erl_parse - The Erlang parser.
Please see following description for synopsis
erl_parse(3) Erlang Module Definition erl_parse(3)
NAME
erl_parse - The Erlang parser.
DESCRIPTION
This module is the basic Erlang parser that converts tokens into the
abstract form of either forms (that is, top-level constructs), expres-
sions, or terms. The Abstract Format is described in the ERTS User's
Guide. Notice that a token list must end with the dot token to be
acceptable to the parse functions (see the erl_scan(3)) module.
DATA TYPES
abstract_clause()
Abstract form of an Erlang clause.
abstract_expr()
Abstract form of an Erlang expression.
abstract_form()
Abstract form of an Erlang form.
abstract_type()
Abstract form of an Erlang type.
erl_parse_tree() =
abstract_clause() |
abstract_expr() |
abstract_form() |
abstract_type()
af_binelement(_)
Abstract representation of an element of a bitstring.
af_field_decl()
Abstract representation of a record field.
af_generator()
Abstract representation of a generator or a bitstring generator.
af_remote_function()>
Abstract representation of a remote function call.
error_description() = term()
error_info() =
{erl_anno:location(), module(), error_description()}
form_info() =
{eof, erl_anno:location()} |
{error, erl_scan:error_info() | error_info()} |
{warning, erl_scan:error_info() | error_info()}
Tuples {error, error_info()} and {warning, error_info()}, denot-
ing syntactically incorrect forms and warnings, and {eof,
line()}, denoting an end-of-stream encountered before a complete
form had been parsed.
token() = erl_scan:token()
EXPORTS
abstract(Data) -> AbsTerm
Types:
Data = term()
AbsTerm = abstract_expr()
Converts the Erlang data structure Data into an abstract form of
type AbsTerm. This function is the inverse of normalise/1.
erl_parse:abstract(T) is equivalent to erl_parse:abstract(T, 0).
abstract(Data, Options) -> AbsTerm
Types:
Data = term()
Options = Location | [Option]
Option =
{encoding, Encoding} | {line, Line} | {location, Loca-
tion}
Encoding = latin1 | unicode | utf8 | none | encoding_func()
Line = erl_anno:line()
Location = erl_anno:location()
AbsTerm = abstract_expr()
encoding_func() = fun((integer() >= 0) -> boolean())
Converts the Erlang data structure Data into an abstract form of
type AbsTerm.
Each node of AbsTerm is assigned an annotation, see erl_anno(3).
The annotation contains the location given by option location or
by option line. Option location overrides option line. If nei-
ther option location nor option line is given, 0 is used as
location.
Option Encoding is used for selecting which integer lists to be
considered as strings. The default is to use the encoding
returned by function epp:default_encoding/0. Value none means
that no integer lists are considered as strings. encoding_func()
is called with one integer of a list at a time; if it returns
true for every integer, the list is considered a string.
anno_from_term(Term) -> erl_parse_tree() | form_info()
Types:
Term = term()
Assumes that Term is a term with the same structure as a
erl_parse tree, but with terms, say T, where a erl_parse tree
has collections of annotations. Returns a erl_parse tree where
each term T is replaced by the value returned by
erl_anno:from_term(T). The term Term is traversed in a depth-
first, left-to-right fashion.
anno_to_term(Abstr) -> term()
Types:
Abstr = erl_parse_tree() | form_info()
Returns a term where each collection of annotations Anno of the
nodes of the erl_parse tree Abstr is replaced by the term
returned by erl_anno:to_term(Anno). The erl_parse tree is tra-
versed in a depth-first, left-to-right fashion.
fold_anno(Fun, Acc0, Abstr) -> Acc1
Types:
Fun = fun((Anno, AccIn) -> AccOut)
Anno = erl_anno:anno()
Acc0 = Acc1 = AccIn = AccOut = term()
Abstr = erl_parse_tree() | form_info()
Updates an accumulator by applying Fun on each collection of
annotations of the erl_parse tree Abstr. The first call to Fun
has AccIn as argument, the returned accumulator AccOut is passed
to the next call, and so on. The final value of the accumulator
is returned. The erl_parse tree is traversed in a depth-first,
left-to-right fashion.
format_error(ErrorDescriptor) -> Chars
Types:
ErrorDescriptor = error_description()
Chars = [char() | Chars]
Uses an ErrorDescriptor and returns a string that describes the
error. This function is usually called implicitly when an Error-
Info structure is processed (see section Error Information).
map_anno(Fun, Abstr) -> NewAbstr
Types:
Fun = fun((Anno) -> NewAnno)
Anno = NewAnno = erl_anno:anno()
Abstr = NewAbstr = erl_parse_tree() | form_info()
Modifies the erl_parse tree Abstr by applying Fun on each col-
lection of annotations of the nodes of the erl_parse tree. The
erl_parse tree is traversed in a depth-first, left-to-right
fashion.
mapfold_anno(Fun, Acc0, Abstr) -> {NewAbstr, Acc1}
Types:
Fun = fun((Anno, AccIn) -> {NewAnno, AccOut})
Anno = NewAnno = erl_anno:anno()
Acc0 = Acc1 = AccIn = AccOut = term()
Abstr = NewAbstr = erl_parse_tree() | form_info()
Modifies the erl_parse tree Abstr by applying Fun on each col-
lection of annotations of the nodes of the erl_parse tree, while
at the same time updating an accumulator. The first call to Fun
has AccIn as second argument, the returned accumulator AccOut is
passed to the next call, and so on. The modified erl_parse tree
and the final value of the accumulator are returned. The
erl_parse tree is traversed in a depth-first, left-to-right
fashion.
new_anno(Term) -> Abstr
Types:
Term = term()
Abstr = erl_parse_tree() | form_info()
Assumes that Term is a term with the same structure as a
erl_parse tree, but with locations where a erl_parse tree has
collections of annotations. Returns a erl_parse tree where each
location L is replaced by the value returned by erl_anno:new(L).
The term Term is traversed in a depth-first, left-to-right fash-
ion.
normalise(AbsTerm) -> Data
Types:
AbsTerm = abstract_expr()
Data = term()
Converts the abstract form AbsTerm of a term into a conventional
Erlang data structure (that is, the term itself). This function
is the inverse of abstract/1.
parse_exprs(Tokens) -> {ok, ExprList} | {error, ErrorInfo}
Types:
Tokens = [token()]
ExprList = [abstract_expr()]
ErrorInfo = error_info()
Parses Tokens as if it was a list of expressions. Returns one of
the following:
{ok, ExprList}:
The parsing was successful. ExprList is a list of the
abstract forms of the parsed expressions.
{error, ErrorInfo}:
An error occurred.
parse_form(Tokens) -> {ok, AbsForm} | {error, ErrorInfo}
Types:
Tokens = [token()]
AbsForm = abstract_form()
ErrorInfo = error_info()
Parses Tokens as if it was a form. Returns one of the following:
{ok, AbsForm}:
The parsing was successful. AbsForm is the abstract form of
the parsed form.
{error, ErrorInfo}:
An error occurred.
parse_term(Tokens) -> {ok, Term} | {error, ErrorInfo}
Types:
Tokens = [token()]
Term = term()
ErrorInfo = error_info()
Parses Tokens as if it was a term. Returns one of the following:
{ok, Term}:
The parsing was successful. Term is the Erlang term corre-
sponding to the token list.
{error, ErrorInfo}:
An error occurred.
tokens(AbsTerm) -> Tokens
tokens(AbsTerm, MoreTokens) -> Tokens
Types:
AbsTerm = abstract_expr()
MoreTokens = Tokens = [token()]
Generates a list of tokens representing the abstract form
AbsTerm of an expression. Optionally, MoreTokens is appended.
ERROR INFORMATION
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)
SEE ALSO
erl_anno(3), erl_scan(3), io(3), section The Abstract Format in the
ERTS User's Guide
Ericsson AB stdlib 3.17 erl_parse(3)