View Source cerl (compiler v8.4.1)
Core Erlang abstract syntax trees.
This module defines an abstract data type for representing Core Erlang source code as syntax trees.
A recommended starting point for the first-time user is the documentation of the
function type/1.
NOTES:
This module deals with the composition and decomposition of syntactic entities (as opposed to semantic ones); its purpose is to hide all direct references to the data structures used to represent these entities. With few exceptions, the functions in this module perform no semantic interpretation of their inputs, and in general, the user is assumed to pass type-correct arguments - if this is not done, the effects are not defined.
Currently, the internal data structure used is the same as the record-based data structures used traditionally in the Beam compiler.
The internal representations of abstract syntax trees are subject to change
without notice, and should not be documented outside this module. Furthermore,
we do not give any guarantees on how an abstract syntax tree may or may not be
represented, with the following exceptions: no syntax tree is represented by a
single atom, such as none, by a list constructor [X | Y], or by the empty
list []. This can be relied on when writing functions that operate on syntax
trees.
Summary
Functions
Creates a syntax tree corresponding to an Erlang term. Term must be a literal
term, i.e., one that can be represented as a source code literal. Thus, it may
not contain a process identifier, port, reference, binary or function value as a
subterm.
Appends Annotations to the list of user annotations of Node.
Returns the pattern subtree of an abstract pattern alias.
Returns the variable subtree of an abstract pattern alias.
See also: abstract/1.
See also: c_alias/2.
See also: c_apply/2.
See also: c_atom/1.
See also: c_binary/1.
Equivalent to ann_c_bitstr(As, Value, Size, abstract(1), Type, Flags).
See also: c_call/3.
See also: c_case/2.
See also: c_catch/1.
See also: c_char/1.
See also: c_cons/2.
See also: c_cons_skel/2.
See also: c_float/1.
Equivalent to ann_c_var(As, {Atom, Arity}).
See also: c_fun/2.
See also: c_int/1.
See also: c_let/3.
See also: c_letrec/2.
See also: c_nil/0.
See also: c_primop/2.
Equivalent to ann_c_receive(As, Clauses, c_atom(infinity), c_atom(true)).
See also: c_seq/2.
See also: c_string/1.
See also: c_tuple/1.
See also: c_tuple_skel/1.
See also: c_values/1.
See also: c_var/1.
See also: make_data/2.
See also: make_data_skel/2.
Equivalent to ann_make_list(As, List, none).
See also: ann_make_list/2, make_list/2.
Creates a syntax tree with the given annotations, type and subtrees. See
make_tree/2 for details.
Returns the list of argument subtrees of an abstract function application.
Returns the number of argument subtrees of an abstract function application.
Returns the operator subtree of an abstract function application.
Returns the literal string represented by an abstract atom. This always includes surrounding single-quote characters.
Returns the printname of an abstract atom.
Returns the value represented by an abstract atom.
Returns the list of segment subtrees of an abstract binary-template.
Returns the total size in bits of an abstract bit-string template. If the size
field is an integer literal, the result is the product of the size and unit
values; if the size field is the atom literal all, the atom all is returned.
If the size is not a literal, the atom any is returned.
Returns the flags subtree of an abstract bit-string template.
Returns the size subtree of an abstract bit-string template.
Returns the type subtree of an abstract bit-string template.
Returns the unit subtree of an abstract bit-string template.
Returns the value subtree of an abstract bit-string template.
Creates an abstract pattern alias. The result represents
"*Variable* = *Pattern*".
Creates an abstract function application. If Arguments is [A1, ..., An], the
result represents "apply *Operator*(*A1*, ..., *An*)".
Creates an abstract atom literal. The print name of the atom is the character
sequence represented by Name.
Creates an abstract binary-template. A binary object is in this context a
sequence of an arbitrary number of bits. (The number of bits used to be evenly
divisible by 8, but after the introduction of bit strings in the Erlang
language, the choice was made to use the binary template for all bit strings.)
It is specified by zero or more bit-string template segments of arbitrary
lengths (in number of bits). If Segments is [S1, ..., Sn], the result
represents "#{*S1*, ..., *Sn*}#". All the Si must have type bitstr.
Creates an abstract bit-string template. These can only occur as components of
an abstract binary-template (see c_binary/1). The result represents
"#<*Value*>(*Size*, *Unit*, *Type*, *Flags*)", where Unit must represent a
positive integer constant, Type must represent a constant atom (one of
'integer', 'float', or 'binary'), and Flags must represent a constant
list "[*F1*, ..., *Fn*]" where all the Fi are atoms.
Creates an abstract inter-module call. If Arguments is [A1, ..., An], the
result represents "call *Module*:*Name*(*A1*, ..., *An*)".
Creates an abstract case-expression. If Clauses is [C1, ..., Cn], the result
represents "case *Argument* of *C1* ... *Cn* end". Clauses must not be
empty.
Creates an abstract catch-expression. The result represents "catch *Body*".
Creates an abstract character literal. If the local implementation of Erlang
defines char/0 as a subset of integer/0, this function is equivalent to
c_int/1. Otherwise, if the given value is an integer, it will be
converted to the character with the corresponding code. The lexical
representation of a character is "$*Char*", where Char is a single printing
character or an escape sequence.
Equivalent to c_clause(Patterns, c_atom(true), Body).
Creates an an abstract clause. If Patterns is [P1, ..., Pn], the result
represents "<*P1*, ..., *Pn*> when *Guard* -> *Body*".
Creates an abstract list constructor. The result represents
"[*Head* | *Tail*]". Note that if both Head and Tail have type literal,
then the result will also have type literal, and annotations on Head and
Tail are lost.
Creates an abstract list constructor skeleton. Does not fold constant literals,
i.e., the result always has type cons, representing "[*Head* | *Tail*]".
Creates an abstract floating-point literal. The lexical representation is the
decimal floating-point numeral of Value.
Equivalent to c_var({Name, Arity}).
Creates an abstract fun-expression. If Variables is [V1, ..., Vn], the
result represents "fun (*V1*, ..., *Vn*) -> *Body*". All the Vi must have
type var.
Creates an abstract integer literal. The lexical representation is the canonical
decimal numeral of Value.
Creates an abstract let-expression. If Variables is [V1, ..., Vn], the
result represents "let <*V1*, ..., *Vn*> = *Argument* in *Body*". All the Vi
must have type var.
Creates an abstract letrec-expression. If Definitions is
[{V1, F1}, ..., {Vn, Fn}], the result represents
"letrec *V1* = *F1* ... *Vn* = *Fn* in *Body*. All the Vi must have type
var and represent function names. All the Fi must have type 'fun'.
Creates an abstract module definition. The result represents
Creates an abstract empty list. The result represents "[]". The empty list is
traditionally called "nil".
Creates an abstract primitive operation call. If Arguments is [A1, ..., An],
the result represents "primop *Name*(*A1*, ..., *An*)". Name must be an atom
literal.
Creates an abstract receive-expression. If Clauses is [C1, ..., Cn], the
result represents "receive *C1* ... *Cn* after *Timeout* -> *Action* end".
Creates an abstract sequencing expression. The result represents
"do *Argument**Body*".
Creates an abstract string literal. Equivalent to creating an abstract list of
the corresponding character literals (cf. is_c_string/1),
but is typically more efficient. The lexical representation of a string is
""*Chars*"", where Chars is a sequence of printing characters or spaces.
Creates an abstract try-expression. If Variables is [V1, ..., Vn] and
ExceptionVars is [X1, ..., Xm], the result represents
"try *Argument* of <*V1*, ..., *Vn*> -> *Body* catch <*X1*, ..., *Xm*> -> *Handler*".
All the Vi and Xi must have type var.
Creates an abstract tuple. If Elements is [E1, ..., En], the result
represents "{*E1*, ..., *En*}". Note that if all nodes in Elements have type
literal, or if Elements is empty, then the result will also have type
literal and annotations on nodes in Elements are lost.
Creates an abstract tuple skeleton. Does not fold constant literals, i.e., the
result always has type tuple, representing "{*E1*, ..., *En*}", if
Elements is [E1, ..., En].
Creates an abstract value list. If Elements is [E1, ..., En], the result
represents "<*E1*, ..., *En*>".
Creates an abstract variable. A variable is identified by its name, given by the
Name parameter.
Returns the list of argument subtrees of an abstract inter-module call.
Returns the number of argument subtrees of an abstract inter-module call.
Returns the module subtree of an abstract inter-module call.
Returns the name subtree of an abstract inter-module call.
Returns the argument subtree of an abstract case-expression.
Equivalent to clause_arity(hd(case_clauses(Node))), but
potentially more efficient.
Returns the list of clause subtrees of an abstract case-expression.
Returns the body subtree of an abstract catch-expression.
Returns the literal string represented by an abstract character. This includes a
leading $ character. Currently, all characters that are not in the set of ISO
8859-1 (Latin-1) "printing" characters will be escaped.
Returns the value represented by an abstract character literal.
Returns the number of pattern subtrees of an abstract clause.
Returns the body subtree of an abstract clause.
Returns the guard subtree of an abstract clause.
Returns the list of pattern subtrees of an abstract clause.
Returns the list of all abstract variables in the patterns of an abstract clause. The order of listing is not defined.
Returns the Erlang term represented by a syntax tree. An exception is thrown if
Node does not represent a literal term.
Returns the head subtree of an abstract list constructor.
Returns the tail subtree of an abstract list constructor.
Copies the list of user annotations from Source to Target.
Returns the number of subtrees of a data constructor node. This is equivalent to
length(data_es(Node)), but potentially more efficient.
Returns the list of subtrees of a data constructor node. If the arity of the constructor is zero, the result is the empty list.
Returns a type descriptor for a data constructor node. (Cf.
is_data/1.) This is mainly useful for comparing types and for
constructing new nodes of the same type (cf. make_data/2). If
Node represents an integer, floating-point number, atom or empty list, the
result is {atomic, Value}, where Value is the value of
concrete(Node), otherwise the result is either cons or
tuple.
Returns the numeral string represented by a floating-point literal node.
Returns the value represented by a floating-point literal node.
Returns the arity part of an abstract function name variable.
Returns the identifier part of an abstract function name variable.
Assures that literals have a compact representation. This is occasionally useful
if c_cons_skel/2, c_tuple_skel/1 or
unfold_literal/1 were used in the construction of
Node, and you want to revert to the normal "folded" representation of
literals. If Node represents a tuple or list constructor, its elements are
rewritten recursively, and the node is reconstructed using
c_cons/2 or c_tuple/1, respectively; otherwise,
Node is not changed.
Translates an explicit record representation to a corresponding abstract syntax
tree. The records are defined in the file "core_parse.hrl".
Returns the number of parameter subtrees of an abstract fun-expression.
Returns the body subtree of an abstract fun-expression.
Returns the list of parameter subtrees of an abstract fun-expression.
Returns the list of user annotations associated with a syntax tree node. For a newly created node, this is the empty list. The annotations may be any terms.
Returns the numeral string represented by an integer literal node.
Returns the value represented by an integer literal node.
Returns true if Node is an abstract pattern alias, otherwise false.
Returns true if Node is an abstract function application, otherwise false.
Returns true if Node represents an atom literal, otherwise false.
Returns true if Node is an abstract binary-template; otherwise false.
Returns true if Node is an abstract bit-string template; otherwise false.
Returns true if Node is an abstract inter-module call expression; otherwise
false.
Returns true if Node is an abstract case-expression; otherwise false.
Returns true if Node is an abstract catch-expression, otherwise false.
Returns true if Node may represent a character literal, otherwise false.
Returns true if Node is an abstract clause, otherwise false.
Returns true if Node is an abstract list constructor, otherwise false.
Returns true if Node represents a floating-point literal, otherwise false.
Returns true if Node is an abstract function name variable, otherwise
false.
Returns true if Node is an abstract fun-expression, otherwise false.
Returns true if Node represents an integer literal, otherwise false.
Returns true if Node is an abstract let-expression, otherwise false.
Returns true if Node is an abstract letrec-expression, otherwise false.
Returns true if Node represents a proper list, otherwise false. A proper
list is either the empty list [], or a cons cell [*Head* | *Tail*], where
recursively Tail is a proper list.
Returns true if Node is an abstract map constructor, otherwise false.
Returns true if Node is an abstract module definition, otherwise false.
Returns true if Node is an abstract empty list, otherwise false.
Returns true if Node is an abstract primitive operation call, otherwise
false.
Returns true if Node is an abstract receive-expression, otherwise false.
Returns true if Node is an abstract sequencing expression, otherwise
false.
Returns true if Node may represent a string literal, otherwise false.
Strings are defined as lists of characters; see is_c_char/1
for details.
Returns true if Node is an abstract try-expression, otherwise false.
Returns true if Node is an abstract tuple, otherwise false.
Returns true if Node is an abstract value list; otherwise false.
Returns true if Node is an abstract variable, otherwise false.
Returns true if Node represents a data constructor, otherwise false. Data
constructors are cons cells, tuples, and atomic literals.
Returns true if Node is a leaf node, otherwise false. The current leaf
node types are literal and var.
Returns true if Node represents a literal term, otherwise false. This
function returns true if and only if the value of
concrete(Node) is defined.
Returns true if Term can be represented as a literal, otherwise false.
This function takes time proportional to the size of Term.
Returns true if Node may represent a "printing" character, otherwise
false. (Cf. is_c_char/1.) A "printing" character has either
a given graphical representation, or a "named" escape sequence such as "\n".
Currently, only ISO 8859-1 (Latin-1) character values are recognized.
Returns true if Node may represent a string literal containing only
"printing" characters, otherwise false. See is_c_string/1
and is_print_char/1 for details. Currently, only ISO
8859-1 (Latin-1) character values are recognized.
Returns the argument subtree of an abstract let-expression.
Returns the number of left-hand side variables of an abstract let-expression.
Returns the body subtree of an abstract let-expression.
Returns the list of left-hand side variables of an abstract let-expression.
Returns the body subtree of an abstract letrec-expression.
Returns the list of definitions of an abstract letrec-expression. If Node
represents "letrec *V1* = *F1* ... *Vn* = *Fn* in *Body*", the returned value
is [{V1, F1}, ..., {Vn, Fn}].
Returns the list of left-hand side function variable subtrees of a
letrec-expression. If Node represents
"letrec *V1* = *F1* ... *Vn* = *Fn* in *Body*", the returned value is
[V1, ..., Vn].
Returns the list of element subtrees of an abstract list. Node must represent
a proper list. E.g., if Node represents "[*X1*, *X2* | [*X3*, *X4* | []]",
then list_elements(Node) yields the list
[X1, X2, X3, X4].
Returns the number of element subtrees of an abstract list. Node must
represent a proper list. E.g., if Node represents
"[X1 | [X2, X3 | [X4, X5, X6]]]", then list_length(Node)
returns the integer 6.
Creates a data constructor node with the specified type and subtrees. (Cf.
data_type/1.) An exception is thrown if the length of
Elements is invalid for the given Type; see data_es/1 for
arity constraints on constructor types.
Like make_data/2, but analogous to
c_tuple_skel/1 and c_cons_skel/2.
Equivalent to make_list(List, none).
Creates an abstract list from the elements in List and the optional Tail. If
Tail is none, the result will represent a nil-terminated list, otherwise it
represents "[... | *Tail*]".
Creates a syntax tree with the given type and subtrees. Type must be a node
type name (cf. type/1) that does not denote a leaf node type (cf.
is_leaf/1). Groups must be a nonempty list of groups of
syntax trees, representing the subtrees of a node of the given type, in
left-to-right order as they would occur in the printed program text, grouped by
category as done by subtrees/1.
Creates a meta-representation of a syntax tree. The result represents an Erlang
expression "*MetaTree*" which, if evaluated, will yield a new syntax tree
representing the same source code text as Tree (although the actual data
representation may be different). The expression represented by MetaTree is
implementation independent with regard to the data structures used by the
abstract syntax tree implementation.
Returns the list of pairs of attribute key/value subtrees of an abstract module definition.
Returns the list of function definitions of an abstract module definition.
Returns the list of exports subtrees of an abstract module definition.
Returns the name subtree of an abstract module definition.
Returns the list of left-hand side function variable subtrees of an abstract module definition.
Returns the list of all abstract variables in the given patterns. An exception
is thrown if some element in Patterns does not represent a well-formed Core
Erlang clause pattern. The order of listing is not defined.
Returns the list of all abstract variables in a pattern. An exception is thrown
if Node does not represent a well-formed Core Erlang clause pattern. The order
of listing is not defined.
Returns the list of argument subtrees of an abstract primitive operation call.
Returns the number of argument subtrees of an abstract primitive operation call.
Returns the name subtree of an abstract primitive operation call.
Returns the action subtree of an abstract receive-expression.
Returns the list of clause subtrees of an abstract receive-expression.
Returns the timeout subtree of an abstract receive-expression.
Returns the argument subtree of an abstract sequencing expression.
Returns the body subtree of an abstract sequencing expression.
Sets the list of user annotations of Node to Annotations.
Returns the literal string represented by an abstract string. This includes
surrounding double-quote characters "...". Currently, characters that are not
in the set of ISO 8859-1 (Latin-1) "printing" characters will be escaped, except
for spaces.
Returns the value represented by an abstract string literal.
Returns the grouped list of all subtrees of a node. If Node is a leaf node
(cf. is_leaf/1), this is the empty list, otherwise the result
is always a nonempty list, containing the lists of subtrees of Node, in
left-to-right order as they occur in the printed program text, and grouped by
category. Often, each group contains only a single subtree.
Translates an abstract syntax tree to a corresponding explicit record
representation. The records are defined in the file "cerl.hrl".
Returns the expression subtree of an abstract try-expression.
Returns the success body subtree of an abstract try-expression.
Returns the list of exception variable subtrees of an abstract try-expression.
Returns the exception body subtree of an abstract try-expression.
Returns the list of success variable subtrees of an abstract try-expression.
Returns the number of element subtrees of an abstract tuple.
Returns the list of element subtrees of an abstract tuple.
Returns the type tag of Node. Current node types are
Assures that literals have a fully expanded representation. If Node represents
a literal tuple or list constructor, its elements are rewritten recursively, and
the node is reconstructed using c_cons_skel/2 or
c_tuple_skel/1, respectively; otherwise, Node is not
changed. The fold_literal/1 can be used to revert to the normal compact
representation.
See also: c_alias/2.
See also: c_binary/1.
Equivalent to update_c_bitstr(Node, Value, Size, abstract(1), Type, Flags).
See also: c_case/2.
See also: c_catch/1.
See also: c_cons/2.
Like update_c_fname/3, but takes the arity from Node.
See also: c_fun/2.
See also: c_letrec/2.
See also: c_primop/2.
See also: c_seq/2.
See also: c_tuple/1.
See also: c_tuple_skel/1.
See also: c_values/1.
See also: c_var/1.
See also: make_data/2.
Equivalent to update_list(Old, List, none).
See also: make_list/2, update_list/2.
Creates a syntax tree with the given subtrees, and the same type and annotations
as the Old node. This is equivalent to
ann_make_tree(get_ann(Node), type(Node), Groups), but
potentially more efficient.
Creates a syntax tree with the given type and subtrees, and the same annotations
as the Old node. This is equivalent to
ann_make_tree(get_ann(Node), Type, Groups), but
potentially more efficient.
Returns the number of element subtrees of an abstract value list.
Returns the list of element subtrees of an abstract value list.
Returns the name of an abstract variable.
Types
-type c_binary() :: #c_binary{anno :: list(), segments :: [cerl:c_bitstr()]}.
-type c_map() :: #c_map{anno :: list(), arg :: cerl:c_var() | cerl:c_literal(), es :: [cerl:c_map_pair()], is_pat :: boolean()}.
-type c_var() :: #c_var{anno :: list(), name :: cerl:var_name()}.
-type cerl() :: c_alias() | c_apply() | c_binary() | c_bitstr() | c_call() | c_case() | c_catch() | c_clause() | c_cons() | c_fun() | c_let() | c_letrec() | c_literal() | c_map() | c_map_pair() | c_module() | c_opaque() | c_primop() | c_receive() | c_seq() | c_try() | c_tuple() | c_values() | c_var().
-type ctype() ::
alias | apply | binary | bitstr | call | 'case' | 'catch' | clause | cons | 'fun' | 'let' |
letrec | literal | map | map_pair | module | primop | 'receive' | seq | 'try' | tuple |
values | var.
-type dtype() :: cons | tuple | {atomic, value()}.
Functions
Creates a syntax tree corresponding to an Erlang term. Term must be a literal
term, i.e., one that can be represented as a source code literal. Thus, it may
not contain a process identifier, port, reference, binary or function value as a
subterm.
Note: This is a constant time operation.
See also: ann_abstract/2, concrete/1, is_literal/1, is_literal_term/1.
Appends Annotations to the list of user annotations of Node.
Note: this is equivalent to
set_ann(Node, Annotations ++ get_ann(Node)), but potentially
more efficient.
Returns the pattern subtree of an abstract pattern alias.
See also: c_alias/2.
Returns the variable subtree of an abstract pattern alias.
See also: c_alias/2.
See also: abstract/1.
See also: c_alias/2.
See also: c_apply/2.
See also: c_atom/1.
See also: c_binary/1.
Equivalent to ann_c_bitstr(As, Value, Size, abstract(1), Type, Flags).
See also: ann_c_bitstr/5, c_bitstr/5.
See also: c_call/3.
See also: c_case/2.
See also: c_catch/1.
See also: c_char/1.
Equivalent to ann_c_clause(As, Patterns, c_atom(true), Body).
See also: c_clause/3.
See also: ann_c_clause/3, c_clause/3.
See also: c_cons/2.
See also: c_cons_skel/2.
See also: c_float/1.
Equivalent to ann_c_var(As, {Atom, Arity}).
See also: c_fname/2.
See also: c_fun/2.
See also: c_int/1.
See also: c_let/3.
See also: c_letrec/2.
-spec ann_c_map([term()], [c_map_pair()]) -> c_map() | c_literal().
-spec ann_c_map_pair([term()], cerl(), cerl(), cerl()) -> c_map_pair().
-spec ann_c_map_pattern([term()], [c_map_pair()]) -> c_map().
See also: ann_c_module/5, c_module/3.
-spec ann_c_module([term()], cerl(), [cerl()], [{cerl(), cerl()}], [{cerl(), cerl()}]) -> c_module().
See also: ann_c_module/4, c_module/4.
See also: c_nil/0.
See also: c_primop/2.
Equivalent to ann_c_receive(As, Clauses, c_atom(infinity), c_atom(true)).
See also: c_atom/1, c_receive/3.
See also: ann_c_receive/2, c_receive/3.
See also: c_seq/2.
See also: c_string/1.
See also: c_try/5.
See also: c_tuple/1.
See also: c_tuple_skel/1.
See also: c_values/1.
See also: c_var/1.
See also: make_data/2.
See also: make_data_skel/2.
Equivalent to ann_make_list(As, List, none).
See also: ann_make_list/2, make_list/2.
Creates a syntax tree with the given annotations, type and subtrees. See
make_tree/2 for details.
See also: make_tree/2.
Returns the list of argument subtrees of an abstract function application.
See also: apply_arity/1, c_apply/2.
Returns the number of argument subtrees of an abstract function application.
Note: this is equivalent to length(apply_args(Node)), but
potentially more efficient.
See also: apply_args/1, c_apply/2.
Returns the operator subtree of an abstract function application.
See also: c_apply/2.
-spec atom_lit(cerl()) -> nonempty_string().
Returns the literal string represented by an abstract atom. This always includes surrounding single-quote characters.
Note that an abstract atom may have several literal representations, and that
the representation yielded by this function is not fixed; e.g.,
atom_lit(c_atom("a\012b")) could yield the string
"\'a\\nb\'".
See also: c_atom/1.
Returns the printname of an abstract atom.
See also: c_atom/1.
Returns the value represented by an abstract atom.
See also: c_atom/1.
Returns the list of segment subtrees of an abstract binary-template.
See also: c_binary/1, c_bitstr/5.
-spec bitstr_bitsize(c_bitstr()) -> all | any | utf | non_neg_integer().
Returns the total size in bits of an abstract bit-string template. If the size
field is an integer literal, the result is the product of the size and unit
values; if the size field is the atom literal all, the atom all is returned.
If the size is not a literal, the atom any is returned.
See also: c_bitstr/5.
Returns the flags subtree of an abstract bit-string template.
See also: c_bitstr/5.
Returns the size subtree of an abstract bit-string template.
See also: c_bitstr/5.
Returns the type subtree of an abstract bit-string template.
See also: c_bitstr/5.
Returns the unit subtree of an abstract bit-string template.
See also: c_bitstr/5.
Returns the value subtree of an abstract bit-string template.
See also: c_bitstr/5.
Creates an abstract pattern alias. The result represents
"*Variable* = *Pattern*".
See also: alias_pat/1, alias_var/1, ann_c_alias/3, c_clause/3,
is_c_alias/1, update_c_alias/3.
Creates an abstract function application. If Arguments is [A1, ..., An], the
result represents "apply *Operator*(*A1*, ..., *An*)".
See also: ann_c_apply/3, apply_args/1, apply_arity/1, apply_op/1,
c_call/3, c_primop/2, is_c_apply/1, update_c_apply/3.
Creates an abstract atom literal. The print name of the atom is the character
sequence represented by Name.
Note: passing a string as argument to this function causes a corresponding atom to be created for the internal representation.
See also: ann_c_atom/2, atom_lit/1, atom_name/1, atom_val/1,
is_c_atom/1.
Creates an abstract binary-template. A binary object is in this context a
sequence of an arbitrary number of bits. (The number of bits used to be evenly
divisible by 8, but after the introduction of bit strings in the Erlang
language, the choice was made to use the binary template for all bit strings.)
It is specified by zero or more bit-string template segments of arbitrary
lengths (in number of bits). If Segments is [S1, ..., Sn], the result
represents "#{*S1*, ..., *Sn*}#". All the Si must have type bitstr.
See also: ann_c_binary/2, binary_segments/1, c_bitstr/5,
is_c_binary/1, update_c_binary/2.
Equivalent to c_bitstr(Value, abstract(all), abstract(1), Type, Flags).
Equivalent to c_bitstr(Value, Size, abstract(1), Type, Flags).
Creates an abstract bit-string template. These can only occur as components of
an abstract binary-template (see c_binary/1). The result represents
"#<*Value*>(*Size*, *Unit*, *Type*, *Flags*)", where Unit must represent a
positive integer constant, Type must represent a constant atom (one of
'integer', 'float', or 'binary'), and Flags must represent a constant
list "[*F1*, ..., *Fn*]" where all the Fi are atoms.
See also: ann_c_bitstr/6, bitstr_flags/1, bitstr_size/1,
bitstr_type/1, bitstr_unit/1, bitstr_val/1, c_binary/1, is_c_bitstr/1,
update_c_bitstr/6.
Creates an abstract inter-module call. If Arguments is [A1, ..., An], the
result represents "call *Module*:*Name*(*A1*, ..., *An*)".
See also: ann_c_call/4, c_apply/2, c_primop/2, call_args/1,
call_arity/1, call_module/1, call_name/1, is_c_call/1,
update_c_call/4.
Creates an abstract case-expression. If Clauses is [C1, ..., Cn], the result
represents "case *Argument* of *C1* ... *Cn* end". Clauses must not be
empty.
See also: ann_c_case/3, c_clause/3, case_arg/1, case_arity/1,
case_clauses/1, is_c_case/1, update_c_case/3.
Creates an abstract catch-expression. The result represents "catch *Body*".
Note: catch-expressions can be rewritten as try-expressions, and will eventually be removed from Core Erlang.
See also: ann_c_catch/2, c_try/5, catch_body/1, is_c_catch/1,
update_c_catch/2.
-spec c_char(non_neg_integer()) -> c_literal().
Creates an abstract character literal. If the local implementation of Erlang
defines char/0 as a subset of integer/0, this function is equivalent to
c_int/1. Otherwise, if the given value is an integer, it will be
converted to the character with the corresponding code. The lexical
representation of a character is "$*Char*", where Char is a single printing
character or an escape sequence.
See also: ann_c_char/2, c_int/1, c_string/1, char_lit/1, char_val/1,
is_c_char/1, is_print_char/1.
Equivalent to c_clause(Patterns, c_atom(true), Body).
See also: c_atom/1.
Creates an an abstract clause. If Patterns is [P1, ..., Pn], the result
represents "<*P1*, ..., *Pn*> when *Guard* -> *Body*".
See also: ann_c_clause/4, c_case/2, c_clause/2, c_receive/3,
clause_arity/1, clause_body/1, clause_guard/1, clause_pats/1,
clause_vars/1, is_c_clause/1, update_c_clause/4.
Creates an abstract list constructor. The result represents
"[*Head* | *Tail*]". Note that if both Head and Tail have type literal,
then the result will also have type literal, and annotations on Head and
Tail are lost.
Recall that in Erlang, the tail element of a list constructor is not necessarily a list.
See also: ann_c_cons/3, c_cons_skel/2, c_nil/0, cons_hd/1,
cons_tl/1, is_c_cons/1, is_c_list/1, list_elements/1, list_length/1,
make_list/2, update_c_cons/3.
Creates an abstract list constructor skeleton. Does not fold constant literals,
i.e., the result always has type cons, representing "[*Head* | *Tail*]".
This function is occasionally useful when it is necessary to have annotations on
the subnodes of a list constructor node, even when the subnodes are constant
literals. Note however that is_literal/1 will yield false
and concrete/1 will fail if passed the result from this
function.
fold_literal/1 can be used to revert a node to the
normal-form representation.
See also: ann_c_cons_skel/3, c_cons/2, c_nil/0, concrete/1,
fold_literal/1, is_c_cons/1, is_c_list/1, is_literal/1,
update_c_cons_skel/3.
Creates an abstract floating-point literal. The lexical representation is the
decimal floating-point numeral of Value.
See also: ann_c_float/2, float_lit/1, float_val/1, is_c_float/1.
Equivalent to c_var({Name, Arity}).
See also: ann_c_fname/3, fname_arity/1, fname_id/1, is_c_fname/1,
update_c_fname/3.
Creates an abstract fun-expression. If Variables is [V1, ..., Vn], the
result represents "fun (*V1*, ..., *Vn*) -> *Body*". All the Vi must have
type var.
See also: ann_c_fun/3, fun_arity/1, fun_body/1, fun_vars/1,
is_c_fun/1, update_c_fun/3.
Creates an abstract integer literal. The lexical representation is the canonical
decimal numeral of Value.
See also: ann_c_int/2, c_char/1, int_lit/1, int_val/1, is_c_int/1.
Creates an abstract let-expression. If Variables is [V1, ..., Vn], the
result represents "let <*V1*, ..., *Vn*> = *Argument* in *Body*". All the Vi
must have type var.
See also: ann_c_let/4, is_c_let/1, let_arg/1, let_arity/1,
let_body/1, let_vars/1, update_c_let/4.
Creates an abstract letrec-expression. If Definitions is
[{V1, F1}, ..., {Vn, Fn}], the result represents
"letrec *V1* = *F1* ... *Vn* = *Fn* in *Body*. All the Vi must have type
var and represent function names. All the Fi must have type 'fun'.
See also: ann_c_letrec/3, is_c_letrec/1, letrec_body/1, letrec_defs/1,
letrec_vars/1, update_c_letrec/3.
-spec c_map([c_map_pair()]) -> c_map().
-spec c_map_pair(cerl(), cerl()) -> c_map_pair().
-spec c_map_pair_exact(cerl(), cerl()) -> c_map_pair().
-spec c_map_pattern([c_map_pair()]) -> c_map().
Equivalent to c_module(Name, Exports, [], Definitions).
Creates an abstract module definition. The result represents
module Name [E1, ..., Ek]
attributes [K1 = T1, ...,
Km = Tm]
V1 = F1
...
Vn = Fn
endif Exports = [E1, ..., Ek], Attributes = [{K1, T1}, ..., {Km, Tm}], and
Definitions = [{V1, F1}, ..., {Vn, Fn}].
Name and all the Ki must be atom literals, and all the Ti must be constant
literals. All the Vi and Ei must have type var and represent function
names. All the Fi must have type 'fun'.
See also: ann_c_module/4, ann_c_module/5, c_atom/1, c_fun/2,
c_module/3, c_var/1, is_literal/1, module_attrs/1, module_defs/1,
module_exports/1, module_name/1, module_vars/1, update_c_module/5.
-spec c_nil() -> c_literal().
Creates an abstract empty list. The result represents "[]". The empty list is
traditionally called "nil".
See also: ann_c_nil/1, c_cons/2, is_c_list/1.
Creates an abstract primitive operation call. If Arguments is [A1, ..., An],
the result represents "primop *Name*(*A1*, ..., *An*)". Name must be an atom
literal.
See also: ann_c_primop/3, c_apply/2, c_call/3, is_c_primop/1,
primop_args/1, primop_arity/1, primop_name/1, update_c_primop/3.
Equivalent to c_receive(Clauses, c_atom(infinity), c_atom(true)).
See also: c_atom/1.
Creates an abstract receive-expression. If Clauses is [C1, ..., Cn], the
result represents "receive *C1* ... *Cn* after *Timeout* -> *Action* end".
See also: ann_c_receive/4, c_receive/1, is_c_receive/1,
receive_action/1, receive_clauses/1, receive_timeout/1,
update_c_receive/4.
Creates an abstract sequencing expression. The result represents
"do *Argument**Body*".
See also: ann_c_seq/3, is_c_seq/1, seq_arg/1, seq_body/1,
update_c_seq/3.
Creates an abstract string literal. Equivalent to creating an abstract list of
the corresponding character literals (cf. is_c_string/1),
but is typically more efficient. The lexical representation of a string is
""*Chars*"", where Chars is a sequence of printing characters or spaces.
See also: ann_c_string/2, c_char/1, is_c_string/1, is_print_string/1,
string_lit/1, string_val/1.
Creates an abstract try-expression. If Variables is [V1, ..., Vn] and
ExceptionVars is [X1, ..., Xm], the result represents
"try *Argument* of <*V1*, ..., *Vn*> -> *Body* catch <*X1*, ..., *Xm*> -> *Handler*".
All the Vi and Xi must have type var.
See also: ann_c_try/6, c_catch/1, is_c_try/1, try_arg/1, try_body/1,
try_vars/1, update_c_try/6.
Creates an abstract tuple. If Elements is [E1, ..., En], the result
represents "{*E1*, ..., *En*}". Note that if all nodes in Elements have type
literal, or if Elements is empty, then the result will also have type
literal and annotations on nodes in Elements are lost.
Recall that Erlang has distinct 1-tuples, i.e., {X} is always distinct from
X itself.
See also: ann_c_tuple/2, c_tuple_skel/1, is_c_tuple/1, tuple_arity/1,
tuple_es/1, update_c_tuple/2.
Creates an abstract tuple skeleton. Does not fold constant literals, i.e., the
result always has type tuple, representing "{*E1*, ..., *En*}", if
Elements is [E1, ..., En].
This function is occasionally useful when it is necessary to have annotations on
the subnodes of a tuple node, even when all the subnodes are constant literals.
Note however that is_literal/1 will yield false and
concrete/1 will fail if passed the result from this function.
fold_literal/1 can be used to revert a node to the
normal-form representation.
See also: ann_c_tuple_skel/2, c_tuple/1, concrete/1, fold_literal/1,
is_c_tuple/1, is_literal/1, tuple_es/1, update_c_tuple_skel/2.
Creates an abstract value list. If Elements is [E1, ..., En], the result
represents "<*E1*, ..., *En*>".
See also: ann_c_values/2, is_c_values/1, update_c_values/2,
values_arity/1, values_es/1.
Creates an abstract variable. A variable is identified by its name, given by the
Name parameter.
If a name is given by a single atom, it should either be a "simple" atom which
does not need to be single-quoted in Erlang, or otherwise its print name should
correspond to a proper Erlang variable, i.e., begin with an uppercase character
or an underscore. Names on the form {A, N} represent function name variables
"*A*/*N*"; these are special variables which may be bound only in the function
definitions of a module or a letrec. They may not be bound in let
expressions and cannot occur in clause patterns. The atom A in a function name
may be any atom; the integer N must be nonnegative. The functions
c_fname/2 etc. are utilities for handling function name
variables.
When printing variable names, they must have the form of proper Core Erlang
variables and function names. E.g., a name represented by an integer such as
42 could be formatted as "_42", an atom 'Xxx' simply as "Xxx", and an
atom foo as "_foo". However, one must assure that any two valid distinct
names are never mapped to the same strings. Tuples such as {foo, 2}
representing function names can simply by formatted as "'foo'/2", with no risk
of conflicts.
See also: ann_c_var/2, c_fname/2, c_letrec/2, c_module/4,
is_c_var/1, update_c_var/2, var_name/1.
Returns the list of argument subtrees of an abstract inter-module call.
See also: c_call/3, call_arity/1.
Returns the number of argument subtrees of an abstract inter-module call.
Note: this is equivalent to length(call_args(Node)), but
potentially more efficient.
See also: c_call/3, call_args/1.
Returns the module subtree of an abstract inter-module call.
See also: c_call/3.
Returns the name subtree of an abstract inter-module call.
See also: c_call/3.
Returns the argument subtree of an abstract case-expression.
See also: c_case/2.
-spec case_arity(c_case()) -> non_neg_integer().
Equivalent to clause_arity(hd(case_clauses(Node))), but
potentially more efficient.
See also: c_case/2, case_clauses/1, clause_arity/1.
Returns the list of clause subtrees of an abstract case-expression.
See also: c_case/2, case_arity/1.
Returns the body subtree of an abstract catch-expression.
See also: c_catch/1.
-spec char_lit(c_literal()) -> nonempty_string().
Returns the literal string represented by an abstract character. This includes a
leading $ character. Currently, all characters that are not in the set of ISO
8859-1 (Latin-1) "printing" characters will be escaped.
See also: c_char/1.
Returns the value represented by an abstract character literal.
See also: c_char/1.
-spec clause_arity(c_clause()) -> non_neg_integer().
Returns the number of pattern subtrees of an abstract clause.
Note: this is equivalent to length(clause_pats(Node)), but
potentially more efficient.
See also: c_clause/3, clause_pats/1.
Returns the body subtree of an abstract clause.
See also: c_clause/3.
Returns the guard subtree of an abstract clause.
See also: c_clause/3.
Returns the list of pattern subtrees of an abstract clause.
See also: c_clause/3, clause_arity/1.
Returns the list of all abstract variables in the patterns of an abstract clause. The order of listing is not defined.
See also: c_clause/3, pat_list_vars/1.
Returns the Erlang term represented by a syntax tree. An exception is thrown if
Node does not represent a literal term.
Note: This is a constant time operation.
See also: abstract/1, is_literal/1.
Returns the head subtree of an abstract list constructor.
See also: c_cons/2.
Returns the tail subtree of an abstract list constructor.
Recall that the tail does not necessarily represent a proper list.
See also: c_cons/2.
Copies the list of user annotations from Source to Target.
Note: this is equivalent to set_ann(Target, get_ann(Source)),
but potentially more efficient.
-spec data_arity(c_lct()) -> non_neg_integer().
Returns the number of subtrees of a data constructor node. This is equivalent to
length(data_es(Node)), but potentially more efficient.
Returns the list of subtrees of a data constructor node. If the arity of the constructor is zero, the result is the empty list.
Note: if data_type(Node) is cons, the number of subtrees is
exactly two. If data_type(Node) is {atomic, Value}, the
number of subtrees is zero.
See also: data_arity/1, data_type/1, is_data/1, make_data/2.
Returns a type descriptor for a data constructor node. (Cf.
is_data/1.) This is mainly useful for comparing types and for
constructing new nodes of the same type (cf. make_data/2). If
Node represents an integer, floating-point number, atom or empty list, the
result is {atomic, Value}, where Value is the value of
concrete(Node), otherwise the result is either cons or
tuple.
Type descriptors can be compared for equality or order (in the Erlang term order), but remember that floating-point values should in general never be tested for equality.
See also: concrete/1, is_data/1, make_data/2, type/1.
Returns the numeral string represented by a floating-point literal node.
See also: c_float/1.
Returns the value represented by a floating-point literal node.
See also: c_float/1.
Returns the arity part of an abstract function name variable.
See also: c_fname/2, fname_id/1.
Returns the identifier part of an abstract function name variable.
See also: c_fname/2, fname_arity/1.
Assures that literals have a compact representation. This is occasionally useful
if c_cons_skel/2, c_tuple_skel/1 or
unfold_literal/1 were used in the construction of
Node, and you want to revert to the normal "folded" representation of
literals. If Node represents a tuple or list constructor, its elements are
rewritten recursively, and the node is reconstructed using
c_cons/2 or c_tuple/1, respectively; otherwise,
Node is not changed.
See also: c_cons/2, c_cons_skel/2, c_tuple/1, c_tuple_skel/1,
is_literal/1, unfold_literal/1.
Translates an explicit record representation to a corresponding abstract syntax
tree. The records are defined in the file "core_parse.hrl".
See also: to_records/1, type/1.
Returns the number of parameter subtrees of an abstract fun-expression.
Note: this is equivalent to length(fun_vars(Node)), but
potentially more efficient.
See also: c_fun/2, fun_vars/1.
Returns the body subtree of an abstract fun-expression.
See also: c_fun/2.
Returns the list of parameter subtrees of an abstract fun-expression.
See also: c_fun/2, fun_arity/1.
Returns the list of user annotations associated with a syntax tree node. For a newly created node, this is the empty list. The annotations may be any terms.
See also: set_ann/2.
Returns the numeral string represented by an integer literal node.
See also: c_int/1.
Returns the value represented by an integer literal node.
See also: c_int/1.
Returns true if Node is an abstract pattern alias, otherwise false.
See also: c_alias/2.
Returns true if Node is an abstract function application, otherwise false.
See also: c_apply/2.
Returns true if Node represents an atom literal, otherwise false.
See also: c_atom/1.
Returns true if Node is an abstract binary-template; otherwise false.
See also: c_binary/1.
Returns true if Node is an abstract bit-string template; otherwise false.
See also: c_bitstr/5.
Returns true if Node is an abstract inter-module call expression; otherwise
false.
See also: c_call/3.
Returns true if Node is an abstract case-expression; otherwise false.
See also: c_case/2.
Returns true if Node is an abstract catch-expression, otherwise false.
See also: c_catch/1.
Returns true if Node may represent a character literal, otherwise false.
If the local implementation of Erlang defines char/0 as a subset of
integer/0, then is_c_int(*Node*) will also yield true.
See also: c_char/1, is_print_char/1.
Returns true if Node is an abstract clause, otherwise false.
See also: c_clause/3.
Returns true if Node is an abstract list constructor, otherwise false.
Returns true if Node represents a floating-point literal, otherwise false.
See also: c_float/1.
Returns true if Node is an abstract function name variable, otherwise
false.
See also: c_fname/2, c_var/1, var_name/1.
Returns true if Node is an abstract fun-expression, otherwise false.
See also: c_fun/2.
Returns true if Node represents an integer literal, otherwise false.
See also: c_int/1.
Returns true if Node is an abstract let-expression, otherwise false.
See also: c_let/3.
Returns true if Node is an abstract letrec-expression, otherwise false.
See also: c_letrec/2.
Returns true if Node represents a proper list, otherwise false. A proper
list is either the empty list [], or a cons cell [*Head* | *Tail*], where
recursively Tail is a proper list.
Note: Because Node is a syntax tree, the actual run-time values corresponding
to its subtrees may often be partially or completely unknown. Thus, if Node
represents e.g. "[... | Ns]" (where Ns is a variable), then the function
will return false, because it is not known whether Ns will be bound to a
list at run-time. If Node instead represents e.g. "[1, 2, 3]" or
"[A | []]", then the function will return true.
See also: c_cons/2, c_nil/0, list_elements/1, list_length/1.
Returns true if Node is an abstract map constructor, otherwise false.
Returns true if Node is an abstract module definition, otherwise false.
See also: type/1.
Returns true if Node is an abstract empty list, otherwise false.
Returns true if Node is an abstract primitive operation call, otherwise
false.
See also: c_primop/2.
Returns true if Node is an abstract receive-expression, otherwise false.
See also: c_receive/3.
Returns true if Node is an abstract sequencing expression, otherwise
false.
See also: c_seq/2.
Returns true if Node may represent a string literal, otherwise false.
Strings are defined as lists of characters; see is_c_char/1
for details.
See also: c_string/1, is_c_char/1, is_print_string/1.
Returns true if Node is an abstract try-expression, otherwise false.
See also: c_try/5.
Returns true if Node is an abstract tuple, otherwise false.
See also: c_tuple/1.
Returns true if Node is an abstract value list; otherwise false.
See also: c_values/1.
Returns true if Node is an abstract variable, otherwise false.
See also: c_var/1.
Returns true if Node represents a data constructor, otherwise false. Data
constructors are cons cells, tuples, and atomic literals.
See also: data_arity/1, data_es/1, data_type/1.
Returns true if Node is a leaf node, otherwise false. The current leaf
node types are literal and var.
Note: all literals (cf. is_literal/1) are leaf nodes, even
if they represent structured (constant) values such as {foo, [bar, baz]}. Also
note that variables are leaf nodes but not literals.
See also: is_literal/1, type/1.
Returns true if Node represents a literal term, otherwise false. This
function returns true if and only if the value of
concrete(Node) is defined.
Note: This is a constant time operation.
See also: abstract/1, concrete/1, fold_literal/1.
Returns true if Term can be represented as a literal, otherwise false.
This function takes time proportional to the size of Term.
See also: abstract/1.
Returns true if Node may represent a "printing" character, otherwise
false. (Cf. is_c_char/1.) A "printing" character has either
a given graphical representation, or a "named" escape sequence such as "\n".
Currently, only ISO 8859-1 (Latin-1) character values are recognized.
See also: c_char/1, is_c_char/1.
Returns true if Node may represent a string literal containing only
"printing" characters, otherwise false. See is_c_string/1
and is_print_char/1 for details. Currently, only ISO
8859-1 (Latin-1) character values are recognized.
See also: c_string/1, is_c_string/1, is_print_char/1.
Returns the argument subtree of an abstract let-expression.
See also: c_let/3.
-spec let_arity(c_let()) -> non_neg_integer().
Returns the number of left-hand side variables of an abstract let-expression.
Note: this is equivalent to length(let_vars(Node)), but
potentially more efficient.
See also: c_let/3, let_vars/1.
Returns the body subtree of an abstract let-expression.
See also: c_let/3.
Returns the list of left-hand side variables of an abstract let-expression.
See also: c_let/3, let_arity/1.
Returns the body subtree of an abstract letrec-expression.
See also: c_letrec/2.
Returns the list of definitions of an abstract letrec-expression. If Node
represents "letrec *V1* = *F1* ... *Vn* = *Fn* in *Body*", the returned value
is [{V1, F1}, ..., {Vn, Fn}].
See also: c_letrec/2.
Returns the list of left-hand side function variable subtrees of a
letrec-expression. If Node represents
"letrec *V1* = *F1* ... *Vn* = *Fn* in *Body*", the returned value is
[V1, ..., Vn].
See also: c_letrec/2.
Returns the list of element subtrees of an abstract list. Node must represent
a proper list. E.g., if Node represents "[*X1*, *X2* | [*X3*, *X4* | []]",
then list_elements(Node) yields the list
[X1, X2, X3, X4].
See also: c_cons/2, c_nil/0, is_c_list/1, list_length/1,
make_list/2.
-spec list_length(c_cons() | c_literal()) -> non_neg_integer().
Returns the number of element subtrees of an abstract list. Node must
represent a proper list. E.g., if Node represents
"[X1 | [X2, X3 | [X4, X5, X6]]]", then list_length(Node)
returns the integer 6.
Note: this is equivalent to length(list_elements(Node)), but
potentially more efficient.
See also: c_cons/2, c_nil/0, is_c_list/1, list_elements/1.
Creates a data constructor node with the specified type and subtrees. (Cf.
data_type/1.) An exception is thrown if the length of
Elements is invalid for the given Type; see data_es/1 for
arity constraints on constructor types.
See also: ann_make_data/3, data_es/1, data_type/1, make_data_skel/2,
update_data/3.
Like make_data/2, but analogous to
c_tuple_skel/1 and c_cons_skel/2.
See also: ann_make_data_skel/3, c_cons_skel/2, c_tuple_skel/1,
make_data/2, update_data_skel/3.
Equivalent to make_list(List, none).
Creates an abstract list from the elements in List and the optional Tail. If
Tail is none, the result will represent a nil-terminated list, otherwise it
represents "[... | *Tail*]".
See also: ann_make_list/3, c_cons/2, c_nil/0, list_elements/1,
update_list/3.
Creates a syntax tree with the given type and subtrees. Type must be a node
type name (cf. type/1) that does not denote a leaf node type (cf.
is_leaf/1). Groups must be a nonempty list of groups of
syntax trees, representing the subtrees of a node of the given type, in
left-to-right order as they would occur in the printed program text, grouped by
category as done by subtrees/1.
The result of
ann_make_tree(get_ann(Node), type(Node), subtrees(Node))
(cf. update_tree/2) represents the same source code text as
the original Node, assuming that subtrees(Node) yields a
nonempty list. However, it does not necessarily have the exact same data
representation as Node.
See also: ann_make_tree/3, is_leaf/1, subtrees/1, type/1,
update_tree/2.
-spec map_es(c_map() | c_literal()) -> [c_map_pair()].
-spec map_pair_key(c_map_pair()) -> cerl().
-spec map_pair_op(c_map_pair()) -> map_op().
-spec map_pair_val(c_map_pair()) -> cerl().
Creates a meta-representation of a syntax tree. The result represents an Erlang
expression "*MetaTree*" which, if evaluated, will yield a new syntax tree
representing the same source code text as Tree (although the actual data
representation may be different). The expression represented by MetaTree is
implementation independent with regard to the data structures used by the
abstract syntax tree implementation.
Any node in Tree whose node type is var (cf. type/1), and
whose list of annotations (cf. get_ann/1) contains the atom
meta_var, will remain unchanged in the resulting tree, except that exactly one
occurrence of meta_var is removed from its annotation list.
The main use of the function meta/1 is to transform a data
structure Tree, which represents a piece of program code, into a form that is
representation independent when printed. E.g., suppose Tree represents a
variable named "V". Then (assuming a function print/1 for printing syntax
trees), evaluating print(abstract(Tree)) - simply using
abstract/1 to map the actual data structure onto a syntax tree
representation - would output a string that might look something like
"{var, ..., 'V'}", which is obviously dependent on the implementation of the
abstract syntax trees. This could e.g. be useful for caching a syntax tree in a
file. However, in some situations like in a program generator generator (with
two "generator"), it may be unacceptable. Using print(meta(Tree)) instead
would output a representation independent syntax tree generating expression;
in the above case, something like "cerl:c_var('V')".
The implementation tries to generate compact code with respect to literals and lists.
See also: abstract/1, get_ann/1, type/1.
Returns the list of pairs of attribute key/value subtrees of an abstract module definition.
See also: c_module/4.
Returns the list of function definitions of an abstract module definition.
See also: c_module/4.
Returns the list of exports subtrees of an abstract module definition.
See also: c_module/4.
Returns the name subtree of an abstract module definition.
See also: c_module/4.
Returns the list of left-hand side function variable subtrees of an abstract module definition.
See also: c_module/4.
Returns the list of all abstract variables in the given patterns. An exception
is thrown if some element in Patterns does not represent a well-formed Core
Erlang clause pattern. The order of listing is not defined.
See also: clause_vars/1, pat_vars/1.
Returns the list of all abstract variables in a pattern. An exception is thrown
if Node does not represent a well-formed Core Erlang clause pattern. The order
of listing is not defined.
See also: clause_vars/1, pat_list_vars/1.
Returns the list of argument subtrees of an abstract primitive operation call.
See also: c_primop/2, primop_arity/1.
Returns the number of argument subtrees of an abstract primitive operation call.
Note: this is equivalent to length(primop_args(Node)), but
potentially more efficient.
See also: c_primop/2, primop_args/1.
Returns the name subtree of an abstract primitive operation call.
See also: c_primop/2.
Returns the action subtree of an abstract receive-expression.
See also: c_receive/3.
Returns the list of clause subtrees of an abstract receive-expression.
See also: c_receive/3.
Returns the timeout subtree of an abstract receive-expression.
See also: c_receive/3.
Returns the argument subtree of an abstract sequencing expression.
See also: c_seq/2.
Returns the body subtree of an abstract sequencing expression.
See also: c_seq/2.
Sets the list of user annotations of Node to Annotations.
See also: add_ann/2, copy_ann/2, get_ann/1.
-spec string_lit(c_literal()) -> nonempty_string().
Returns the literal string represented by an abstract string. This includes
surrounding double-quote characters "...". Currently, characters that are not
in the set of ISO 8859-1 (Latin-1) "printing" characters will be escaped, except
for spaces.
See also: c_string/1.
Returns the value represented by an abstract string literal.
See also: c_string/1.
Returns the grouped list of all subtrees of a node. If Node is a leaf node
(cf. is_leaf/1), this is the empty list, otherwise the result
is always a nonempty list, containing the lists of subtrees of Node, in
left-to-right order as they occur in the printed program text, and grouped by
category. Often, each group contains only a single subtree.
Depending on the type of Node, the size of some groups may be variable (e.g.,
the group consisting of all the elements of a tuple), while others always
contain the same number of elements - usually exactly one (e.g., the group
containing the argument expression of a case-expression). Note, however, that
the exact structure of the returned list (for a given node type) should in
general not be depended upon, since it might be subject to change without
notice.
The function subtrees/1 and the constructor functions
make_tree/2 and update_tree/2 can be a
great help if one wants to traverse a syntax tree, visiting all its subtrees,
but treat nodes of the tree in a uniform way in most or all cases. Using these
functions makes this simple, and also assures that your code is not overly
sensitive to extensions of the syntax tree data type, because any node types not
explicitly handled by your code can be left to a default case.
For example:
postorder(F, Tree) ->
F(case subtrees(Tree) of
[] -> Tree;
List -> update_tree(Tree,
[[postorder(F, Subtree)
|| Subtree <- Group]
|| Group <- List])
end).
maps the function F on Tree and all its subtrees, doing a post-order
traversal of the syntax tree. (Note the use of
update_tree/2 to preserve annotations.) For a simple
function like:
f(Node) ->
case type(Node) of
atom -> atom("a_" ++ atom_name(Node));
_ -> Node
end.
the call postorder(fun f/1, Tree) will yield a new representation of Tree in
which all atom names have been extended with the prefix "a_", but nothing else
(including annotations) has been changed.
See also: is_leaf/1, make_tree/2, update_tree/2.
Translates an abstract syntax tree to a corresponding explicit record
representation. The records are defined in the file "cerl.hrl".
See also: from_records/1, type/1.
Returns the expression subtree of an abstract try-expression.
See also: c_try/5.
Returns the success body subtree of an abstract try-expression.
See also: c_try/5.
Returns the list of exception variable subtrees of an abstract try-expression.
See also: c_try/5.
Returns the exception body subtree of an abstract try-expression.
See also: c_try/5.
Returns the list of success variable subtrees of an abstract try-expression.
See also: c_try/5.
-spec tuple_arity(c_tuple() | c_literal()) -> non_neg_integer().
Returns the number of element subtrees of an abstract tuple.
Note: this is equivalent to length(tuple_es(Node)), but
potentially more efficient.
See also: c_tuple/1, tuple_es/1.
Returns the list of element subtrees of an abstract tuple.
See also: c_tuple/1.
Returns the type tag of Node. Current node types are:
| alias | apply | binary | bitstr | call | case | catch | clause |
| cons | fun | let | letrec | literal | map | map_pair | module |
| primop | receive | seq | try | tuple | values | var |
Note: The name of the primary constructor function for a node type is always the
name of the type itself, prefixed by "c_"; recognizer predicates are
correspondingly prefixed by "is_c_". Furthermore, to simplify preservation of
annotations (cf. get_ann/1), there are analogous constructor
functions prefixed by "ann_c_" and "update_c_", for setting the annotation
list of the new node to either a specific value or to the annotations of an
existing node, respectively.
See also: abstract/1, c_alias/2, c_apply/2, c_binary/1, c_bitstr/5,
c_call/3, c_case/2, c_catch/1, c_clause/3, c_cons/2, c_fun/2,
c_let/3, c_letrec/2, c_module/3, c_primop/2, c_receive/1, c_seq/2,
c_try/5, c_tuple/1, c_values/1, c_var/1, data_type/1,
from_records/1, get_ann/1, meta/1, subtrees/1, to_records/1.
Assures that literals have a fully expanded representation. If Node represents
a literal tuple or list constructor, its elements are rewritten recursively, and
the node is reconstructed using c_cons_skel/2 or
c_tuple_skel/1, respectively; otherwise, Node is not
changed. The fold_literal/1 can be used to revert to the normal compact
representation.
See also: c_cons/2, c_cons_skel/2, c_tuple/1, c_tuple_skel/1,
fold_literal/1, is_literal/1.
See also: c_alias/2.
See also: c_apply/2.
See also: c_binary/1.
Equivalent to update_c_bitstr(Node, Value, Size, abstract(1), Type, Flags).
See also: c_bitstr/5, update_c_bitstr/5.
See also: c_call/3.
See also: c_case/2.
See also: c_catch/1.
See also: c_clause/3.
See also: c_cons/2.
See also: c_cons_skel/2.
Like update_c_fname/3, but takes the arity from Node.
See also: c_fname/2, update_c_fname/3.
Equivalent to update_c_var(Old, {Atom, Arity}).
See also: c_fname/2, update_c_fname/2.
See also: c_fun/2.
See also: c_let/3.
See also: c_letrec/2.
-spec update_c_map_pair(c_map_pair(), map_op(), cerl(), cerl()) -> c_map_pair().
-spec update_c_module(c_module(), cerl(), [cerl()], [{cerl(), cerl()}], [{cerl(), cerl()}]) -> c_module().
See also: c_module/4.
See also: c_primop/2.
See also: c_receive/3.
See also: c_seq/2.
See also: c_try/5.
See also: c_tuple/1.
See also: c_tuple_skel/1.
See also: c_values/1.
See also: c_var/1.
See also: make_data/2.
See also: make_data_skel/2.
Equivalent to update_list(Old, List, none).
See also: make_list/2, update_list/2.
Creates a syntax tree with the given subtrees, and the same type and annotations
as the Old node. This is equivalent to
ann_make_tree(get_ann(Node), type(Node), Groups), but
potentially more efficient.
See also: ann_make_tree/3, get_ann/1, type/1, update_tree/3.
Creates a syntax tree with the given type and subtrees, and the same annotations
as the Old node. This is equivalent to
ann_make_tree(get_ann(Node), Type, Groups), but
potentially more efficient.
See also: ann_make_tree/3, get_ann/1, update_tree/2.
-spec values_arity(c_values()) -> non_neg_integer().
Returns the number of element subtrees of an abstract value list.
Note: This is equivalent to length(values_es(Node)), but
potentially more efficient.
See also: c_values/1, values_es/1.
Returns the list of element subtrees of an abstract value list.
See also: c_values/1, values_arity/1.
Returns the name of an abstract variable.
See also: c_var/1.