NAME

       erl_anno -
           Abstract Datatype for the Annotations of the Erlang Compiler

DESCRIPTION

       This module implements 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 unknown.

         text:
           The token's text.

       From the above the following annotation is derived:

         line:
           The line where the token begins.

       Furthermore, the following annotations are supported by this module, and 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 map_anno(), fold_anno(), mapfold_anno(), new_anno(),  anno_from_term(),  and
       anno_to_term()  in  the  erl_parse  module  can  be  used  for manipulating annotations in
       abstract code.

DATA 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()

              To be changed to a non-negative integer in Erlang/OTP 19.0.

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

       text() = string()

EXPORTS

       column(Anno) -> column() | undefined

              Types:

                 Anno = anno()
                 column() = integer() >= 1

              Returns the column of the annotations Anno.

       end_location(Anno) -> location() | undefined

              Types:

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

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

       file(Anno) -> filename() | undefined

              Types:

                 Anno = anno()
                 filename() = file:filename_all()

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

       from_term(Term) -> Anno

              Types:

                 Term = anno_term()
                 Anno = anno()

              Returns annotations with the representation Term.

              See also to_term().

       generated(Anno) -> generated()

              Types:

                 Anno = anno()
                 generated() = boolean()

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

       is_anno(Term) -> boolean()

              Types:

                 Term = any()

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

       line(Anno) -> line()

              Types:

                 Anno = anno()
                 line() = integer()

              Returns the line of the annotations Anno.

       location(Anno) -> location()

              Types:

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

              Returns the location of the annotations Anno.

       new(Location) -> anno()

              Types:

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

              Creates a new collection of annotations given a location.

       set_file(File, Anno) -> Anno

              Types:

                 File = filename()
                 Anno = anno()
                 filename() = file:filename_all()

              Modifies the filename of the annotations Anno.

       set_generated(Generated, Anno) -> Anno

              Types:

                 Generated = generated()
                 Anno = anno()
                 generated() = boolean()

              Modifies the generated marker of the annotations Anno.

       set_line(Line, Anno) -> Anno

              Types:

                 Line = line()
                 Anno = anno()
                 line() = integer()

              Modifies the line of the annotations Anno.

       set_location(Location, Anno) -> Anno

              Types:

                 Location = location()
                 Anno = anno()
                 location() = line() | {line(), column()}

              Modifies the location of the annotations Anno.

       set_record(Record, Anno) -> Anno

              Types:

                 Record = record()
                 Anno = anno()
                 record() = boolean()

              Modifies the record marker of the annotations Anno.

       set_text(Text, Anno) -> Anno

              Types:

                 Text = text()
                 Anno = anno()
                 text() = string()

              Modifies the text of the annotations Anno.

       text(Anno) -> text() | undefined

              Types:

                 Anno = anno()
                 text() = string()

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

       to_term(Anno) -> anno_term()

              Types:

                 Anno = anno()

              Returns the term representing the annotations Anno.

              See also from_term().

SEE ALSO

       erl_scan(3erl), erl_parse(3erl)