erl_anno

Abstract datatype for the annotations of the Erlang Compiler.

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.

Types

anno()

A collection of annotations.

anno_term() = term()

The term representing a collection of annotations. It is either a location() or a list of key-value pairs.

column() = integer() >= 1

line() = integer() >= 0

location() = line() | {line(), column()}

text() = string()

Functions

column(Anno) -> column() | undefined

  • column() = integer() >= 1

Returns the column of the annotations Anno.

end_location(Anno) -> location() | undefined

Returns the end location of the text of the annotations Anno. If there is no text, undefined is returned.

file(Anno) -> filename() | undefined

Returns the filename of the annotations Anno. If there is no filename, undefined is returned.

from_term(Term) -> Anno

Returns annotations with representation Term.

See also to_term().

generated(Anno) -> generated()

  • generated() = boolean()

Returns true if annotations Anno is marked as generated. The default is to return false.

is_anno(Term) -> boolean()

  • Term = any()

Returns true if Term is a collection of annotations, otherwise false.

line(Anno) -> line()

  • line() = integer() >= 0

Returns the line of the annotations Anno.

location(Anno) -> location()

Returns the location of the annotations Anno.

new(Location) -> anno()

Creates a new collection of annotations given a location.

set_file(File, Anno) -> Anno

Modifies the filename of the annotations Anno.

set_generated(Generated, Anno) -> Anno

  • generated() = boolean()

Modifies the generated marker of the annotations Anno.

set_line(Line, Anno) -> Anno

  • line() = integer() >= 0

Modifies the line of the annotations Anno.

set_location(Location, Anno) -> Anno

Modifies the location of the annotations Anno.

set_record(Record, Anno) -> Anno

  • record() = boolean()

Modifies the record marker of the annotations Anno.

set_text(Text, Anno) -> Anno

  • text() = string()

Modifies the text of the annotations Anno.

text(Anno) -> text() | undefined

  • text() = string()

Returns the text of the annotations Anno. If there is no text, undefined is returned.

to_term(Anno) -> anno_term()

Returns the term representing the annotations Anno.

See also from_term().

See Also

erl_parse(3), erl_scan(3)