erl_pp(3erl) [linux man page]

erl_pp(3erl)						     Erlang Module Definition						      erl_pp(3erl)

NAME

       erl_pp - The Erlang Pretty Printer

DESCRIPTION

       The functions in this module are used to generate aesthetically attractive representations of abstract forms, which are suitable for print-
       ing. All functions return (possibly deep) lists of characters and generate an error if the form is wrong.

       All functions can have an optional argument which specifies a hook that is called if an attempt is made to print an unknown form.

EXPORTS

       form(Form) -> DeepCharList
       form(Form, HookFunction) -> DeepCharList

	      Types  Form = term()
		     HookFunction = see separate description below.
		     DeepCharList = [char()|DeepCharList]

	      Pretty prints a Form which is an abstract form of a type which is returned by erl_parse:parse_form .

       attribute(Attribute) -> DeepCharList
       attribute(Attribute, HookFunction) -> DeepCharList

	      Types  Attribute = term()
		     HookFunction = see separate description below.
		     DeepCharList = [char()|DeepCharList]

	      The same as form , but only for the attribute Attribute .

       function(Function) -> DeepCharList
       function(Function, HookFunction) -> DeepCharList

	      Types  Function = term()
		     HookFunction = see separate description below.
		     DeepCharList = [char()|DeepCharList]

	      The same as form , but only for the function Function .

       guard(Guard) -> DeepCharList
       guard(Guard, HookFunction) -> DeepCharList

	      Types  Form = term()
		     HookFunction = see separate description below.
		     DeepCharList = [char()|DeepCharList]

	      The same as form , but only for the guard test Guard .

       exprs(Expressions) -> DeepCharList
       exprs(Expressions, HookFunction) -> DeepCharList
       exprs(Expressions, Indent, HookFunction) -> DeepCharList

	      Types  Expressions = term()
		     HookFunction = see separate description below.
		     Indent = integer()
		     DeepCharList = [char()|DeepCharList]

	      The same as form , but only for the sequence of expressions in Expressions .

       expr(Expression) -> DeepCharList
       expr(Expression, HookFunction) -> DeepCharList
       expr(Expression, Indent, HookFunction) -> DeepCharList
       expr(Expression, Indent, Precedence, HookFunction) ->-> DeepCharList

	      Types  Expression = term()
		     HookFunction = see separate description below.
		     Indent = integer()
		     Precedence =
		     DeepCharList = [char()|DeepCharList]

	      This function prints one expression. It is useful for implementing hooks (see below).

UNKNOWN EXPRESSION HOOKS

       The optional argument HookFunction , shown in the functions described above, defines a function which is called when an unknown form occurs
       where there should be a valid expression. It can have the following formats:

	 Function :
	   The hook function is called by:

	 Function(Expr,
		  CurrentIndentation,
		  CurrentPrecedence,
		  HookFunction)

	 none :
	   There is no hook function

       The called hook function should return a (possibly deep) list of characters. expr/4 is useful in a hook.

       If CurrentIndentation is negative, there will be no line breaks and only a space is used as a separator.

BUGS

       It should be possible to have hook functions for unknown forms at places other than expressions.

SEE ALSO

       io(3erl) , erl_parse(3erl) , erl_eval(3erl)

Ericsson AB							   stdlib 1.17.3						      erl_pp(3erl)

epp_dodger(3erl)					     Erlang Module Definition						  epp_dodger(3erl)

NAME

       epp_dodger - epp_dodger - bypasses the Erlang preprocessor.

DESCRIPTION

       epp_dodger - bypasses the Erlang preprocessor.

       This module tokenises and parses most Erlang source code without expanding preprocessor directives and macro applications, as long as these
       are syntactically "well-behaved". Because the normal parse trees of the erl_parse module cannot represent these things (normally, they  are
       expanded  by  the Erlang preprocessor epp(3erl) before the parser sees them), an extended syntax tree is created, using the erl_syntax mod-
       ule.

DATA TYPES

	 errorinfo() = {ErrorLine::integer(), Module::atom(), Descriptor::term()} :

	   This is a so-called Erlang I/O ErrorInfo structure; see the io(3erl) module for details.

EXPORTS

       parse(Dev::IODevice) -> {ok, Forms} | {error, errorinfo()}

	      Equivalent to parse(IODevice, 1) .

       parse(Dev::IODevice, L::StartLine) -> {ok, Forms} | {error, errorinfo()}

	      Types  IODevice = pid()
		     StartLine = integer()
		     Forms = [syntaxTree() (see module erl_syntax)]

	      Equivalent to parse(IODevice, StartLine, []) .

	      See also: parse/1 .

       parse(Dev::IODevice, L0::StartLine, Options) -> {ok, Forms} | {error, errorinfo()}

	      Types  IODevice = pid()
		     StartLine = integer()
		     Options = [term()]
		     Forms = [syntaxTree() (see module erl_syntax)]

	      Reads and parses program text from an I/O stream. Characters are read from IODevice until end-of-file; apart from this,  the  behav-
	      iour is the same as for parse_file/2 . StartLine is the initial line number, which should be a positive integer.

	      See also: parse/2 , parse_file/2 , parse_form/2 , quick_parse/3 .

       parse_file(File) -> {ok, Forms} | {error, errorinfo()}

	      Types  File = filename() (see module file)
		     Forms = [syntaxTree() (see module erl_syntax)]

	      Equivalent to parse_file(File, []) .

       parse_file(File, Options) -> {ok, Forms} | {error, errorinfo()}

	      Types  File = filename() (see module file)
		     Options = [term()]
		     Forms = [syntaxTree() (see module erl_syntax)]

	      Reads  and  parses  a  file. If successful, {ok, Forms} is returned, where Forms is a list of abstract syntax trees representing the
	      "program forms" of the file (cf. erl_syntax:is_form/1 ). Otherwise, {error, errorinfo()} is returned, typically if  the  file  could
	      not  be  opened.	Note  that parse errors show up as error markers in the returned list of forms; they do not cause this function to
	      fail or return {error, errorinfo()} .

	      Options:

		{no_fail, boolean()} :
		  If true , this makes epp_dodger replace any program forms that could not be  parsed  with  nodes  of	type  text  (see  erl_syn-
		  tax:text/1 ), representing the raw token sequence of the form, instead of reporting a parse error. The default value is false .

		{clever, boolean()} :
		  If  set to true , this makes epp_dodger try to repair the source code as it seems fit, in certain cases where parsing would oth-
		  erwise fail. Currently, it inserts ++ -operators between string literals and	macros	where  it  looks  like	concatenation  was
		  intended. The default value is false .

	      See also: parse/2 , quick_parse_file/1 , erl_syntax:is_form/1 .

       parse_form(Dev::IODevice, L0::StartLine) -> {ok, Form, LineNo} | {eof, LineNo} | {error, errorinfo(), LineNo}

	      Types  IODevice = pid()
		     StartLine = integer()
		     Form = syntaxTree() (see module erl_syntax)
		     LineNo = integer()

	      Equivalent to parse_form(IODevice, StartLine, []) .

	      See also: quick_parse_form/2 .

       parse_form(Dev::IODevice, L0::StartLine, Options) -> {ok, Form, LineNo} | {eof, LineNo} | {error, errorinfo(), LineNo}

	      Types  IODevice = pid()
		     StartLine = integer()
		     Options = [term()]
		     Form = syntaxTree() (see module erl_syntax)
		     LineNo = integer()

	      Reads and parses a single program form from an I/O stream. Characters are read from IODevice until an end-of-form marker is found (a
	      period character followed by whitespace), or until end-of-file; apart from this, the behaviour is  similar  to  that  of	parse/3  ,
	      except  that  the  return  values also contain the final line number given that StartLine is the initial line number, and that {eof,
	      LineNo} may be returned.

	      See also: parse/3 , parse_form/2 , quick_parse_form/3 .

       quick_parse(Dev::IODevice) -> {ok, Forms} | {error, errorinfo()}

	      Equivalent to quick_parse(IODevice, 1) .

       quick_parse(Dev::IODevice, L::StartLine) -> {ok, Forms} | {error, errorinfo()}

	      Types  IODevice = pid()
		     StartLine = integer()
		     Forms = [syntaxTree() (see module erl_syntax)]

	      Equivalent to quick_parse(IODevice, StartLine, []) .

	      See also: quick_parse/1 .

       quick_parse(Dev::IODevice, L0::StartLine, Options) -> {ok, Forms} | {error, errorinfo()}

	      Types  IODevice = pid()
		     StartLine = integer()
		     Options = [term()]
		     Forms = [syntaxTree() (see module erl_syntax)]

	      Similar to parse/3 , but does a more quick-and-dirty processing of the code. See quick_parse_file/2 for details.

	      See also: parse/3 , quick_parse/2 , quick_parse_file/2 , quick_parse_form/2 .

       quick_parse_file(File) -> {ok, Forms} | {error, errorinfo()}

	      Types  File = filename() (see module file)
		     Forms = [syntaxTree() (see module erl_syntax)]

	      Equivalent to quick_parse_file(File, []) .

       quick_parse_file(File, Options) -> {ok, Forms} | {error, errorinfo()}

	      Types  File = filename() (see module file)
		     Options = [term()]
		     Forms = [syntaxTree() (see module erl_syntax)]

	      Similar to parse_file/2 , but does a more quick-and-dirty processing of the code. Macro definitions and  other  preprocessor  direc-
	      tives  are  discarded,  and  all	macro calls are replaced with atoms. This is useful when only the main structure of the code is of
	      interest, and not the details. Furthermore, the quick-parse method can usually handle more strange cases than the normal, more exact
	      parsing.

	      Options: see parse_file/2 . Note however that for quick_parse_file/2 , the option no_fail is true by default.

	      See also: parse_file/2 , quick_parse/2 .

       quick_parse_form(Dev::IODevice, L0::StartLine) -> {ok, Form, LineNo} | {eof, LineNo} | {error, errorinfo(), LineNo}

	      Types  IODevice = pid()
		     StartLine = integer()
		     Form = syntaxTree() (see module erl_syntax) | none
		     LineNo = integer()

	      Equivalent to quick_parse_form(IODevice, StartLine, []) .

	      See also: parse_form/2 .

       quick_parse_form(Dev::IODevice, L0::StartLine, Options) -> {ok, Form, LineNo} | {eof, LineNo} | {error, errorinfo(), LineNo}

	      Types  IODevice = pid()
		     StartLine = integer()
		     Options = [term()]
		     Form = syntaxTree() (see module erl_syntax)
		     LineNo = integer()

	      Similar to parse_form/3 , but does a more quick-and-dirty processing of the code. See quick_parse_file/2 for details.

	      See also: parse/3 , parse_form/3 , quick_parse_form/2 .

       tokens_to_string(Tokens::[term()]) -> string()

	      Generates a string corresponding to the given token sequence. The string can be re-tokenized to yield the same token list again.

AUTHORS

       Richard Carlsson <richardc@it.uu.se >

								syntax_tools 1.6.7						  epp_dodger(3erl)