object

logtalk

Built-in object providing message printing, debugging, library, source file, and hacking methods.

author:
Paulo Moura
version:
1.13
date:
2017/10/18
compilation flags:
static, built_in, context_switching_calls, threaded

(no dependencies on other entities)

Public interface

Prints a message of the given kind for the specified component.

compilation flags:
static
template:
print_message(Kind,Component,Message)
mode – number of proofs:
print_message(+nonvar,+nonvar,+nonvar) – one

Print the messages tokens to the given stream, prefixing each line with the specified atom.

compilation flags:
static
template:
print_message_tokens(Stream,Prefix,Tokens)
mode – number of proofs:
print_message_tokens(@stream_or_alias,+atom,@list(nonvar)) – one

User-defined hook predicate for printing a message token (at_same_line, nl, flush, Format-Arguments, term(Term,Options), ansi(Attributes,Format,Arguments), begin(Kind,Variable), and end(Variable)).

compilation flags:
dynamic, multifile
template:
print_message_token(Stream,Prefix,Token,Tokens)
mode – number of proofs:
print_message_token(@stream_or_alias,@atom,@nonvar,@list(nonvar)) – zero_or_one

message_tokens//2

User-defined hook grammar rule for converting a message into a list of tokens (at_same_line, nl, flush, Format-Arguments, term(Term,Options), ansi(Attributes,Format,Arguments), begin(Kind,Variable), and end(Variable)).

compilation flags:
dynamic, multifile
template:
message_tokens(Message,Component)

message_prefix_stream/4

Message line prefix and output stream to be used when printing a message given its kind and component.

compilation flags:
dynamic, multifile
template:
message_prefix_stream(Kind,Component,Prefix,Stream)
mode – number of proofs:
message_prefix_stream(?nonvar,?nonvar,?atom,?stream_or_alias) – zero_or_more

message_hook/4

User-defined hook predicate for intercepting message printing calls.

compilation flags:
dynamic, multifile
template:
message_hook(Message,Kind,Component,Tokens)
mode – number of proofs:
message_hook(+nonvar,+nonvar,+nonvar,+list(nonvar)) – zero_or_one

ask_question/5

Asks a question and reads the answer until the check predicate is true.

compilation flags:
static
template:
ask_question(Kind,Component,Question,Check,Answer)
meta-predicate template:
ask_question(*,*,*,1,*)
mode – number of proofs:
ask_question(+nonvar,+nonvar,+nonvar,+callable,-term) – one

question_hook/6

User-defined hook predicate for intercepting question asking calls.

compilation flags:
dynamic, multifile
template:
question_hook(Question,Kind,Component,Tokens,Check,Answer)
meta-predicate template:
question_hook(*,*,*,*,1,*)
mode – number of proofs:
question_hook(+nonvar,+nonvar,+nonvar,+list(nonvar),+callable,-term) – zero_or_one

question_prompt_stream/4

Prompt and input stream to be used when asking a question given its kind and component.

compilation flags:
dynamic, multifile
template:
question_prompt_stream(Kind,Component,Prompt,Stream)
mode – number of proofs:
question_prompt_stream(?nonvar,?nonvar,?atom,?stream_or_alias) – zero_or_more

trace_event/2

Trace event handler. The runtime calls all trace event handlers using a failure-driven loop before calling the debug event handler.

compilation flags:
dynamic, multifile
template:
trace_event(Event,ExecutionContext)
mode – number of proofs:
trace_event(@callable,@execution_context) – zero

debug_handler_provider/1

Declares an object as the debug handler provider. There should be at most one debug handler provider loaded at any given moment.

compilation flags:
static, multifile
template:
debug_handler_provider(Provider)
mode – number of proofs:
debug_handler_provider(?object_identifier) – zero_or_one

debug_handler/2

Debug event handler. The defined events are unification events - fact(Entity,Fact,Clause,File,Line) and rule(Entity,Head,Clause,File,Line) - and goal events - top_goal(Goal,CompiledGoal) and goal(Goal,CompiledGoal).

compilation flags:
static, multifile
template:
debug_handler(Event,ExecutionContext)
mode – number of proofs:
debug_handler(?entity_identifier,?atom) – zero_or_more

expand_library_path/2

Expands a library alias or a library path into its absolute path. Uses a depth bound to prevent loops.

compilation flags:
static
template:
expand_library_path(LibraryPath,AbsolutePath)
mode – number of proofs:
expand_library_path(+atom,?atom) – zero_or_one
expand_library_path(+callable,?atom) – zero_or_one

loaded_file/1

Enumerates, by backtracking, all loaded files, returning their full paths.

compilation flags:
static
template:
loaded_file(Path)
mode – number of proofs:
loaded_file(?atom) – zero_or_more

loaded_file_property/2

Enumerates, by backtracking, all loaded file properties. Valid properties are: basename/1, directory/1, mode/1, flags/1, text_properties/1 (encoding/1 and bom/1), target/1, modified/1, parent/1, includes/1, library/1, object/1, protocol/1, and category/1.

compilation flags:
static
template:
loaded_file_property(Path,Property)
mode – number of proofs:
loaded_file_property(?atom,?compound) – zero_or_more

file_type_extension/2

Enumerates, by backtracking, all defined file type extensions. The defined types are: source, object, logtalk, prolog, and tmp. The source type returns both logtalk and prolog type extensions.

compilation flags:
static
template:
file_type_extension(Type,Extension)
mode – number of proofs:
file_type_extension(?atom,?atom) – zero_or_more

compile_aux_clauses/1

Compiles a list of auxiliary clauses. Can only be called during source file compilation, usually from term_expansion/2 or goal_expansion/2 hook predicate definitions.

compilation flags:
static
template:
compile_aux_clauses(Clauses)
mode – number of proofs:
compile_aux_clauses(@list(clause)) – one

entity_prefix/2

Converts between an entity identifier and the entity prefix that is used for its compiled code. When none of the arguments is instantiated, it returns the identifier and the prefix of the entity under compilation, if any.

compilation flags:
static
template:
entity_prefix(Entity,Prefix)
mode – number of proofs:
entity_prefix(?entity_identifier,?atom) – zero_or_one

compile_predicate_heads/4

Compiles clause heads. The heads are compiled in the context of the entity under compilation when the entity argument is not instantiated.

compilation flags:
static
template:
compile_predicate_heads(Heads,Entity,CompiledHeads,ExecutionContext)
mode – number of proofs:
compile_predicate_heads(@list(callable),?entity_identifier,-list(callable),@execution_context) – zero_or_one
compile_predicate_heads(@conjunction(callable),?entity_identifier,-conjunction(callable),@execution_context) – zero_or_one
compile_predicate_heads(@callable,?entity_identifier,-callable,@execution_context) – zero_or_one

compile_predicate_indicators/3

Compiles predicate indicators. The predicate are compiled in the context of the entity under compilation when the entity argument is not instantiated.

compilation flags:
static
template:
compile_predicate_indicators(PredicateIndicators,Entity,CompiledPredicateIndicators)
mode – number of proofs:
compile_predicate_indicators(@list(predicate_indicator),?entity_identifier,-list(predicate_indicator)) – zero_or_one
compile_predicate_indicators(@conjunction(predicate_indicator),?entity_identifier,-conjunction(predicate_indicator)) – zero_or_one
compile_predicate_indicators(@predicate_indicator,?entity_identifier,-predicate_indicator) – zero_or_one

decompile_predicate_heads/4

Decompiles clause heads. All compiled clause heads must belong to the same entity, which must be loaded.

compilation flags:
static
template:
decompile_predicate_heads(CompiledHeads,Entity,Type,Heads)
mode – number of proofs:
decompile_predicate_heads(@list(callable),-entity_identifier,-atom,-list(callable)) – zero_or_one
decompile_predicate_heads(@conjunction(callable),-entity_identifier,-atom,-conjunction(callable)) – zero_or_one
decompile_predicate_heads(@callable,-entity_identifier,-atom,-callable) – zero_or_one

decompile_predicate_indicators/4

Decompiles predicate indicators. All compiled predicate indicators must belong to the same entity, which must be loaded.

compilation flags:
static
template:
decompile_predicate_indicators(CompiledPredicateIndicators,Entity,Type,PredicateIndicators)
mode – number of proofs:
decompile_predicate_indicators(@list(predicate_indicator),-entity_identifier,-atom,-list(predicate_indicator)) – zero_or_one
decompile_predicate_indicators(@conjunction(predicate_indicator),-entity_identifier,-atom,-conjunction(predicate_indicator)) – zero_or_one
decompile_predicate_indicators(@predicate_indicator,-entity_identifier,-atom,-predicate_indicator) – zero_or_one

execution_context/7

Execution context term data. Execution context terms should be considered opaque terms subject to change without notice.

compilation flags:
static
template:
execution_context(ExecutionContext,Entity,Sender,This,Self,MetaCallContext,CoinductionStack)
mode – number of proofs:
execution_context(?nonvar,?entity_identifier,?object_identifier,?object_identifier,?object_identifier,@list(callable),@list(callable)) – zero_or_one

Protected interface

(none)

Private predicates

(none)

Operators

(none)

Remarks

Message kinds
The default set is {silent, silent(Category), banner, help, comment, comment(Category), information, information(Category), warning, warning(Category), error, error(Category), debug, debug(Category), question, question(Category)}.
Printing of silent messages
By default, silent messages are not printed. These messages are only useful when intercepted.
Printing of banner and comment messages
By default, banner and comment messages are only printed when the report flag is turned on.
Printing of help, information, and question messages
These messages are always printed by default as they provide requested output.
Printing of warning messages
By default, warning messages are not printed when the report flag is turned off.
Printing of error messages
These messages are always printed by default.
Printing of debug messages
By default, debug messages are only printed when the debug flag is turned on.
Meta messages
A meta message is a message that have another message as argument and is typically used for debugging messages. Meta messages avoid the need of defining tokenizer rules for every message but can be intercepted as any other message.
@Message meta message
By default, the message is printed as passed to the write/1 predicate followed by a newline.
Key-Value meta message
By default, the message is printed as "Key: Value" followed by a newline. The value is printed as passed to the writeq/1 predicate.
List meta message
By default, the list items are printed indented one per line. The items are preceded by a dash and printed as passed to the writeq/1 predicate.
Title::List meta message
By default, the title is printed followed by a newline and the indented list items, one per line. The items are preceded by a dash and printed as passed to the writeq/1 predicate.

See also

(none)