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.

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() >= 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 representation Term.

              See also to_term().

       generated(Anno) -> generated()

              Types:

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

              Returns true if annotations Anno is 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, otherwise false.

       line(Anno) -> line()

              Types:

                 Anno = anno()
                 line() = integer() >= 0

              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() >= 0

              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_parse(3erl), erl_scan(3erl)