epp
An Erlang code preprocessor.
The Erlang code preprocessor includes functions that are used by the compile
module to preprocess macros and include files before the parsing takes place.
The Erlang source file encoding is selected by a comment in one of the first two lines of the source file. The first string matching the regular expression coding\s*[:=]\s*([-a-zA-Z0-9])+
selects the encoding. If the matching string is not a valid encoding, it is ignored. The valid encodings are Latin-1
and UTF-8
, where the case of the characters can be chosen freely.
Examples:
%% coding: utf-8
%% For this file we have chosen encoding = Latin-1
%% -*- coding: latin-1 -*-
macros() = [atom() | {atom(), term()}]
epp_handle() = pid()
Handle to the epp
server.
source_encoding() = latin1 | utf8
Closes the preprocessing of a file.
source_encoding()
Returns the default encoding of Erlang source files.
Returns a string representation of an encoding. The string is recognized by read_encoding/1,2
, read_encoding_from_binary/1,2
, and set_encoding/1,2
as a valid encoding.
io_lib:chars()
Takes an ErrorDescriptor
and returns a string that describes the error or warning. This function is usually called implicitly when processing an ErrorInfo
structure (see section Error Information
).
Opens a file for preprocessing.
If extra
is specified in Options
, the return value is {ok, Epp, Extra}
instead of {ok, Epp}
.
Equivalent to epp:open([{name, FileName}, {includes, IncludePath}])
.
Equivalent to epp:open([{name, FileName}, {includes, IncludePath}, {macros, PredefMacros}])
.
Returns the next Erlang form from the opened Erlang source file. Tuple {eof, Line}
is returned at the end of the file. The first form corresponds to an implicit attribute -file(File,1).
, where File
is the file name.
Preprocesses and parses an Erlang source file. Notice that tuple {eof, Line}
returned at the end of the file is included as a "form".
If extra
is specified in Options
, the return value is {ok, [Form], Extra}
instead of {ok, [Form]}
.
Equivalent to epp:parse_file(FileName, [{includes, IncludePath}, {macros, PredefMacros}])
.
source_encoding()
| nonesource_encoding()
| noneRead the encoding
from a file. Returns the read encoding, or none
if no valid encoding is found.
Option in_comment_only
is true
by default, which is correct for Erlang source files. If set to false
, the encoding string does not necessarily have to occur in a comment.
source_encoding()
| nonesource_encoding()
| noneRead the encoding
from a binary. Returns the read encoding, or none
if no valid encoding is found.
Option in_comment_only
is true
by default, which is correct for Erlang source files. If set to false
, the encoding string does not necessarily have to occur in a comment.
source_encoding()
| noneReads the encoding
from an I/O device and sets the encoding of the device accordingly. The position of the I/O device referenced by File
is not affected. If no valid encoding can be read from the I/O device, the encoding of the I/O device is set to the default encoding.
Returns the read encoding, or none
if no valid encoding is found.
source_encoding()
| noneReads the encoding
from an I/O device and sets the encoding of the device accordingly. The position of the I/O device referenced by File
is not affected. If no valid encoding can be read from the I/O device, the encoding of the I/O device is set to the encoding
specified by Default
.
Returns the read encoding, or none
if no valid encoding is found.
ErrorInfo
is the standard ErrorInfo
structure that is returned from all I/O modules. The format is as follows:
{ErrorLine, Module, ErrorDescriptor}
A string describing the error is obtained with the following call:
Module:format_error(ErrorDescriptor)
© 2010–2017 Ericsson AB
Licensed under the Apache License, Version 2.0.