile/2	Run once(Goal) under the execution profiler.
profile_data/1	Gather all relevant data from profiler.
profile_procedure_data/2	Collect data for Pred.
show_profile/1	Display last collected profiling data.
prolog_source.pl
quasi_quotation_syntax/2	True when the quasi quotation syntax Syntax can be loaded from Library.
xref_close_source/2	Called by prolog_close_source/1 to close a source previously opened by the hook prolog:xref_open_source/2.
xref_open_source/2	Hook to open an xref SourceID.
directory_source_files/3	True when Files is a sorted list of Prolog source files in Dir.
file_alias_path/2	True if file Alias points to Dir.
file_name_on_path/2	True if OnPath a description of File based on the file search path.
load_quasi_quotation_syntax/2	Import quasi quotation syntax Syntax from Path into the module specified by the first argument.
path_segments_atom/2	Translate between a path represented as a/b/c and an atom representing the same path.
prolog_canonical_source/2	Given a user-specification of a source, generate a unique and indexable identifier for it.
prolog_close_source/1	Close a stream opened using prolog_open_source/2.
prolog_file_directives/3	True when Directives is a list of directives that appear in the source file File.
prolog_open_source/2	Open source with given canonical id (see prolog_canonical_source/2) and remove the #!
prolog_read_source_term/4	Read a term from a Prolog source-file.
read_source_term_at_location/3	Try to read a Prolog term form an arbitrary location inside a file.
requires_library/2	known expansion hooks.
valid_term_position/2	Check that a Term has an appropriate TermPos layout.
prolog_stack.pl  -- Examine the Prolog stack
prolog_trace.pl
list_tracing/0	List predicates we are currently tracing.
notraceall/0	Remove all trace points.
trace/1	Print passes through ports of specified predicates.
trace/2	Print passes through ports of specified predicates.
tracing/2	True if Spec is traced using Ports.
prolog_versions.pl  -- Demand specific (Prolog) versions
prolog_wrap.pl
current_predicate_wrapper/4	True if Head is wrapped with Body.
unwrap_predicate/2	Remove the outermost wrapper whose name unifies with Name.
wrap_predicate/4	Wrap the predicate referenced by Head using Body.
prolog_xref.pl  -- Prolog cross-referencer data collection
pure_input.pl  -- Pure Input from files and streams
quasi_quotations.pl
phrase_from_quasi_quotation/2	Process the quasi quotation using the DCG Grammar.
quasi_quotation_syntax/1	Declare the predicate SyntaxName/4 to implement the the quasi quote syntax SyntaxName.
quasi_quotation_syntax_error/1	Report syntax_error(Error) using the current location in the quasi quoted input parser.
with_quasi_quotation_input/3	Process the quasi-quoted Content using Stream parsed by Goal.
quintus.pl  -- Quintus compatibility
random.pl
getrand/1	Query/set the state of the random generator.
maybe/0	Succeed/fail with equal probability (variant of maybe/1).
maybe/1	Succeed with probability P, fail with probability 1-P.
maybe/2	Succeed with probability K/N (variant of maybe/1).
random/1	Binds R to a new random float in the open interval (0.0,1.0).
random/3	Generate a random integer or float in a range.
random_between/3	Binds R to a random integer in [L,U] (i.e., including both L and U).
random_member/2	X is a random member of List.
random_numlist/4	Unify List with an ascending list of integers between L and U (inclusive).
random_perm2/4	Does X=A,Y=B or X=B,Y=A with equal probability.
random_permutation/2	Permutation is a random permutation of List.
random_select/3	Randomly select or insert an element.
random_subseq/3	Selects a random subsequence Subseq of List, with Complement containing all elements of List that were not selected.
randseq/3	S is a list of K unique random integers in the range 1..N.
randset/3	S is a sorted list of K unique random integers in the range 1..N.
setrand/1	Query/set the state of the random generator.
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.
readutil.pl  -- Read utilities
record.pl
current_record/2	True if Name is the name of a record defined in the module associated with Term and Term is the user-provided record declaration.
current_record_predicate/2	True if PI is the predicate indicator for an access predicate to Record.
record/1	Define access predicates for a compound-term.
rwlocks.pl  -- Read/write locks
sandbox.pl
sandbox_allowed_directive/1	Throws an exception if G is not considered a safe directive.
sandbox_allowed_expansion/1	Throws an exception if G is not considered a safe expansion goal.
sandbox_allowed_goal/1	Throw an exception if it is not safe to call G.
format_calls/3	Find ~@ calls from Format and Args.
safe_call/1	Call Goal if it complies with the sandboxing rules.
safe_directive/1	Hook to declare additional directives as safe.
safe_global_variable/1	Declare the given global variable safe to write to.
safe_goal/1	True if calling Goal provides no security risc.
safe_meta/2	Hook.
safe_primitive/1	True if Goal is safe to call (i.e., cannot access dangerous system-resources and cannot upset other parts of the Prolog process).
safe_prolog_flag/2	True if it is safe to set the flag Flag to Value.
settings.pl  -- Setting management
shell.pl  -- Elementary shell commands
shlib.pl  -- Utility library for loading foreign objects (DLLs, shared objects)
solution_sequences.pl  -- Modify solution sequences
sort.pl
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.
streams.pl  -- Manage Prolog streams
strings.pl
dedent_lines/3	Remove shared indentation for all lines in a string.
indent_lines/3	Add Prefix to the beginning of lines in In.
indent_lines/4	Similar to indent_lines/3, but only adds Prefix to lines for which call(Filter, Line) succeeds.
interpolate_string/4	Establish a string from a template by replacing patterns.
string/4	Implements the quasi quotation syntax string.
string_lines/2	True when String represents Lines.
system.pl
lock_predicate/1	Transform a predicate into a system predicate.
system_mode/1	Switch the system into system or user mode.
system_module/0	Any predicate defined after this declaraction uptil the end of the file will become a system predicate.
unlock_predicate/1	Transform a system predicate into a normal system predicate.
tables.pl  -- XSB interface to tables
terms.pl  -- Term manipulation
thread.pl
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).
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
max_var_number/3	True when Max is the max of Start and the highest numbered $VAR(N) term.
numbervars/1	Number variables in Term using $VAR(N).
varnumbers/2	Inverse of numbervars/1.
varnumbers/3	Inverse of numbervars/3.
varnumbers_names/3	If Term is a term with numbered and named variables using the reserved term '$VAR'(X), Copy is a copy of Term where each '$VAR'(X) is consistently replaced by a fresh variable and Bindings is a list X = Var, relating the X terms with the variable it is mapped to.
wfs.pl  -- Well Founded Semantics interface
when.pl  -- Conditional coroutining
writef.pl  -- Old-style formatted write
www_browser.pl
expand_url_path/2	Expand URL specifications similar to absolute_file_name/3.
known_browser/2	True if browser FileBaseName has a remote protocol compatible to Compatible.
www_open_url/1	Open URL in running version of the users' browser or start a new browser.
yall.pl  -- Lambda expressions
zip.pl  -- Access resource ZIP archives