erl_anno(3)

NAME
erl_anno - Abstract datatype for the annotations of the Erlang Compiler.

DESCRIPTION

This module provides an abstract type that is used by the Erlang Compiler and its helper modules for holding data such as column, line number, and text. The data type is a collection of annotations as described in the following.

The Erlang Token Scanner returns tokens with a subset of the following annotations, depending on the options: column
    The column where the token begins.
location
    The line and column where the token begins, or just the line if the column is unknown.
text
    The token's text.

From this, the following annotation is derived: line
    The line where the token begins.

This module also supports the following annotations, which are used by various modules: file
    A filename.
generated
    A Boolean indicating if the abstract code is compiler-generated. The Erlang Compiler does not emit warnings for such code.
record
    A Boolean indicating if the origin of the abstract code is a record. Used by Dialyzer to assign types to tuple elements.

The functions column(), end_location(), line(), location(), and text() in the erl_scan module can be used for inspecting annotations in tokens.

The functions anno_from_term(), anno_to_term(), fold_anno(), map_anno(), mapfold_anno(), and new_anno(), in the erl_parse module can be used for manipulating annotations in abstract code.

See Also

erl_parse, erl_scan

DATA TYPES

-opaque anno()

    A collection of annotations.
anno_term() :: term().

    The term representing a collection of annotations. It is either a location/0 or a list of key-value pairs.
column() :: pos_integer().
filename() :: file:filename_all().
generated() :: boolean().
line()
location()
record_local() :: boolean().
text() :: string().

FUNCTIONS

column(Anno) -> column() | undefined when Anno :: anno().

    Returns the column of the annotations Anno.
end_location(Anno) -> location() | undefined when Anno :: anno().

    Returns the end location of the annotations Anno.

    If the end location annotation is present, its value is returned. Otherwise, if the text annotation is present, the end location is inferred from the location and the text. Finally, if there is no text, undefined is returned.
file(Anno) -> filename() | undefined when Anno :: anno().

    Returns the filename of the annotations Anno. If there is no filename, undefined is returned.
from_term(Term) -> Anno when Term :: anno_term(), Anno :: anno().

    Returns annotations with representation Term.

    See also to_term().
generated(Anno) -> generated() when Anno :: anno().

    Returns true if annotations Anno is marked as generated. The default is to return false.
is_anno(Term) -> boolean() when Term :: any().

    Returns true if Term is a collection of annotations, otherwise false.
line(Anno) -> line() when Anno :: anno().

    Returns the line of the annotations Anno.
location(Anno) -> location() when Anno :: anno().

    Returns the location of the annotations Anno. If there is no location, a zero line number is returned.
new(Location) -> anno() when Location :: location().

    Creates a new collection of annotations given a location.
set_end_location(Location, Anno) -> Anno when Location :: location(), Anno :: anno().

    Modifies the end location of the annotations Anno.
set_file(File, Anno) -> Anno when File :: filename(), Anno :: anno().

    Modifies the filename of the annotations Anno.
set_generated(Generated, Anno) -> Anno when Generated :: generated(), Anno :: anno().

    Modifies the generated marker of the annotations Anno.
set_line(Line, Anno) -> Anno when Line :: line(), Anno :: anno().

    Modifies the line of the annotations Anno.
set_location(Location, Anno) -> Anno when Location :: location(), Anno :: anno().

    Modifies the location of the annotations Anno.
set_record(Record, Anno) -> Anno when Record :: record_local(), Anno :: anno().

    Modifies the record marker of the annotations Anno.
set_text(Text, Anno) -> Anno when Text :: text(), Anno :: anno().

    Modifies the text of the annotations Anno.
text(Anno) -> text() | undefined when Anno :: anno().

    Returns the text of the annotations Anno. If there is no text, undefined is returned.
to_term(Anno) -> anno_term() when Anno :: anno().

    Returns the term representing the annotations Anno.

    See also from_term().