Specs

build_text(FormatList) -> chars() when FormatList :: [char() | format_spec()].

For details, see scan_format/2.

Specs

char_list(Term) -> boolean() when Term :: term().

Returns true if Term is a flat list of characters in the Unicode range, otherwise false.

Specs

deep_char_list(Term) -> boolean() when Term :: term().

Returns true if Term is a, possibly deep, list of characters in the Unicode range, otherwise false.

Specs

deep_latin1_char_list(Term) -> boolean() when Term :: term().

Returns true if Term is a, possibly deep, list of characters in the ISO Latin-1 range, otherwise false.

Specs

format(Format, Data) -> chars() when Format :: io:format(), Data :: [term()].

Returns a character list that represents Data formatted in accordance with Format. For a detailed description of the available formatting options, see io:fwrite/1,2,3. If the format string or argument list contains an error, a fault is generated.

If and only if the Unicode translation modifier is used in the format string (that is, ~ts or ~tc), the resulting list can contain characters beyond the ISO Latin-1 character range (that is, numbers > 255). If so, the result is still an ordinary Erlang string(), and can well be used in any context where Unicode data is allowed.

Specs

format(Format, Data, Options) -> chars()
          when
              Format :: io:format(),
              Data :: [term()],
              Options :: [Option],
              Option :: {chars_limit, CharsLimit},
              CharsLimit :: chars_limit().

Returns a character list that represents Data formatted in accordance with Format in the same way as fwrite/2 and format/2, but takes an extra argument, a list of options.

Valid option:

{chars_limit, CharsLimit}

A soft limit on the number of characters returned. When the number of characters is reached, remaining structures are replaced by "...". CharsLimit defaults to -1, which means no limit on the number of characters returned.

Specs

fread(Format, String) -> Result
         when
             Format :: string(),
             String :: string(),
             Result ::
                 {ok, InputList :: [fread_item()], LeftOverChars :: string()} |
                 {more,
                  RestFormat :: string(),
                  Nchars :: non_neg_integer(),
                  InputStack :: chars()} |
                 {error, {fread, What :: fread_error()}}.

Tries to read String in accordance with the control sequences in Format. For a detailed description of the available formatting options, see io:fread/3. It is assumed that String contains whole lines.

The function returns:

{ok, InputList, LeftOverChars}

The string was read. InputList is the list of successfully matched and read items, and LeftOverChars are the input characters not used.

{more, RestFormat, Nchars, InputStack}

The string was read, but more input is needed to complete the original format string. RestFormat is the remaining format string, Nchars is the number of characters scanned, and InputStack is the reversed list of inputs matched up to that point.

{error, What}

The read operation failed and parameter What gives a hint about the error.

Example:

3> io_lib:fread("~f~f~f", "15.6 17.3e-6 24.5").
{ok,[15.6,1.73e-5,24.5],[]}

Specs

fread(Continuation, CharSpec, Format) -> Return
         when
             Continuation :: continuation() | [],
             CharSpec :: string() | eof,
             Format :: string(),
             Return ::
                 {more, Continuation1 :: continuation()} |
                 {done, Result, LeftOverChars :: string()},
             Result ::
                 {ok, InputList :: [fread_item()]} | eof | {error, {fread, What :: fread_error()}}.

This is the re-entrant formatted reader. The continuation of the first call to the functions must be []. For a complete description of how the re-entrant input scheme works, see Armstrong, Virding, Williams: 'Concurrent Programming in Erlang', Chapter 13.

The function returns:

{done, Result, LeftOverChars}

The input is complete. The result is one of the following:

{ok, InputList}

The string was read. InputList is the list of successfully matched and read items, and LeftOverChars are the remaining characters.

eof

End of file was encountered. LeftOverChars are the input characters not used.

{error, What}

An error occurred and parameter What gives a hint about the error.

{more, Continuation}

More data is required to build a term. Continuation must be passed to fread/3 when more data becomes available.

Specs

fwrite(Format, Data) -> chars() when Format :: io:format(), Data :: [term()].

Specs

fwrite(Format, Data, Options) -> chars()
          when
              Format :: io:format(),
              Data :: [term()],
              Options :: [Option],
              Option :: {chars_limit, CharsLimit},
              CharsLimit :: chars_limit().

Specs

indentation(String, StartIndent) -> integer() when String :: string(), StartIndent :: integer().

Returns the indentation if String has been printed, starting at StartIndent.

Specs

latin1_char_list(Term) -> boolean() when Term :: term().

Returns true if Term is a flat list of characters in the ISO Latin-1 range, otherwise false.

Specs

nl() -> string().

Returns a character list that represents a new line character.

Specs

print(Term) -> chars() when Term :: term().

Returns a list of characters that represents Term, but breaks representations longer than one line into many lines and indents each line sensibly. Also tries to detect and output lists of printable characters as strings.

• Column is the starting column; defaults to 1.
• LineLength is the maximum line length; defaults to 80.
• Depth is the maximum print depth; defaults to -1, which means no limitation.

Specs

print(Term, Column, LineLength, Depth) -> chars()
         when
             Term :: term(),
             Column :: non_neg_integer(),
             LineLength :: non_neg_integer(),
             Depth :: depth().

Specs

printable_latin1_list(Term) -> boolean() when Term :: term().

Returns true if Term is a flat list of printable ISO Latin-1 characters, otherwise false.

Specs

printable_list(Term) -> boolean() when Term :: term().

Returns true if Term is a flat list of printable characters, otherwise false.

What is a printable character in this case is determined by startup flag +pc to the Erlang VM; see io:printable_range/0 and erl(1).

Specs

printable_unicode_list(Term) -> boolean() when Term :: term().

Returns true if Term is a flat list of printable Unicode characters, otherwise false.

Specs

scan_format(Format, Data) -> FormatList
               when
                   Format :: io:format(), Data :: [term()], FormatList :: [char() | format_spec()].

Returns a list corresponding to the specified format string, where control sequences have been replaced with corresponding tuples. This list can be passed to:

• build_text/1 to have the same effect as format(Format, Args)

• unscan_format/1 to get the corresponding pair of Format and Args (with every * and corresponding argument expanded to numeric values)

A typical use of this function is to replace unbounded-size control sequences like ~w and ~p with the depth-limited variants ~W and ~P before formatting to text in, for example, a logger.

Specs

unscan_format(FormatList) -> {Format, Data}
                 when
                     FormatList :: [char() | format_spec()],
                     Format :: io:format(),
                     Data :: [term()].

For details, see scan_format/2.

Specs

write(Term) -> chars() when Term :: term().

Returns a character list that represents Term. Option Depth controls the depth of the structures written. When the specified depth is reached, everything below this level is replaced by "...". Depth defaults to -1, which means no limitation. Option CharsLimit puts a soft limit on the number of characters returned. When the number of characters is reached, remaining structures are replaced by "...". CharsLimit defaults to -1, which means no limit on the number of characters returned.

Example:

1> lists:flatten(io_lib:write({1,[2],[3],[4,5],6,7,8,9})).
"{1,[2],[3],[4,5],6,7,8,9}"
2> lists:flatten(io_lib:write({1,[2],[3],[4,5],6,7,8,9}, 5)).
"{1,[2],[3],[...],...}"
3> lists:flatten(io_lib:write({[1,2,3],[4,5],6,7,8,9}, [{chars_limit,20}])).
"{[1,2|...],[4|...],...}"

Specs

write(Term, Depth) -> chars() when Term :: term(), Depth :: depth();
     (Term, Options) -> chars()
         when
             Term :: term(),
             Options :: [Option],
             Option ::
                 {chars_limit, CharsLimit} | {depth, Depth} | {encoding, latin1 | utf8 | unicode},
             CharsLimit :: chars_limit(),
             Depth :: depth().

Specs

write_atom(Atom) -> chars() when Atom :: atom().

Returns the list of characters needed to print atom Atom.

Specs

write_atom_as_latin1(Atom) -> latin1_string() when Atom :: atom().

Returns the list of characters needed to print atom Atom. Non-Latin-1 characters are escaped.

Specs

write_char(Char) -> chars() when Char :: char().

Returns the list of characters needed to print a character constant in the Unicode character set.

Specs

write_char_as_latin1(Char) -> latin1_string() when Char :: char().

Returns the list of characters needed to print a character constant in the Unicode character set. Non-Latin-1 characters are escaped.

Specs

write_latin1_char(Latin1Char) -> latin1_string() when Latin1Char :: unicode:latin1_char().

Returns the list of characters needed to print a character constant in the ISO Latin-1 character set.

Specs

write_latin1_string(Latin1String) -> latin1_string() when Latin1String :: latin1_string().

Returns the list of characters needed to print Latin1String as a string.

Specs

write_string(String) -> chars() when String :: string().

Returns the list of characters needed to print String as a string.

Specs

write_string_as_latin1(String) -> latin1_string() when String :: string().

Returns the list of characters needed to print String as a string. Non-Latin-1 characters are escaped.