NAME

SYNOPSIS

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

DATA TYPES

filesexpr() = {Sexpr,Line}

This is the format returned by lfe_io:parse_file/1 and is used by the compiler to give better error information.

EXPORTS

Read an s-expr from the standard input (IoDevice) with a prompt (Prompt). Note that this is not line-oriented in that it stops as soon as it has consumed enough characters.

read_line([[IoDevice,] Prompt]) -> {ok,Sexpr} | {error,ErrorInfo}

Read an s-expr from the standard input (IoDevice) with a prompt (Prompt). Note that this is line-oriented in that it reads whole lines discarding left-over characters in the last line.

read_string(String) -> {ok,Sexpr} | {error,ErrorInfo}

Read an s-expr from String.

print([IoDevice,] Sexpr) -> ok

Print the s-expr Sexpr to the standard output (IoDevice).

print1(Sexpr) -> DeepCharList

Return the list of characters which represent the s-expr Sexpr.

prettyprint1(Sexpr) -> DeepCharList

prettyprint1(Sexpr, Depth) -> DeepCharList

prettyprint1(Sexpr, Depth, Indentation) -> DeepCharList

prettyprint1(Sexpr, Depth, Indentation, LineLength) -> DeepCharList

Return the lost of characters which represents the prettyprinted s-expr Sexpr. Assume we start at indentation Indentation or 0.

format([IoDevice,] Format, Args) -> ok

fwrite([IoDevice,] Format, Args) -> ok

format1(Format, Args) -> DeepCharList

fwrite1(Format, Args) -> DeepCharList

Print formatted output. The following commands are valid in the format string:

•

~w, ~W - print LFE terms

•

~p, ~P - prettyprint LFE terms

•

~s - print a string

•

~e, ~f, ~g - print floats

•

~b, ~B - based integers

•

~x, ~X - based integers with a prefix

•

~+, ~# - based integers in vanilla erlang format

•

~c, ~n, ~i

Currently they behave as for vanilla erlang except that ~w, ~W, ~p, ~P print the terms as LFE sexprs.

read_file(FileName) -> {ok,[Sexpr]} | {error,ErrorInfo}

Read the file Filename returning a list of s-exprs (as it should be).

parse_file(FileName) -> {ok,[FileSexpr]} | {error,ErrorInfo}

where

FileSexpr = filesexpr()

    

Read the file Filename returning a list of pairs containing s-expr and line number of the start of the s-expr.

scan_sexpr(Cont, Chars [,Line]) -> {done,Ret,RestChars}|{more,Cont1}

This is a re-entrant call which scans tokens from the input and returns a parsed sepxr. If there are enough characters to parse a sexpr or it detects and error then it returns {done,...} otherwise it returns {more,Cont} where Cont is used in the next call to scan_sexpr with more characters to try and parse a sexpr. This is continued until a sexpr has been parsed. Cont is initially [].

It is not designed to be called directly by an application but used through the i/o system where it can typically be called in an application by:

io:request(In, {get_until,unicode,Prompt,Module,scan_sexpr,[Line]})

ERROR INFORMATION

{ErrorLine,Module,ErrorDescriptor}

A string describing the error is obtained with the following call:

apply(Module, format_error, ErrorDescriptor)

    

AUTHORS