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diff --git a/erts/doc/src/absform.xml b/erts/doc/src/absform.xml index 547d5e583d..e49c8c32e9 100644 --- a/erts/doc/src/absform.xml +++ b/erts/doc/src/absform.xml @@ -4,14 +4,14 @@ <chapter> <header> <copyright> - <year>2001</year><year>2015</year> + <year>2001</year><year>2017</year> <holder>Ericsson AB. All Rights Reserved.</holder> </copyright> <legalnotice> Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at - + http://www.apache.org/licenses/LICENSE-2.0 Unless required by applicable law or agreed to in writing, software @@ -19,614 +19,931 @@ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License. - + </legalnotice> <title>The Abstract Format</title> <prepared>Arndt Jonasson</prepared> <responsible>Kenneth Lundin</responsible> <docno>1</docno> - <approved>Jultomten</approved> + <approved></approved> <checked></checked> - <date>00-12-01</date> + <date>2000-12-01</date> <rev>A</rev> <file>absform.xml</file> </header> - <p></p> - <p>This document describes the standard representation of parse trees for Erlang - programs as Erlang terms. This representation is known as the <em>abstract format</em>. - Functions dealing with such parse trees are <c><![CDATA[compile:forms/[1,2]]]></c> - and functions in the modules - <c><![CDATA[epp]]></c>, - <c><![CDATA[erl_eval]]></c>, - <c><![CDATA[erl_lint]]></c>, - <c><![CDATA[erl_pp]]></c>, - <c><![CDATA[erl_parse]]></c>, - and - <c><![CDATA[io]]></c>. - They are also used as input and output for parse transforms (see the module - <c><![CDATA[compile]]></c>).</p> - <p>We use the function <c><![CDATA[Rep]]></c> to denote the mapping from an Erlang source - construct <c><![CDATA[C]]></c> to its abstract format representation <c><![CDATA[R]]></c>, and write - <c><![CDATA[R = Rep(C)]]></c>. - </p> - <p>The word <c><![CDATA[LINE]]></c> below represents an integer, and denotes the + <p>This section describes the standard representation of parse trees for Erlang + programs as Erlang terms. This representation is known as the <em>abstract + format</em>. Functions dealing with such parse trees are + <seealso marker="compiler:compile#forms/1"> + <c>compile:forms/1,2</c></seealso> and functions in the following + modules:</p> + + <list type="bulleted"> + <item><seealso marker="stdlib:epp"> + <c>epp(3)</c></seealso></item> + <item><seealso marker="stdlib:erl_eval"> + <c>erl_eval(3)</c></seealso></item> + <item><seealso marker="stdlib:erl_lint"> + <c>erl_lint(3)</c></seealso></item> + <item><seealso marker="stdlib:erl_parse"> + <c>erl_parse(3)</c></seealso></item> + <item><seealso marker="stdlib:erl_pp"> + <c>erl_pp(3)</c></seealso></item> + <item><seealso marker="stdlib:io"> + <c>io(3)</c></seealso></item> + </list> + + <p>The functions are also used as input and output for parse transforms, see + the <seealso marker="compiler:compile"><c>compile(3)</c></seealso> + module.</p> + + <p>We use the function <c>Rep</c> to denote the mapping from an Erlang source + construct <c>C</c> to its abstract format representation <c>R</c>, and write + <c>R = Rep(C)</c>.</p> + + <p>The word <c>LINE</c> in this section represents an integer, and denotes the number of the line in the source file where the construction occurred. - Several instances of <c><![CDATA[LINE]]></c> in the same construction may denote + Several instances of <c>LINE</c> in the same construction can denote different lines.</p> - <p>Since operators are not terms in their own right, when operators are - mentioned below, the representation of an operator should be taken to + + <p>As operators are not terms in their own right, when operators are + mentioned below, the representation of an operator is to be taken to be the atom with a printname consisting of the same characters as the - operator. - </p> + operator.</p> <section> - <title>Module declarations and forms</title> - <p>A module declaration consists of a sequence of forms that are either + <title>Module Declarations and Forms</title> + <p>A module declaration consists of a sequence of forms, which are either function declarations or attributes.</p> + <list type="bulleted"> - <item>If D is a module declaration consisting of the forms - <c><![CDATA[F_1]]></c>, ..., <c><![CDATA[F_k]]></c>, then - Rep(D) = <c><![CDATA[[Rep(F_1), ..., Rep(F_k)]]]></c>.</item> - <item>If F is an attribute <c><![CDATA[-module(Mod)]]></c>, then - Rep(F) = <c><![CDATA[{attribute,LINE,module,Mod}]]></c>.</item> - <item>If F is an attribute <c><![CDATA[-export([Fun_1/A_1, ..., Fun_k/A_k])]]></c>, then - Rep(F) = <c><![CDATA[{attribute,LINE,export,[{Fun_1,A_1}, ..., {Fun_k,A_k}]}]]></c>.</item> - <item>If F is an attribute <c><![CDATA[-import(Mod,[Fun_1/A_1, ..., Fun_k/A_k])]]></c>, then - Rep(F) = <c><![CDATA[{attribute,LINE,import,{Mod,[{Fun_1,A_1}, ..., {Fun_k,A_k}]}}]]></c>.</item> - <item>If F is an attribute <c><![CDATA[-compile(Options)]]></c>, then - Rep(F) = <c><![CDATA[{attribute,LINE,compile,Options}]]></c>.</item> - <item>If F is an attribute <c><![CDATA[-file(File,Line)]]></c>, then - Rep(F) = <c><![CDATA[{attribute,LINE,file,{File,Line}}]]></c>.</item> - <item>If F is a record declaration <c><![CDATA[-record(Name,{V_1, ..., V_k})]]></c>, then - Rep(F) = - <c><![CDATA[{attribute,LINE,record,{Name,[Rep(V_1), ..., Rep(V_k)]}}]]></c>. For Rep(V), see below.</item> - <item>If F is a type attribute (i.e. <c><![CDATA[opaque]]></c> or - <c><![CDATA[type]]></c>) - <c><![CDATA[-Attr Name(A_1, ..., A_k) :: T]]></c> where each - <c><![CDATA[A_i]]></c> is a variable, then Rep(F) = - <c><![CDATA[{attribute,LINE,Attr,{Name,Rep(T),[Rep(A_1), ..., Rep(A_k)]}}]]></c>. - For Rep(T), see below.</item> - <item>If F is a type spec (i.e. <c><![CDATA[callback]]></c> or - <c><![CDATA[spec]]></c>) - <c><![CDATA[-Attr F Tc_1; ...; Tc_k]]></c>, - where each <c><![CDATA[Tc_i]]></c> is a fun type clause with an - argument sequence of the same length <c><![CDATA[Arity]]></c>, then - Rep(F) = - <c><![CDATA[{Attr,LINE,{{F,Arity},[Rep(Tc_1), ..., Rep(Tc_k)]}}]]></c>. - For Rep(Tc_i), see below.</item> - <item>If F is a type spec (i.e. <c><![CDATA[callback]]></c> or - <c><![CDATA[spec]]></c>) - <c><![CDATA[-Attr Mod:F Tc_1; ...; Tc_k]]></c>, - where each <c><![CDATA[Tc_i]]></c> is a fun type clause with an - argument sequence of the same length <c><![CDATA[Arity]]></c>, then - Rep(F) = - <c><![CDATA[{Attr,LINE,{{Mod,F,Arity},[Rep(Tc_1), ..., Rep(Tc_k)]}}]]></c>. - For Rep(Tc_i), see below.</item> - <item>If F is a wild attribute <c><![CDATA[-A(T)]]></c>, then - Rep(F) = <c><![CDATA[{attribute,LINE,A,T}]]></c>. - <br></br></item> - <item>If F is a function declaration <c><![CDATA[Name Fc_1 ; ... ; Name Fc_k]]></c>, - where each <c><![CDATA[Fc_i]]></c> is a function clause with a - pattern sequence of the same length <c><![CDATA[Arity]]></c>, then - Rep(F) = <c><![CDATA[{function,LINE,Name,Arity,[Rep(Fc_1), ...,Rep(Fc_k)]}]]></c>.</item> + <item> + <p>If D is a module declaration consisting of the forms + <c>F_1</c>, ..., <c>F_k</c>, then + Rep(D) = <c>[Rep(F_1), ..., Rep(F_k)]</c>.</p> + </item> + <item> + <p>If F is an attribute <c>-export([Fun_1/A_1, ..., Fun_k/A_k])</c>, + then Rep(F) = + <c>{attribute,LINE,export,[{Fun_1,A_1}, ..., {Fun_k,A_k}]}</c>.</p> + </item> + <item> + <p>If F is an attribute <c>-import(Mod,[Fun_1/A_1, ..., Fun_k/A_k])</c>, + then Rep(F) = + <c>{attribute,LINE,import,{Mod,[{Fun_1,A_1}, ..., + {Fun_k,A_k}]}}</c>.</p> + </item> + <item> + <p>If F is an attribute <c>-module(Mod)</c>, then + Rep(F) = <c>{attribute,LINE,module,Mod}</c>.</p> + </item> + <item> + <p>If F is an attribute <c>-file(File,Line)</c>, then + Rep(F) = <c>{attribute,LINE,file,{File,Line}}</c>.</p> + </item> + <item> + <p>If F is a function declaration <c>Name Fc_1 ; ... ; Name Fc_k</c>, + where each <c>Fc_i</c> is a function clause with a pattern sequence of + the same length <c>Arity</c>, then Rep(F) = + <c>{function,LINE,Name,Arity,[Rep(Fc_1), ...,Rep(Fc_k)]}</c>.</p> + </item> + <item> + <p>If F is a function specification <c>-Spec Name Ft_1; ...; Ft_k</c>, + where <c>Spec</c> is either the atom <c>spec</c> or the atom + <c>callback</c>, and each <c>Ft_i</c> is a possibly constrained + function type with an argument sequence of the same length + <c>Arity</c>, then Rep(F) = + <c>{attribute,Line,Spec,{{Name,Arity},[Rep(Ft_1), ..., + Rep(Ft_k)]}}</c>.</p> + </item> + <item> + <p>If F is a function specification + <c>-spec Mod:Name Ft_1; ...; Ft_k</c>, where each <c>Ft_i</c> is a + possibly constrained function type with an argument sequence of the + same length <c>Arity</c>, then Rep(F) = + <c>{attribute,Line,spec,{{Mod,Name,Arity},[Rep(Ft_1), ..., + Rep(Ft_k)]}}</c>.</p> + </item> + <item> + <p>If F is a record declaration <c>-record(Name,{V_1, ..., V_k})</c>, + where each <c>V_i</c> is a record field, then Rep(F) = + <c>{attribute,LINE,record,{Name,[Rep(V_1), ..., Rep(V_k)]}}</c>. + For Rep(V), see below.</p> + </item> + <item> + <p>If F is a type declaration <c>-Type Name(V_1, ..., V_k) :: T</c>, + where <c>Type</c> is either the atom <c>type</c> or the atom + <c>opaque</c>, each <c>V_i</c> is a variable, and <c>T</c> is a type, + then Rep(F) = + <c>{attribute,LINE,Type,{Name,Rep(T),[Rep(V_1), ..., + Rep(V_k)]}}</c>.</p> + </item> + <item> + <p>If F is a wild attribute <c>-A(T)</c>, then + Rep(F) = <c>{attribute,LINE,A,T}</c>.</p> + </item> </list> <section> - <title>Type clauses</title> - <list type="bulleted"> - <item>If T is a fun type clause - <c><![CDATA[(A_1, ..., A_n) -> Ret]]></c>, where each - <c><![CDATA[A_i]]></c> and <c><![CDATA[Ret]]></c> are types, then - Rep(T) = - <c><![CDATA[{type,LINE,'fun',[{type,LINE,product,[Rep(A_1), ..., Rep(A_n)]},Rep(Ret)]}]]></c>. - </item> - <item>If T is a bounded fun type clause <c><![CDATA[Tc when Tg]]></c>, - where <c><![CDATA[Tc]]></c> is an unbounded fun type clause and - <c><![CDATA[Tg]]></c> is a type guard sequence, then Rep(T) = - <c><![CDATA[{type,LINE,bounded_fun,[Rep(Tc),Rep(Tg)]}]]></c>.</item> - </list> - </section> - - <section> - <title>Type guards</title> - <list type="bulleted"> - <item>If G is a constraint <c><![CDATA[F(A_1, ..., A_k)]]></c>, where - <c><![CDATA[F]]></c> is an atom and each <c><![CDATA[A_i]]></c> is a - type, then Rep(G) = - <c><![CDATA[{type,LINE,constraint,[Rep(F),[Rep(A_1), ..., Rep(A_k)]]}]]></c>. - </item> - <item>If G is a type definition <c><![CDATA[Name :: Type]]></c>, - where <c><![CDATA[Name]]></c> is a variable and - <c><![CDATA[Type]]></c> is a type, then Rep(G) = - <c><![CDATA[{type,LINE,constraint,[{atom,LINE,is_subtype},[Rep(Name),Rep(Type)]]}]]></c>.</item> - </list> - </section> + <title>Record Fields</title> + <p>Each field in a record declaration can have an optional, + explicit, default initializer expression, and an + optional type.</p> - <section> - <title>Types</title> <list type="bulleted"> - <item>If T is a type definition <c><![CDATA[Name :: Type]]></c>, - where <c><![CDATA[Name]]></c> is a variable and - <c><![CDATA[Type]]></c> is a type, then Rep(T) = - <c><![CDATA[{ann_type,LINE,[Rep(Name),Rep(Type)]}]]></c>.</item> - <item>If T is a type union <c><![CDATA[A_1 | ... | A_k]]></c>, - where each <c><![CDATA[A_i]]></c> is a type, then Rep(T) = - <c><![CDATA[{type,LINE,union,[Rep(A_1), ..., Rep(A_k)]}]]></c>.</item> - <item>If T is a type range <c><![CDATA[L .. R]]></c>, - where <c><![CDATA[L]]></c> and <c><![CDATA[R]]></c> are types, then - Rep(T) = <c><![CDATA[{type,LINE,range,[Rep(L), Rep(R)]}]]></c>.</item> - <item>If T is a binary operation <c><![CDATA[L Op R]]></c>, - where <c><![CDATA[Op]]></c> is an arithmetic or bitwise binary operator - and <c><![CDATA[L]]></c> and <c><![CDATA[R]]></c> are types, then - Rep(T) = <c><![CDATA[{op,LINE,Op,Rep(L),Rep(R)}]]></c>.</item> - <item>If T is <c><![CDATA[Op A]]></c>, where <c><![CDATA[Op]]></c> is an - arithmetic or bitwise unary operator and <c><![CDATA[A]]></c> is a - type, then Rep(T) = <c><![CDATA[{op,LINE,Op,Rep(A)}]]></c>.</item> - <item>If T is a fun type <c><![CDATA[fun()]]></c>, then Rep(T) = - <c><![CDATA[{type,LINE,'fun',[]}]]></c>.</item> - <item>If T is a variable <c><![CDATA[V]]></c>, then Rep(T) = - <c><![CDATA[{var,LINE,A}]]></c>, where <c><![CDATA[A]]></c> is an atom - with a printname consisting of the same characters as - <c><![CDATA[V]]></c>.</item> - <item>If T is an atomic literal L and L is not a string literal, then - Rep(T) = Rep(L).</item> - <item>If T is a tuple or map type <c><![CDATA[F()]]></c> (i.e. - <c><![CDATA[tuple]]></c> or <c><![CDATA[map]]></c>), then Rep(T) = - <c><![CDATA[{type,LINE,F,any}]]></c>.</item> - <item>If T is a type <c><![CDATA[F(A_1, ..., A_k)]]></c>, where each - <c><![CDATA[A_i]]></c> is a type, then Rep(T) = - <c><![CDATA[{user_type,LINE,F,[Rep(A_1), ..., Rep(A_k)]}]]></c>.</item> - <item>If T is a remote type <c><![CDATA[M:F(A_1, ..., A_k)]]></c>, where - each <c><![CDATA[A_i]]></c> is a type and <c><![CDATA[M]]></c> and - <c><![CDATA[F]]></c>, then Rep(T) = - <c><![CDATA[{remote_type,LINE,[Rep(M),Rep(F),[Rep(A_1), ..., Rep(A_k)]]}]]></c>. + <item> + <p>If V is <c>A</c>, then + Rep(V) = <c>{record_field,LINE,Rep(A)}</c>.</p> </item> - <item>If T is the nil type <c><![CDATA[[]]]></c>, then Rep(T) = - <c><![CDATA[{type,LINE,nil,[]}]]></c>.</item> - <item>If T is a list type <c><![CDATA[[A]]]></c>, where - <c><![CDATA[A]]></c> is a type, then Rep(T) = - <c><![CDATA[{type,LINE,list,[Rep(A)]}]]></c>.</item> - <item>If T is a non-empty list type <c><![CDATA[[A, ...]]]></c>, where - <c><![CDATA[A]]></c> is a type, then Rep(T) = - <c><![CDATA[{type,LINE,nonempty_list,[Rep(A)]}]]></c>.</item> - <item>If T is a map type <c><![CDATA[#{P_1, ..., P_k}]]></c>, where each - <c><![CDATA[P_i]]></c> is a map pair type, then Rep(T) = - <c><![CDATA[{type,LINE,map,[Rep(P_1), ..., Rep(P_k)]}]]></c>.</item> - <item>If T is a map pair type <c><![CDATA[K => V]]></c>, where - <c><![CDATA[K]]></c> and <c><![CDATA[V]]></c> are types, - then Rep(T) = - <c><![CDATA[{type,LINE,map_field_assoc,[Rep(K),Rep(V)]}]]></c>.</item> - <item>If T is a tuple type <c><![CDATA[{A_1, ..., A_k}]]></c>, where - each <c><![CDATA[A_i]]></c> is a type, then Rep(T) = - <c><![CDATA[{type,LINE,tuple,[Rep(A_1), ..., Rep(A_k)]}]]></c>.</item> - <item>If T is a record type <c><![CDATA[#Name{}]]></c>, where - <c><![CDATA[Name]]></c> is an atom, then Rep(T) = - <c><![CDATA[{type,LINE,record,[Rep(Name)]}]]></c>.</item> - <item>If T is a record type <c><![CDATA[#Name{F_1, ..., F_k}]]></c>, - where <c><![CDATA[Name]]></c> is an atom, then Rep(T) = - <c><![CDATA[{type,LINE,record,[Rep(Name),[Rep(F_1), ..., Rep(F_k)]]}]]></c>. + <item> + <p>If V is <c>A = E</c>, where <c>E</c> is an expression, then + Rep(V) = <c>{record_field,LINE,Rep(A),Rep(E)}</c>.</p> </item> - <item>If T is a record field type <c><![CDATA[Name :: Type]]></c>, - where <c><![CDATA[Name]]></c> is an atom, then Rep(T) = - <c><![CDATA[{type,LINE,field_type,[Rep(Name),Rep(Type)]}]]></c>.</item> - <item>If T is a record field type <c><![CDATA[<<>>]]></c>, then Rep(T) = - <c><![CDATA[{type,LINE,binary,[{integer,LINE,0},{integer,LINE,0}]}]]></c>. + <item> + <p>If V is <c>A :: T</c>, where <c>T</c> is a type, then Rep(V) = + <c>{typed_record_field,{record_field,LINE,Rep(A)},Rep(T)}</c>.</p> </item> - <item>If T is a binary type <c><![CDATA[<< _ : B >>]]></c>, where - <c><![CDATA[B]]></c> is a type, then Rep(T) = - <c><![CDATA[{type,LINE,binary,[Rep(B),{integer,LINE,0}]}]]></c>.</item> - <item>If T is a binary type <c><![CDATA[<< _ : _ * U >>]]></c>, - where <c><![CDATA[U]]></c> is a type, then Rep(T) = - <c><![CDATA[{type,LINE,binary,[{integer,LINE,0},Rep(U)]}]]></c>.</item> - <item>If T is a binary type <c><![CDATA[<< _ : B , _ : _ * U >>]]></c>, - where <c><![CDATA[B]]></c> and <c><![CDATA[U]]></c> is a type, then - Rep(T) = - <c><![CDATA[{type,LINE,binary,[Rep(B),Rep(U)]}]]></c>.</item> - - <item>If T is a fun type <c><![CDATA[fun((...) -> Ret)]]></c>, then - Rep(T) = <c><![CDATA[{type,LINE,'fun',[{type,LINE,product,[]},Rep(Ret)]}]]></c>. + <item> + <p>If V is <c>A = E :: T</c>, where + <c>E</c> is an expression and <c>T</c> is a type, then Rep(V) = + <c>{typed_record_field,{record_field,LINE,Rep(A),Rep(E)},Rep(T)}</c>. + </p> </item> - <item>If T is a fun type <c><![CDATA[fun(Tc)]]></c>, where - <c><![CDATA[Tc]]></c> is an unbounded fun type clause, - then Rep(T) = <c><![CDATA[Rep(Tc)]]></c>.</item> </list> </section> <section> - <title>Record fields</title> - <p>Each field in a record declaration may have an optional - explicit default initializer expression</p> + <title>Representation of Parse Errors and End-of-File</title> + <p>In addition to the representations of forms, the list that represents + a module declaration (as returned by functions in + <seealso marker="stdlib:epp"><c>epp(3)</c></seealso> and + <seealso marker="stdlib:erl_parse"><c>erl_parse(3)</c></seealso>) + can contain the following:</p> + <list type="bulleted"> - <item>If V is <c><![CDATA[A]]></c>, then - Rep(V) = <c><![CDATA[{record_field,LINE,Rep(A)}]]></c>.</item> - <item>If V is <c><![CDATA[A = E]]></c>, then - Rep(V) = <c><![CDATA[{record_field,LINE,Rep(A),Rep(E)}]]></c>.</item> - <item>If V is <c><![CDATA[A :: T]]></c>, where <c><![CDATA[A]]></c> is - an atom and <c><![CDATA[T]]></c> is a type and it does not contain - <c><![CDATA[undefined]]></c> syntactically, then Rep(V) = - <c><![CDATA[{typed_record_field,{record_field,LINE,Rep(A)},Rep(undefined | T)}]]></c>. - Note that if <![CDATA[T]]> is an annotated type, it will be wrapped in - parentheses.</item> - <item>If V is <c><![CDATA[A :: T]]></c>, where <c><![CDATA[A]]></c> is - an atom and <c><![CDATA[T]]></c> is a type, then Rep(V) = - <c><![CDATA[{typed_record_field,{record_field,LINE,Rep(A)},Rep(T)}]]></c>. - </item> - <item>If V is <c><![CDATA[A = E :: T]]></c>, where <c><![CDATA[A]]></c> - is an atom, <c><![CDATA[E]]></c> is an expression and - <c><![CDATA[T]]></c> is a type, then Rep(V) = - <c><![CDATA[{typed_record_field,{record_field,LINE,Rep(A),Rep(E)},Rep(T)}]]></c>. - </item> + <item> + <p>Tuples <c>{error,E}</c> and <c>{warning,W}</c>, denoting + syntactically incorrect forms and warnings. + </p> + </item> + <item> + <p><c>{eof,LOCATION}</c>, denoting an end-of-stream + encountered before a complete form had been parsed. + The word <c>LOCATION</c> represents an integer, and denotes the + number of the last line in the source file. + </p> + </item> </list> </section> - - <section> - <title>Representation of parse errors and end of file</title> - <p>In addition to the representations of forms, the list that represents - a module declaration (as returned by functions in <c><![CDATA[erl_parse]]></c> and - <c><![CDATA[epp]]></c>) may contain tuples <c><![CDATA[{error,E}]]></c> and <c><![CDATA[{warning,W}]]></c>, denoting - syntactically incorrect forms and warnings, and <c><![CDATA[{eof,LINE}]]></c>, denoting an end - of stream encountered before a complete form had been parsed.</p> - </section> </section> <section> - <title>Atomic literals</title> + <title>Atomic Literals</title> <p>There are five kinds of atomic literals, which are represented in the - same way in patterns, expressions and guards:</p> + same way in patterns, expressions, and guards:</p> + <list type="bulleted"> - <item>If L is an integer or character literal, then - Rep(L) = <c><![CDATA[{integer,LINE,L}]]></c>.</item> - <item>If L is a float literal, then - Rep(L) = <c><![CDATA[{float,LINE,L}]]></c>.</item> - <item>If L is a string literal consisting of the characters - <c><![CDATA[C_1]]></c>, ..., <c><![CDATA[C_k]]></c>, then - Rep(L) = <c><![CDATA[{string,LINE,[C_1, ..., C_k]}]]></c>.</item> - <item>If L is an atom literal, then - Rep(L) = <c><![CDATA[{atom,LINE,L}]]></c>.</item> + <item> + <p>If L is an atom literal, then Rep(L) = <c>{atom,LINE,L}</c>.</p> + </item> + <item> + <p>If L is a character literal, then Rep(L) = <c>{char,LINE,L}</c>.</p> + </item> + <item> + <p>If L is a float literal, then Rep(L) = <c>{float,LINE,L}</c>.</p> + </item> + <item> + <p>If L is an integer literal, then + Rep(L) = <c>{integer,LINE,L}</c>.</p> + </item> + <item> + <p>If L is a string literal consisting of the characters + <c>C_1</c>, ..., <c>C_k</c>, then + Rep(L) = <c>{string,LINE,[C_1, ..., C_k]}</c>.</p> + </item> </list> - <p>Note that negative integer and float literals do not occur as such; they are - parsed as an application of the unary negation operator.</p> + + <p>Notice that negative integer and float literals do not occur as such; + they are parsed as an application of the unary negation operator.</p> </section> <section> <title>Patterns</title> - <p>If <c><![CDATA[Ps]]></c> is a sequence of patterns <c><![CDATA[P_1, ..., P_k]]></c>, then - Rep(Ps) = <c><![CDATA[[Rep(P_1), ..., Rep(P_k)]]]></c>. Such sequences occur as the + <p>If Ps is a sequence of patterns <c>P_1, ..., P_k</c>, then + Rep(Ps) = <c>[Rep(P_1), ..., Rep(P_k)]</c>. Such sequences occur as the list of arguments to a function or fun.</p> + <p>Individual patterns are represented as follows:</p> + <list type="bulleted"> - <item>If P is an atomic literal L, then Rep(P) = Rep(L).</item> - <item>If P is a compound pattern <c><![CDATA[P_1 = P_2]]></c>, then - Rep(P) = <c><![CDATA[{match,LINE,Rep(P_1),Rep(P_2)}]]></c>.</item> - <item>If P is a variable pattern <c><![CDATA[V]]></c>, then - Rep(P) = <c><![CDATA[{var,LINE,A}]]></c>, - where A is an atom with a printname consisting of the same characters as - <c><![CDATA[V]]></c>.</item> - <item>If P is a universal pattern <c><![CDATA[_]]></c>, then - Rep(P) = <c><![CDATA[{var,LINE,'_'}]]></c>.</item> - <item>If P is a tuple pattern <c><![CDATA[{P_1, ..., P_k}]]></c>, then - Rep(P) = <c><![CDATA[{tuple,LINE,[Rep(P_1), ..., Rep(P_k)]}]]></c>.</item> - <item>If P is a nil pattern <c><![CDATA[[]]]></c>, then - Rep(P) = <c><![CDATA[{nil,LINE}]]></c>.</item> - <item>If P is a cons pattern <c><![CDATA[[P_h | P_t]]]></c>, then - Rep(P) = <c><![CDATA[{cons,LINE,Rep(P_h),Rep(P_t)}]]></c>.</item> - <item>If E is a binary pattern <c><![CDATA[<<P_1:Size_1/TSL_1, ..., P_k:Size_k/TSL_k>>]]></c>, then - Rep(E) = <c><![CDATA[{bin,LINE,[{bin_element,LINE,Rep(P_1),Rep(Size_1),Rep(TSL_1)}, ..., {bin_element,LINE,Rep(P_k),Rep(Size_k),Rep(TSL_k)}]}]]></c>. - For Rep(TSL), see below. - An omitted <c><![CDATA[Size]]></c> is represented by <c><![CDATA[default]]></c>. An omitted <c><![CDATA[TSL]]></c> - (type specifier list) is represented by <c><![CDATA[default]]></c>.</item> - <item>If P is <c><![CDATA[P_1 Op P_2]]></c>, where <c><![CDATA[Op]]></c> is a binary operator (this - is either an occurrence of <c><![CDATA[++]]></c> applied to a literal string or character - list, or an occurrence of an expression that can be evaluated to a number - at compile time), - then Rep(P) = <c><![CDATA[{op,LINE,Op,Rep(P_1),Rep(P_2)}]]></c>.</item> - <item>If P is <c><![CDATA[Op P_0]]></c>, where <c><![CDATA[Op]]></c> is a unary operator (this is an - occurrence of an expression that can be evaluated to a number at compile - time), then Rep(P) = <c><![CDATA[{op,LINE,Op,Rep(P_0)}]]></c>.</item> - <item>If P is a record pattern <c><![CDATA[#Name{Field_1=P_1, ..., Field_k=P_k}]]></c>, - then Rep(P) = - <c><![CDATA[{record,LINE,Name, [{record_field,LINE,Rep(Field_1),Rep(P_1)}, ..., {record_field,LINE,Rep(Field_k),Rep(P_k)}]}]]></c>.</item> - <item>If P is <c><![CDATA[#Name.Field]]></c>, then - Rep(P) = <c><![CDATA[{record_index,LINE,Name,Rep(Field)}]]></c>.</item> - <item>If P is <c><![CDATA[( P_0 )]]></c>, then - Rep(P) = <c><![CDATA[Rep(P_0)]]></c>, - i.e., patterns cannot be distinguished from their bodies.</item> + <item> + <p>If P is an atomic literal <c>L</c>, then Rep(P) = Rep(L).</p> + </item> + <item> + <p>If P is a bitstring pattern + <c><<P_1:Size_1/TSL_1, ..., P_k:Size_k/TSL_k>></c>, where each + <c>Size_i</c> is an expression that can be evaluated to an integer, + and each <c>TSL_i</c> is a type specificer list, then Rep(P) = + <c>{bin,LINE,[{bin_element,LINE,Rep(P_1),Rep(Size_1),Rep(TSL_1)}, + ..., {bin_element,LINE,Rep(P_k),Rep(Size_k),Rep(TSL_k)}]}</c>. + For Rep(TSL), see below. + An omitted <c>Size_i</c> is represented by <c>default</c>. + An omitted <c>TSL_i</c> is represented by <c>default</c>.</p> + </item> + <item> + <p>If P is a compound pattern <c>P_1 = P_2</c>, then Rep(P) = + <c>{match,LINE,Rep(P_1),Rep(P_2)}</c>.</p> + </item> + <item> + <p>If P is a cons pattern <c>[P_h | P_t]</c>, then Rep(P) = + <c>{cons,LINE,Rep(P_h),Rep(P_t)}</c>.</p> + </item> + <item> + <p>If P is a map pattern <c>#{A_1, ..., A_k}</c>, where each + <c>A_i</c> is an association <c>P_i_1 := P_i_2</c>, then Rep(P) = + <c>{map,LINE,[Rep(A_1), ..., Rep(A_k)]}</c>. + For Rep(A), see below.</p> + </item> + <item> + <p>If P is a nil pattern <c>[]</c>, then Rep(P) = + <c>{nil,LINE}</c>.</p> + </item> + <item> + <p>If P is an operator pattern <c>P_1 Op P_2</c>, where <c>Op</c> is a + binary operator (this is either an occurrence of <c>++</c> applied to + a literal string or character list, or an occurrence of an expression + that can be evaluated to a number at compile time), then Rep(P) = + <c>{op,LINE,Op,Rep(P_1),Rep(P_2)}</c>.</p> + </item> + <item> + <p>If P is an operator pattern <c>Op P_0</c>, where <c>Op</c> is a + unary operator (this is an occurrence of an expression that can be + evaluated to a number at compile time), then Rep(P) = + <c>{op,LINE,Op,Rep(P_0)}</c>.</p> + </item> + <item> + <p>If P is a parenthesized pattern <c>( P_0 )</c>, then Rep(P) = + <c>Rep(P_0)</c>, that is, parenthesized patterns cannot be + distinguished from their bodies.</p> + </item> + <item> + <p>If P is a record field index pattern <c>#Name.Field</c>, + where <c>Field</c> is an atom, then Rep(P) = + <c>{record_index,LINE,Name,Rep(Field)}</c>.</p> + </item> + <item> + <p>If P is a record pattern <c>#Name{Field_1=P_1, ..., Field_k=P_k}</c>, + where each <c>Field_i</c> is an atom or <c>_</c>, then Rep(P) = + <c>{record,LINE,Name,[{record_field,LINE,Rep(Field_1),Rep(P_1)}, ..., + {record_field,LINE,Rep(Field_k),Rep(P_k)}]}</c>.</p> + </item> + <item> + <p>If P is a tuple pattern <c>{P_1, ..., P_k}</c>, then Rep(P) = + <c>{tuple,LINE,[Rep(P_1), ..., Rep(P_k)]}</c>.</p> + </item> + <item> + <p>If P is a universal pattern <c>_</c>, then Rep(P) = + <c>{var,LINE,'_'}</c>.</p></item> + <item> + <p>If P is a variable pattern <c>V</c>, then Rep(P) = + <c>{var,LINE,A}</c>, where A is an atom with a printname consisting + of the same characters as <c>V</c>.</p> + </item> </list> - <p>Note that every pattern has the same source form as some expression, and is - represented the same way as the corresponding expression.</p> + + <p>Notice that every pattern has the same source form as some expression, + and is represented in the same way as the corresponding expression.</p> </section> <section> <title>Expressions</title> - <p>A body B is a sequence of expressions <c><![CDATA[E_1, ..., E_k]]></c>, and - Rep(B) = <c><![CDATA[[Rep(E_1), ..., Rep(E_k)]]]></c>.</p> - <p>An expression E is one of the following alternatives:</p> + <p>A body B is a non-empty sequence of expressions <c>E_1, ..., E_k</c>, + and Rep(B) = <c>[Rep(E_1), ..., Rep(E_k)]</c>.</p> + + <p>An expression E is one of the following:</p> + <list type="bulleted"> - <item>If P is an atomic literal <c><![CDATA[L]]></c>, then - Rep(P) = Rep(L).</item> - <item>If E is <c><![CDATA[P = E_0]]></c>, then - Rep(E) = <c><![CDATA[{match,LINE,Rep(P),Rep(E_0)}]]></c>.</item> - <item>If E is a variable <c><![CDATA[V]]></c>, then - Rep(E) = <c><![CDATA[{var,LINE,A}]]></c>, - where <c><![CDATA[A]]></c> is an atom with a printname consisting of the same - characters as <c><![CDATA[V]]></c>.</item> - <item>If E is a tuple skeleton <c><![CDATA[{E_1, ..., E_k}]]></c>, then - Rep(E) = <c><![CDATA[{tuple,LINE,[Rep(E_1), ..., Rep(E_k)]}]]></c>.</item> - <item>If E is <c><![CDATA[[]]]></c>, then - Rep(E) = <c><![CDATA[{nil,LINE}]]></c>.</item> - <item>If E is a cons skeleton <c><![CDATA[[E_h | E_t]]]></c>, then - Rep(E) = <c><![CDATA[{cons,LINE,Rep(E_h),Rep(E_t)}]]></c>.</item> - <item>If E is a binary constructor <c><![CDATA[<<V_1:Size_1/TSL_1, ..., V_k:Size_k/TSL_k>>]]></c>, then - Rep(E) = <c><![CDATA[{bin,LINE,[{bin_element,LINE,Rep(V_1),Rep(Size_1),Rep(TSL_1)}, ..., {bin_element,LINE,Rep(V_k),Rep(Size_k),Rep(TSL_k)}]}]]></c>. - For Rep(TSL), see below. - An omitted <c><![CDATA[Size]]></c> is represented by <c><![CDATA[default]]></c>. An omitted <c><![CDATA[TSL]]></c> - (type specifier list) is represented by <c><![CDATA[default]]></c>.</item> - <item>If E is <c><![CDATA[E_1 Op E_2]]></c>, where <c><![CDATA[Op]]></c> is a binary operator, - then Rep(E) = <c><![CDATA[{op,LINE,Op,Rep(E_1),Rep(E_2)}]]></c>.</item> - <item>If E is <c><![CDATA[Op E_0]]></c>, where <c><![CDATA[Op]]></c> is a unary operator, then - Rep(E) = <c><![CDATA[{op,LINE,Op,Rep(E_0)}]]></c>.</item> - <item>If E is <c><![CDATA[#Name{Field_1=E_1, ..., Field_k=E_k}]]></c>, then - Rep(E) = - <c><![CDATA[{record,LINE,Name, [{record_field,LINE,Rep(Field_1),Rep(E_1)}, ..., {record_field,LINE,Rep(Field_k),Rep(E_k)}]}]]></c>.</item> - <item>If E is <c><![CDATA[E_0#Name{Field_1=E_1, ..., Field_k=E_k}]]></c>, then - Rep(E) = - <c><![CDATA[{record,LINE,Rep(E_0),Name, [{record_field,LINE,Rep(Field_1),Rep(E_1)}, ..., {record_field,LINE,Rep(Field_k),Rep(E_k)}]}]]></c>.</item> - <item>If E is <c><![CDATA[#Name.Field]]></c>, then - Rep(E) = <c><![CDATA[{record_index,LINE,Name,Rep(Field)}]]></c>.</item> - <item>If E is <c><![CDATA[E_0#Name.Field]]></c>, then - Rep(E) = <c><![CDATA[{record_field,LINE,Rep(E_0),Name,Rep(Field)}]]></c>.</item> - <item>If E is <c><![CDATA[#{W_1, ..., W_k}]]></c> where each - <c><![CDATA[W_i]]></c> is a map assoc or exact field, then Rep(E) = - <c><![CDATA[{map,LINE,[Rep(W_1), ..., Rep(W_k)]}]]></c>. For Rep(W), see - below.</item> - <item>If E is <c><![CDATA[E_0#{W_1, ..., W_k}]]></c> where - <c><![CDATA[W_i]]></c> is a map assoc or exact field, then Rep(E) = - <c><![CDATA[{map,LINE,Rep(E_0),[Rep(W_1), ..., Rep(W_k)]}]]></c>. For - Rep(W), see below.</item> - <item>If E is <c><![CDATA[catch E_0]]></c>, then - Rep(E) = <c><![CDATA[{'catch',LINE,Rep(E_0)}]]></c>.</item> - <item>If E is <c><![CDATA[E_0(E_1, ..., E_k)]]></c>, then - Rep(E) = <c><![CDATA[{call,LINE,Rep(E_0),[Rep(E_1), ..., Rep(E_k)]}]]></c>.</item> - <item>If E is <c><![CDATA[E_m:E_0(E_1, ..., E_k)]]></c>, then - Rep(E) = - <c><![CDATA[{call,LINE,{remote,LINE,Rep(E_m),Rep(E_0)},[Rep(E_1), ..., Rep(E_k)]}]]></c>.</item> - <item>If E is a list comprehension <c><![CDATA[[E_0 || W_1, ..., W_k]]]></c>, - where each <c><![CDATA[W_i]]></c> is a generator or a filter, then - Rep(E) = <c><![CDATA[{lc,LINE,Rep(E_0),[Rep(W_1), ..., Rep(W_k)]}]]></c>. For Rep(W), see - below.</item> - <item>If E is a binary comprehension <c><![CDATA[<<E_0 || W_1, ..., W_k>>]]></c>, - where each <c><![CDATA[W_i]]></c> is a generator or a filter, then - Rep(E) = <c><![CDATA[{bc,LINE,Rep(E_0),[Rep(W_1), ..., Rep(W_k)]}]]></c>. For Rep(W), see - below.</item> - <item>If E is <c><![CDATA[begin B end]]></c>, where <c><![CDATA[B]]></c> is a body, then - Rep(E) = <c><![CDATA[{block,LINE,Rep(B)}]]></c>.</item> - <item>If E is <c><![CDATA[if Ic_1 ; ... ; Ic_k end]]></c>, - where each <c><![CDATA[Ic_i]]></c> is an if clause then - Rep(E) = - <c><![CDATA[{'if',LINE,[Rep(Ic_1), ..., Rep(Ic_k)]}]]></c>.</item> - <item>If E is <c><![CDATA[case E_0 of Cc_1 ; ... ; Cc_k end]]></c>, - where <c><![CDATA[E_0]]></c> is an expression and each <c><![CDATA[Cc_i]]></c> is a - case clause then - Rep(E) = - <c><![CDATA[{'case',LINE,Rep(E_0),[Rep(Cc_1), ..., Rep(Cc_k)]}]]></c>.</item> - <item>If E is <c><![CDATA[try B catch Tc_1 ; ... ; Tc_k end]]></c>, - where <c><![CDATA[B]]></c> is a body and each <c><![CDATA[Tc_i]]></c> is a catch clause then - Rep(E) = - <c><![CDATA[{'try',LINE,Rep(B),[],[Rep(Tc_1), ..., Rep(Tc_k)],[]}]]></c>.</item> - <item>If E is <c><![CDATA[try B of Cc_1 ; ... ; Cc_k catch Tc_1 ; ... ; Tc_n end]]></c>, - where <c><![CDATA[B]]></c> is a body, - each <c><![CDATA[Cc_i]]></c> is a case clause and - each <c><![CDATA[Tc_j]]></c> is a catch clause then - Rep(E) = - <c><![CDATA[{'try',LINE,Rep(B),[Rep(Cc_1), ..., Rep(Cc_k)],[Rep(Tc_1), ..., Rep(Tc_n)],[]}]]></c>.</item> - <item>If E is <c><![CDATA[try B after A end]]></c>, - where <c><![CDATA[B]]></c> and <c><![CDATA[A]]></c> are bodies then - Rep(E) = - <c><![CDATA[{'try',LINE,Rep(B),[],[],Rep(A)}]]></c>.</item> - <item>If E is <c><![CDATA[try B of Cc_1 ; ... ; Cc_k after A end]]></c>, - where <c><![CDATA[B]]></c> and <c><![CDATA[A]]></c> are a bodies and - each <c><![CDATA[Cc_i]]></c> is a case clause then - Rep(E) = - <c><![CDATA[{'try',LINE,Rep(B),[Rep(Cc_1), ..., Rep(Cc_k)],[],Rep(A)}]]></c>.</item> - <item>If E is <c><![CDATA[try B catch Tc_1 ; ... ; Tc_k after A end]]></c>, - where <c><![CDATA[B]]></c> and <c><![CDATA[A]]></c> are bodies and - each <c><![CDATA[Tc_i]]></c> is a catch clause then - Rep(E) = - <c><![CDATA[{'try',LINE,Rep(B),[],[Rep(Tc_1), ..., Rep(Tc_k)],Rep(A)}]]></c>.</item> - <item>If E is <c><![CDATA[try B of Cc_1 ; ... ; Cc_k catch Tc_1 ; ... ; Tc_n after A end]]></c>, - where <c><![CDATA[B]]></c> and <c><![CDATA[A]]></c> are a bodies, - each <c><![CDATA[Cc_i]]></c> is a case clause and - each <c><![CDATA[Tc_j]]></c> is a catch clause then - Rep(E) = - <c><![CDATA[{'try',LINE,Rep(B),[Rep(Cc_1), ..., Rep(Cc_k)],[Rep(Tc_1), ..., Rep(Tc_n)],Rep(A)}]]></c>.</item> - <item>If E is <c><![CDATA[receive Cc_1 ; ... ; Cc_k end]]></c>, - where each <c><![CDATA[Cc_i]]></c> is a case clause then - Rep(E) = - <c><![CDATA[{'receive',LINE,[Rep(Cc_1), ..., Rep(Cc_k)]}]]></c>.</item> - <item>If E is <c><![CDATA[receive Cc_1 ; ... ; Cc_k after E_0 -> B_t end]]></c>, - where each <c><![CDATA[Cc_i]]></c> is a case clause, - <c><![CDATA[E_0]]></c> is an expression and <c><![CDATA[B_t]]></c> is a body, then - Rep(E) = - <c><![CDATA[{'receive',LINE,[Rep(Cc_1), ..., Rep(Cc_k)],Rep(E_0),Rep(B_t)}]]></c>.</item> - <item>If E is <c><![CDATA[fun Name / Arity]]></c>, then - Rep(E) = <c><![CDATA[{'fun',LINE,{function,Name,Arity}}]]></c>.</item> - <item>If E is <c><![CDATA[fun Module:Name/Arity]]></c>, then - Rep(E) = <c><![CDATA[{'fun',LINE,{function,Rep(Module),Rep(Name),Rep(Arity)}}]]></c>. - (Before the R15 release: Rep(E) = <c><![CDATA[{'fun',LINE,{function,Module,Name,Arity}}]]></c>.)</item> - <item>If E is <c><![CDATA[fun Fc_1 ; ... ; Fc_k end]]></c> - where each <c><![CDATA[Fc_i]]></c> is a function clause then Rep(E) = - <c><![CDATA[{'fun',LINE,{clauses,[Rep(Fc_1), ..., Rep(Fc_k)]}}]]></c>.</item> - <item>If E is <c><![CDATA[fun Name Fc_1 ; ... ; Name Fc_k end]]></c> - where <c><![CDATA[Name]]></c> is a variable and each - <c><![CDATA[Fc_i]]></c> is a function clause then Rep(E) = - <c><![CDATA[{named_fun,LINE,Name,[Rep(Fc_1), ..., Rep(Fc_k)]}]]></c>. - </item> - <item>If E is <c><![CDATA[query [E_0 || W_1, ..., W_k] end]]></c>, - where each <c><![CDATA[W_i]]></c> is a generator or a filter, then - Rep(E) = <c><![CDATA[{'query',LINE,{lc,LINE,Rep(E_0),[Rep(W_1), ..., Rep(W_k)]}}]]></c>. - For Rep(W), see below.</item> - <item>If E is <c><![CDATA[E_0.Field]]></c>, a Mnesia record access - inside a query, then - Rep(E) = <c><![CDATA[{record_field,LINE,Rep(E_0),Rep(Field)}]]></c>.</item> - <item>If E is <c><![CDATA[( E_0 )]]></c>, then - Rep(E) = <c><![CDATA[Rep(E_0)]]></c>, - i.e., parenthesized expressions cannot be distinguished from their bodies.</item> + <item> + <p>If E is an atomic literal <c>L</c>, then Rep(E) = Rep(L).</p> + </item> + <item> + <p>If E is a bitstring comprehension + <c><<E_0 || Q_1, ..., Q_k>></c>, + where each <c>Q_i</c> is a qualifier, then Rep(E) = + <c>{bc,LINE,Rep(E_0),[Rep(Q_1), ..., Rep(Q_k)]}</c>. + For Rep(Q), see below.</p> + </item> + <item> + <p>If E is a bitstring constructor + <c><<E_1:Size_1/TSL_1, ..., E_k:Size_k/TSL_k>></c>, + where each <c>Size_i</c> is an expression and each + <c>TSL_i</c> is a type specificer list, then Rep(E) = + <c>{bin,LINE,[{bin_element,LINE,Rep(E_1),Rep(Size_1),Rep(TSL_1)}, + ..., {bin_element,LINE,Rep(E_k),Rep(Size_k),Rep(TSL_k)}]}</c>. + For Rep(TSL), see below. + An omitted <c>Size_i</c> is represented by <c>default</c>. + An omitted <c>TSL_i</c> is represented by <c>default</c>.</p> + </item> + <item> + <p>If E is a block expression <c>begin B end</c>, + where <c>B</c> is a body, then Rep(E) = + <c>{block,LINE,Rep(B)}</c>.</p> + </item> + <item> + <p>If E is a case expression <c>case E_0 of Cc_1 ; ... ; Cc_k end</c>, + where <c>E_0</c> is an expression and each <c>Cc_i</c> is a + case clause, then Rep(E) = + <c>{'case',LINE,Rep(E_0),[Rep(Cc_1), ..., Rep(Cc_k)]}</c>.</p> + </item> + <item> + <p>If E is a catch expression <c>catch E_0</c>, then Rep(E) = + <c>{'catch',LINE,Rep(E_0)}</c>.</p> + </item> + <item> + <p>If E is a cons skeleton <c>[E_h | E_t]</c>, then Rep(E) = + <c>{cons,LINE,Rep(E_h),Rep(E_t)}</c>.</p> + </item> + <item> + <p>If E is a fun expression <c>fun Name/Arity</c>, then Rep(E) = + <c>{'fun',LINE,{function,Name,Arity}}</c>.</p> + </item> + <item> + <p>If E is a fun expression <c>fun Module:Name/Arity</c>, then Rep(E) = + <c>{'fun',LINE,{function,Rep(Module),Rep(Name),Rep(Arity)}}</c>. + (Before Erlang/OTP R15: Rep(E) = + <c>{'fun',LINE,{function,Module,Name,Arity}}</c>.)</p> + </item> + <item> + <p>If E is a fun expression <c>fun Fc_1 ; ... ; Fc_k end</c>, + where each <c>Fc_i</c> is a function clause, then Rep(E) = + <c>{'fun',LINE,{clauses,[Rep(Fc_1), ..., Rep(Fc_k)]}}</c>.</p> + </item> + <item> + <p>If E is a fun expression <c>fun Name Fc_1 ; ... ; Name Fc_k end</c>, + where <c>Name</c> is a variable and each + <c>Fc_i</c> is a function clause, then Rep(E) = + <c>{named_fun,LINE,Name,[Rep(Fc_1), ..., Rep(Fc_k)]}</c>.</p> + </item> + <item> + <p>If E is a function call <c>E_0(E_1, ..., E_k)</c>, then Rep(E) = + <c>{call,LINE,Rep(E_0),[Rep(E_1), ..., Rep(E_k)]}</c>.</p> + </item> + <item> + <p>If E is a function call <c>E_m:E_0(E_1, ..., E_k)</c>, then Rep(E) = + <c>{call,LINE,{remote,LINE,Rep(E_m),Rep(E_0)},[Rep(E_1), ..., + Rep(E_k)]}</c>.</p> + </item> + <item> + <p>If E is an if expression <c>if Ic_1 ; ... ; Ic_k end</c>, + where each <c>Ic_i</c> is an if clause, then Rep(E) = + <c>{'if',LINE,[Rep(Ic_1), ..., Rep(Ic_k)]}</c>.</p> + </item> + <item> + <p>If E is a list comprehension <c>[E_0 || Q_1, ..., Q_k]</c>, + where each <c>Q_i</c> is a qualifier, then Rep(E) = + <c>{lc,LINE,Rep(E_0),[Rep(Q_1), ..., Rep(Q_k)]}</c>. + For Rep(Q), see below.</p> + </item> + <item> + <p>If E is a map creation <c>#{A_1, ..., A_k}</c>, + where each <c>A_i</c> is an association <c>E_i_1 => E_i_2</c> + or <c>E_i_1 := E_i_2</c>, then Rep(E) = + <c>{map,LINE,[Rep(A_1), ..., Rep(A_k)]}</c>. + For Rep(A), see below.</p> + </item> + <item> + <p>If E is a map update <c>E_0#{A_1, ..., A_k}</c>, + where each <c>A_i</c> is an association <c>E_i_1 => E_i_2</c> + or <c>E_i_1 := E_i_2</c>, then Rep(E) = + <c>{map,LINE,Rep(E_0),[Rep(A_1), ..., Rep(A_k)]}</c>. + For Rep(A), see below.</p> + </item> + <item> + <p>If E is a match operator expression <c>P = E_0</c>, + where <c>P</c> is a pattern, then Rep(E) = + <c>{match,LINE,Rep(P),Rep(E_0)}</c>.</p> + </item> + <item> + <p>If E is nil, <c>[]</c>, then Rep(E) = <c>{nil,LINE}</c>.</p> + </item> + <item> + <p>If E is an operator expression <c>E_1 Op E_2</c>, + where <c>Op</c> is a binary operator other than match operator + <c>=</c>, then Rep(E) = + <c>{op,LINE,Op,Rep(E_1),Rep(E_2)}</c>.</p> + </item> + <item> + <p>If E is an operator expression <c>Op E_0</c>, + where <c>Op</c> is a unary operator, then Rep(E) = + <c>{op,LINE,Op,Rep(E_0)}</c>.</p> + </item> + <item> + <p>If E is a parenthesized expression <c>( E_0 )</c>, then Rep(E) = + <c>Rep(E_0)</c>, that is, parenthesized expressions cannot be + distinguished from their bodies.</p> + </item> + <item> + <p>If E is a receive expression <c>receive Cc_1 ; ... ; Cc_k end</c>, + where each <c>Cc_i</c> is a case clause, then Rep(E) = + <c>{'receive',LINE,[Rep(Cc_1), ..., Rep(Cc_k)]}</c>.</p> + </item> + <item> + <p>If E is a receive expression + <c>receive Cc_1 ; ... ; Cc_k after E_0 -> B_t end</c>, + where each <c>Cc_i</c> is a case clause, <c>E_0</c> is an expression, + and <c>B_t</c> is a body, then Rep(E) = + <c>{'receive',LINE,[Rep(Cc_1), ..., + Rep(Cc_k)],Rep(E_0),Rep(B_t)}</c>.</p> + </item> + <item> + <p>If E is a record creation + <c>#Name{Field_1=E_1, ..., Field_k=E_k}</c>, + where each <c>Field_i</c> is an atom or <c>_</c>, then Rep(E) = + <c>{record,LINE,Name,[{record_field,LINE,Rep(Field_1),Rep(E_1)}, + ..., {record_field,LINE,Rep(Field_k),Rep(E_k)}]}</c>.</p> + </item> + <item> + <p>If E is a record field access <c>E_0#Name.Field</c>, + where <c>Field</c> is an atom, then Rep(E) = + <c>{record_field,LINE,Rep(E_0),Name,Rep(Field)}</c>.</p> + </item> + <item> + <p>If E is a record field index <c>#Name.Field</c>, + where <c>Field</c> is an atom, then Rep(E) = + <c>{record_index,LINE,Name,Rep(Field)}</c>.</p></item> + <item> + <p>If E is a record update + <c>E_0#Name{Field_1=E_1, ..., Field_k=E_k}</c>, + where each <c>Field_i</c> is an atom, then Rep(E) = + <c>{record,LINE,Rep(E_0),Name,[{record_field,LINE,Rep(Field_1),Rep(E_1)}, + ..., {record_field,LINE,Rep(Field_k),Rep(E_k)}]}</c>.</p> + </item> + <item> + <p>If E is a tuple skeleton <c>{E_1, ..., E_k}</c>, then Rep(E) = + <c>{tuple,LINE,[Rep(E_1), ..., Rep(E_k)]}</c>.</p> + </item> + <item> + <p>If E is a try expression <c>try B catch Tc_1 ; ... ; Tc_k end</c>, + where <c>B</c> is a body and each <c>Tc_i</c> is a catch clause, + then Rep(E) = + <c>{'try',LINE,Rep(B),[],[Rep(Tc_1), ..., Rep(Tc_k)],[]}</c>.</p> + </item> + <item> + <p>If E is a try expression + <c>try B of Cc_1 ; ... ; Cc_k catch Tc_1 ; ... ; Tc_n end</c>, + where <c>B</c> is a body, each <c>Cc_i</c> is a case clause, and + each <c>Tc_j</c> is a catch clause, then Rep(E) = + <c>{'try',LINE,Rep(B),[Rep(Cc_1), ..., Rep(Cc_k)],[Rep(Tc_1), ..., + Rep(Tc_n)],[]}</c>.</p> + </item> + <item> + <p>If E is a try expression <c>try B after A end</c>, + where <c>B</c> and <c>A</c> are bodies, then Rep(E) = + <c>{'try',LINE,Rep(B),[],[],Rep(A)}</c>.</p> + </item> + <item> + <p>If E is a try expression + <c>try B of Cc_1 ; ... ; Cc_k after A end</c>, + where <c>B</c> and <c>A</c> are a bodies, + and each <c>Cc_i</c> is a case clause, then Rep(E) = + <c>{'try',LINE,Rep(B),[Rep(Cc_1), ..., + Rep(Cc_k)],[],Rep(A)}</c>.</p> + </item> + <item> + <p>If E is a try expression + <c>try B catch Tc_1 ; ... ; Tc_k after A end</c>, + where <c>B</c> and <c>A</c> are bodies, + and each <c>Tc_i</c> is a catch clause, then Rep(E) = + <c>{'try',LINE,Rep(B),[],[Rep(Tc_1), ..., + Rep(Tc_k)],Rep(A)}</c>.</p> + </item> + <item> + <p>If E is a try expression + <c>try B of Cc_1 ; ... ; Cc_k catch Tc_1 ; ... ; Tc_n after A + end</c>, where <c>B</c> and <c>A</c> are a bodies, + each <c>Cc_i</c> is a case clause, + and each <c>Tc_j</c> is a catch clause, then Rep(E) = + <c>{'try',LINE,Rep(B),[Rep(Cc_1), ..., Rep(Cc_k)],[Rep(Tc_1), ..., + Rep(Tc_n)],Rep(A)}</c>.</p> + </item> + <item> + <p>If E is a variable <c>V</c>, then Rep(E) = <c>{var,LINE,A}</c>, + where <c>A</c> is an atom with a printname consisting of the same + characters as <c>V</c>.</p> + </item> </list> <section> - <title>Generators and filters</title> - <p>When W is a generator or a filter (in the body of a list or binary comprehension), then:</p> + <title>Qualifiers</title> + <p>A qualifier Q is one of the following:</p> + <list type="bulleted"> - <item>If W is a generator <c><![CDATA[P <- E]]></c>, where <c><![CDATA[P]]></c> is a pattern and <c><![CDATA[E]]></c> - is an expression, then - Rep(W) = <c><![CDATA[{generate,LINE,Rep(P),Rep(E)}]]></c>.</item> - <item>If W is a generator <c><![CDATA[P <= E]]></c>, where <c><![CDATA[P]]></c> is a pattern and <c><![CDATA[E]]></c> - is an expression, then - Rep(W) = <c><![CDATA[{b_generate,LINE,Rep(P),Rep(E)}]]></c>.</item> - <item>If W is a filter <c><![CDATA[E]]></c>, which is an expression, then - Rep(W) = <c><![CDATA[Rep(E)]]></c>.</item> + <item> + <p>If Q is a filter <c>E</c>, where <c>E</c> is an expression, then + Rep(Q) = <c>Rep(E)</c>.</p> + </item> + <item> + <p>If Q is a generator <c>P <- E</c>, where <c>P</c> is + a pattern and <c>E</c> is an expression, then Rep(Q) = + <c>{generate,LINE,Rep(P),Rep(E)}</c>.</p> + </item> + <item> + <p>If Q is a bitstring generator <c>P <= E</c>, where <c>P</c> is + a pattern and <c>E</c> is an expression, then Rep(Q) = + <c>{b_generate,LINE,Rep(P),Rep(E)}</c>.</p> + </item> </list> </section> <section> - <title>Binary element type specifiers</title> - <p>A type specifier list TSL for a binary element is a sequence of type - specifiers <c><![CDATA[TS_1 - ... - TS_k]]></c>. - Rep(TSL) = <c><![CDATA[[Rep(TS_1), ..., Rep(TS_k)]]]></c>.</p> - <p>When TS is a type specifier for a binary element, then:</p> + <title>Bitstring Element Type Specifiers</title> + <p>A type specifier list TSL for a bitstring element is a sequence + of type specifiers <c>TS_1 - ... - TS_k</c>, and + Rep(TSL) = <c>[Rep(TS_1), ..., Rep(TS_k)]</c>.</p> + <list type="bulleted"> - <item>If TS is an atom <c><![CDATA[A]]></c>, Rep(TS) = <c><![CDATA[A]]></c>.</item> - <item>If TS is a couple <c><![CDATA[A:Value]]></c> where <c><![CDATA[A]]></c> is an atom and <c><![CDATA[Value]]></c> - is an integer, Rep(TS) = <c><![CDATA[{A, Value}]]></c>.</item> + <item> + <p>If TS is a type specifier <c>A</c>, where <c>A</c> is an atom, + then Rep(TS) = <c>A</c>.</p> + </item> + <item> + <p>If TS is a type specifier <c>A:Value</c>, + where <c>A</c> is an atom and <c>Value</c> is an integer, + then Rep(TS) = <c>{A,Value}</c>.</p> + </item> </list> </section> <section> - <title>Map assoc and exact fields</title> - <p>When W is an assoc or exact field (in the body of a map), then:</p> + <title>Associations</title> + <p>An association A is one of the following:</p> + <list type="bulleted"> - <item>If W is an assoc field <c><![CDATA[K => V]]></c>, where - <c><![CDATA[K]]></c> and <c><![CDATA[V]]></c> are both expressions, - then Rep(W) = <c><![CDATA[{map_field_assoc,LINE,Rep(K),Rep(V)}]]></c>. - </item> - <item>If W is an exact field <c><![CDATA[K := V]]></c>, where - <c><![CDATA[K]]></c> and <c><![CDATA[V]]></c> are both expressions, - then Rep(W) = <c><![CDATA[{map_field_exact,LINE,Rep(K),Rep(V)}]]></c>. - </item> + <item> + <p>If A is an association <c>K => V</c>, + then Rep(A) = <c>{map_field_assoc,LINE,Rep(K),Rep(V)}</c>.</p> + </item> + <item> + <p>If A is an association <c>K := V</c>, + then Rep(A) = <c>{map_field_exact,LINE,Rep(K),Rep(V)}</c>.</p> + </item> </list> </section> </section> <section> <title>Clauses</title> - <p>There are function clauses, if clauses, case clauses + <p>There are function clauses, if clauses, case clauses, and catch clauses.</p> - <p>A clause <c><![CDATA[C]]></c> is one of the following alternatives:</p> + + <p>A clause C is one of the following:</p> + <list type="bulleted"> - <item>If C is a function clause <c><![CDATA[( Ps ) -> B]]></c> - where <c><![CDATA[Ps]]></c> is a pattern sequence and <c><![CDATA[B]]></c> is a body, then - Rep(C) = <c><![CDATA[{clause,LINE,Rep(Ps),[],Rep(B)}]]></c>.</item> - <item>If C is a function clause <c><![CDATA[( Ps ) when Gs -> B]]></c> - where <c><![CDATA[Ps]]></c> is a pattern sequence, - <c><![CDATA[Gs]]></c> is a guard sequence and <c><![CDATA[B]]></c> is a body, then - Rep(C) = <c><![CDATA[{clause,LINE,Rep(Ps),Rep(Gs),Rep(B)}]]></c>.</item> - <item>If C is an if clause <c><![CDATA[Gs -> B]]></c> - where <c><![CDATA[Gs]]></c> is a guard sequence and <c><![CDATA[B]]></c> is a body, then - Rep(C) = <c><![CDATA[{clause,LINE,[],Rep(Gs),Rep(B)}]]></c>.</item> - <item>If C is a case clause <c><![CDATA[P -> B]]></c> - where <c><![CDATA[P]]></c> is a pattern and <c><![CDATA[B]]></c> is a body, then - Rep(C) = <c><![CDATA[{clause,LINE,[Rep(P)],[],Rep(B)}]]></c>.</item> - <item>If C is a case clause <c><![CDATA[P when Gs -> B]]></c> - where <c><![CDATA[P]]></c> is a pattern, - <c><![CDATA[Gs]]></c> is a guard sequence and <c><![CDATA[B]]></c> is a body, then - Rep(C) = <c><![CDATA[{clause,LINE,[Rep(P)],Rep(Gs),Rep(B)}]]></c>.</item> - <item>If C is a catch clause <c><![CDATA[P -> B]]></c> - where <c><![CDATA[P]]></c> is a pattern and <c><![CDATA[B]]></c> is a body, then - Rep(C) = <c><![CDATA[{clause,LINE,[Rep({throw,P,_})],[],Rep(B)}]]></c>.</item> - <item>If C is a catch clause <c><![CDATA[X : P -> B]]></c> - where <c><![CDATA[X]]></c> is an atomic literal or a variable pattern, - <c><![CDATA[P]]></c> is a pattern and <c><![CDATA[B]]></c> is a body, then - Rep(C) = <c><![CDATA[{clause,LINE,[Rep({X,P,_})],[],Rep(B)}]]></c>.</item> - <item>If C is a catch clause <c><![CDATA[P when Gs -> B]]></c> - where <c><![CDATA[P]]></c> is a pattern, <c><![CDATA[Gs]]></c> is a guard sequence - and <c><![CDATA[B]]></c> is a body, then - Rep(C) = <c><![CDATA[{clause,LINE,[Rep({throw,P,_})],Rep(Gs),Rep(B)}]]></c>.</item> - <item>If C is a catch clause <c><![CDATA[X : P when Gs -> B]]></c> - where <c><![CDATA[X]]></c> is an atomic literal or a variable pattern, - <c><![CDATA[P]]></c> is a pattern, <c><![CDATA[Gs]]></c> is a guard sequence - and <c><![CDATA[B]]></c> is a body, then - Rep(C) = <c><![CDATA[{clause,LINE,[Rep({X,P,_})],Rep(Gs),Rep(B)}]]></c>.</item> + <item> + <p>If C is a case clause <c>P -> B</c>, + where <c>P</c> is a pattern and <c>B</c> is a body, then + Rep(C) = <c>{clause,LINE,[Rep(P)],[],Rep(B)}</c>.</p> + </item> + <item> + <p>If C is a case clause <c>P when Gs -> B</c>, + where <c>P</c> is a pattern, + <c>Gs</c> is a guard sequence, and <c>B</c> is a body, then + Rep(C) = <c>{clause,LINE,[Rep(P)],Rep(Gs),Rep(B)}</c>.</p> + </item> + <item> + <p>If C is a catch clause <c>P -> B</c>, + where <c>P</c> is a pattern and <c>B</c> is a body, then + Rep(C) = <c>{clause,LINE,[Rep({throw,P,_})],[],Rep(B)}</c>.</p> + </item> + <item> + <p>If C is a catch clause <c>X : P -> B</c>, + where <c>X</c> is an atomic literal or a variable pattern, + <c>P</c> is a pattern, and <c>B</c> is a body, then + Rep(C) = <c>{clause,LINE,[Rep({X,P,_})],[],Rep(B)}</c>.</p> + </item> + <item> + <p>If C is a catch clause <c>P when Gs -> B</c>, + where <c>P</c> is a pattern, <c>Gs</c> is a guard sequence, + and <c>B</c> is a body, then + Rep(C) = <c>{clause,LINE,[Rep({throw,P,_})],Rep(Gs),Rep(B)}</c>.</p> + </item> + <item> + <p>If C is a catch clause <c>X : P when Gs -> B</c>, + where <c>X</c> is an atomic literal or a variable pattern, + <c>P</c> is a pattern, <c>Gs</c> is a guard sequence, + and <c>B</c> is a body, then + Rep(C) = <c>{clause,LINE,[Rep({X,P,_})],Rep(Gs),Rep(B)}</c>.</p> + </item> + <item> + <p>If C is a function clause <c>( Ps ) -> B</c>, + where <c>Ps</c> is a pattern sequence and <c>B</c> is a body, then + Rep(C) = <c>{clause,LINE,Rep(Ps),[],Rep(B)}</c>.</p> + </item> + <item> + <p>If C is a function clause <c>( Ps ) when Gs -> B</c>, + where <c>Ps</c> is a pattern sequence, + <c>Gs</c> is a guard sequence and <c>B</c> is a body, then + Rep(C) = <c>{clause,LINE,Rep(Ps),Rep(Gs),Rep(B)}</c>.</p> + </item> + <item> + <p>If C is an if clause <c>Gs -> B</c>, + where <c>Gs</c> is a guard sequence and <c>B</c> is a body, then + Rep(C) = <c>{clause,LINE,[],Rep(Gs),Rep(B)}</c>.</p> + </item> </list> </section> <section> <title>Guards</title> - <p>A guard sequence Gs is a sequence of guards <c><![CDATA[G_1; ...; G_k]]></c>, and - Rep(Gs) = <c><![CDATA[[Rep(G_1), ..., Rep(G_k)]]]></c>. If the guard sequence is - empty, Rep(Gs) = <c><![CDATA[[]]]></c>.</p> - <p>A guard G is a nonempty sequence of guard tests <c><![CDATA[Gt_1, ..., Gt_k]]></c>, and - Rep(G) = <c><![CDATA[[Rep(Gt_1), ..., Rep(Gt_k)]]]></c>.</p> - <p>A guard test <c><![CDATA[Gt]]></c> is one of the following alternatives:</p> + <p>A guard sequence Gs is a sequence of guards <c>G_1; ...; G_k</c>, and + Rep(Gs) = <c>[Rep(G_1), ..., Rep(G_k)]</c>. If the guard sequence is + empty, then Rep(Gs) = <c>[]</c>.</p> + + <p>A guard G is a non-empty sequence of guard tests + <c>Gt_1, ..., Gt_k</c>, and Rep(G) = + <c>[Rep(Gt_1), ..., Rep(Gt_k)]</c>.</p> + + <p>A guard test Gt is one of the following:</p> + <list type="bulleted"> - <item>If Gt is an atomic literal L, then Rep(Gt) = Rep(L).</item> - <item>If Gt is a variable pattern <c><![CDATA[V]]></c>, then - Rep(Gt) = <c><![CDATA[{var,LINE,A}]]></c>, - where A is an atom with a printname consisting of the same characters as - <c><![CDATA[V]]></c>.</item> - <item>If Gt is a tuple skeleton <c><![CDATA[{Gt_1, ..., Gt_k}]]></c>, then - Rep(Gt) = <c><![CDATA[{tuple,LINE,[Rep(Gt_1), ..., Rep(Gt_k)]}]]></c>.</item> - <item>If Gt is <c><![CDATA[[]]]></c>, then - Rep(Gt) = <c><![CDATA[{nil,LINE}]]></c>.</item> - <item>If Gt is a cons skeleton <c><![CDATA[[Gt_h | Gt_t]]]></c>, then - Rep(Gt) = <c><![CDATA[{cons,LINE,Rep(Gt_h),Rep(Gt_t)}]]></c>.</item> - <item>If Gt is a binary constructor <c><![CDATA[<<Gt_1:Size_1/TSL_1, ..., Gt_k:Size_k/TSL_k>>]]></c>, then - Rep(Gt) = <c><![CDATA[{bin,LINE,[{bin_element,LINE,Rep(Gt_1),Rep(Size_1),Rep(TSL_1)}, ..., {bin_element,LINE,Rep(Gt_k),Rep(Size_k),Rep(TSL_k)}]}]]></c>. - For Rep(TSL), see above. - An omitted <c><![CDATA[Size]]></c> is represented by <c><![CDATA[default]]></c>. An omitted <c><![CDATA[TSL]]></c> - (type specifier list) is represented by <c><![CDATA[default]]></c>.</item> - <item>If Gt is <c><![CDATA[Gt_1 Op Gt_2]]></c>, where <c><![CDATA[Op]]></c> - is a binary operator, then Rep(Gt) = <c><![CDATA[{op,LINE,Op,Rep(Gt_1),Rep(Gt_2)}]]></c>.</item> - <item>If Gt is <c><![CDATA[Op Gt_0]]></c>, where <c><![CDATA[Op]]></c> is a unary operator, then - Rep(Gt) = <c><![CDATA[{op,LINE,Op,Rep(Gt_0)}]]></c>.</item> - <item>If Gt is <c><![CDATA[#Name{Field_1=Gt_1, ..., Field_k=Gt_k}]]></c>, then - Rep(E) = - <c><![CDATA[{record,LINE,Name, [{record_field,LINE,Rep(Field_1),Rep(Gt_1)}, ..., {record_field,LINE,Rep(Field_k),Rep(Gt_k)}]}]]></c>.</item> - <item>If Gt is <c><![CDATA[#Name.Field]]></c>, then - Rep(Gt) = <c><![CDATA[{record_index,LINE,Name,Rep(Field)}]]></c>.</item> - <item>If Gt is <c><![CDATA[Gt_0#Name.Field]]></c>, then - Rep(Gt) = <c><![CDATA[{record_field,LINE,Rep(Gt_0),Name,Rep(Field)}]]></c>.</item> - <item>If Gt is <c><![CDATA[A(Gt_1, ..., Gt_k)]]></c>, where <c><![CDATA[A]]></c> is an atom, then - Rep(Gt) = <c><![CDATA[{call,LINE,Rep(A),[Rep(Gt_1), ..., Rep(Gt_k)]}]]></c>.</item> - <item>If Gt is <c><![CDATA[A_m:A(Gt_1, ..., Gt_k)]]></c>, where <c><![CDATA[A_m]]></c> is - the atom <c><![CDATA[erlang]]></c> and <c><![CDATA[A]]></c> is an atom or an operator, then - Rep(Gt) = <c><![CDATA[{call,LINE,{remote,LINE,Rep(A_m),Rep(A)},[Rep(Gt_1), ..., Rep(Gt_k)]}]]></c>.</item> - <item>If Gt is <c><![CDATA[{A_m,A}(Gt_1, ..., Gt_k)]]></c>, where <c><![CDATA[A_m]]></c> is - the atom <c><![CDATA[erlang]]></c> and <c><![CDATA[A]]></c> is an atom or an operator, then - Rep(Gt) = <c><![CDATA[{call,LINE,Rep({A_m,A}),[Rep(Gt_1), ..., Rep(Gt_k)]}]]></c>.</item> - <item>If Gt is <c><![CDATA[( Gt_0 )]]></c>, then - Rep(Gt) = <c><![CDATA[Rep(Gt_0)]]></c>, - i.e., parenthesized guard tests cannot be distinguished from their bodies.</item> + <item> + <p>If Gt is an atomic literal <c>L</c>, then Rep(Gt) = Rep(L).</p> + </item> + <item> + <p>If Gt is a bitstring constructor + <c><<Gt_1:Size_1/TSL_1, ..., Gt_k:Size_k/TSL_k>></c>, + where each <c>Size_i</c> is a guard test and each + <c>TSL_i</c> is a type specificer list, then Rep(Gt) = + <c>{bin,LINE,[{bin_element,LINE,Rep(Gt_1),Rep(Size_1),Rep(TSL_1)}, + ..., {bin_element,LINE,Rep(Gt_k),Rep(Size_k),Rep(TSL_k)}]}</c>. + For Rep(TSL), see above. + An omitted <c>Size_i</c> is represented by <c>default</c>. + An omitted <c>TSL_i</c> is represented by <c>default</c>.</p> + </item> + <item> + <p>If Gt is a cons skeleton <c>[Gt_h | Gt_t]</c>, then Rep(Gt) = + <c>{cons,LINE,Rep(Gt_h),Rep(Gt_t)}</c>.</p> + </item> + <item> + <p>If Gt is a function call <c>A(Gt_1, ..., Gt_k)</c>, + where <c>A</c> is an atom, then Rep(Gt) = + <c>{call,LINE,Rep(A),[Rep(Gt_1), ..., Rep(Gt_k)]}</c>.</p> + </item> + <item> + <p>If Gt is a function call <c>A_m:A(Gt_1, ..., Gt_k)</c>, + where <c>A_m</c> is the atom <c>erlang</c> and <c>A</c> is + an atom or an operator, then Rep(Gt) = + <c>{call,LINE,{remote,LINE,Rep(A_m),Rep(A)},[Rep(Gt_1), ..., + Rep(Gt_k)]}</c>.</p> + </item> + <item> + <p>If Gt is a map creation <c>#{A_1, ..., A_k}</c>, + where each <c>A_i</c> is an association <c>Gt_i_1 => Gt_i_2</c> + or <c>Gt_i_1 := Gt_i_2</c>, then Rep(Gt) = + <c>{map,LINE,[Rep(A_1), ..., Rep(A_k)]}</c>. + For Rep(A), see above.</p> + </item> + <item> + <p>If Gt is a map update <c>Gt_0#{A_1, ..., A_k}</c>, + where each <c>A_i</c> is an association <c>Gt_i_1 => Gt_i_2</c> + or <c>Gt_i_1 := Gt_i_2</c>, then Rep(Gt) = + <c>{map,LINE,Rep(Gt_0),[Rep(A_1), ..., Rep(A_k)]}</c>. + For Rep(A), see above.</p> + </item> + <item> + <p>If Gt is nil, <c>[]</c>, then Rep(Gt) = <c>{nil,LINE}</c>.</p> + </item> + <item> + <p>If Gt is an operator guard test <c>Gt_1 Op Gt_2</c>, + where <c>Op</c> is a binary operator other than match + operator <c>=</c>, then Rep(Gt) = + <c>{op,LINE,Op,Rep(Gt_1),Rep(Gt_2)}</c>.</p> + </item> + <item> + <p>If Gt is an operator guard test <c>Op Gt_0</c>, + where <c>Op</c> is a unary operator, then Rep(Gt) = + <c>{op,LINE,Op,Rep(Gt_0)}</c>.</p> + </item> + <item> + <p>If Gt is a parenthesized guard test <c>( Gt_0 )</c>, then Rep(Gt) = + <c>Rep(Gt_0)</c>, that is, parenthesized + guard tests cannot be distinguished from their bodies.</p> + </item> + <item> + <p>If Gt is a record creation + <c>#Name{Field_1=Gt_1, ..., Field_k=Gt_k}</c>, + where each <c>Field_i</c> is an atom or <c>_</c>, then Rep(Gt) = + <c>{record,LINE,Name,[{record_field,LINE,Rep(Field_1),Rep(Gt_1)}, + ..., {record_field,LINE,Rep(Field_k),Rep(Gt_k)}]}</c>.</p> + </item> + <item> + <p>If Gt is a record field access <c>Gt_0#Name.Field</c>, + where <c>Field</c> is an atom, then Rep(Gt) = + <c>{record_field,LINE,Rep(Gt_0),Name,Rep(Field)}</c>.</p> + </item> + <item> + <p>If Gt is a record field index <c>#Name.Field</c>, + where <c>Field</c> is an atom, then Rep(Gt) = + <c>{record_index,LINE,Name,Rep(Field)}</c>.</p> + </item> + <item> + <p>If Gt is a tuple skeleton <c>{Gt_1, ..., Gt_k}</c>, then Rep(Gt) = + <c>{tuple,LINE,[Rep(Gt_1), ..., Rep(Gt_k)]}</c>.</p> + </item> + <item> + <p>If Gt is a variable pattern <c>V</c>, then Rep(Gt) = + <c>{var,LINE,A}</c>, where A is an atom with + a printname consisting of the same characters as <c>V</c>.</p> + </item> </list> - <p>Note that every guard test has the same source form as some expression, - and is represented the same way as the corresponding expression.</p> + + <p>Notice that every guard test has the same source form as some expression, + and is represented in the same way as the corresponding expression.</p> + </section> + + <section> + <title>Types</title> + <list type="bulleted"> + <item> + <p>If T is an annotated type <c>A :: T_0</c>, + where <c>A</c> is a variable, then Rep(T) = + <c>{ann_type,LINE,[Rep(A),Rep(T_0)]}</c>.</p> + </item> + <item> + <p>If T is an atom or integer literal L, then Rep(T) = Rep(L).</p> + </item> + <item> + <p>If T is a bitstring type <c><<_:M,_:_*N>></c>, + where <c>M</c> and <c>N</c> are singleton integer types, then Rep(T) = + <c>{type,LINE,binary,[Rep(M),Rep(N)]}</c>.</p> + </item> + <item> + <p>If T is the empty list type <c>[]</c>, then Rep(T) = + <c>{type,Line,nil,[]}</c>.</p> + </item> + <item> + <p>If T is a fun type <c>fun()</c>, then Rep(T) = + <c>{type,LINE,'fun',[]}</c>.</p> + </item> + <item> + <p>If T is a fun type <c>fun((...) -> T_0)</c>, then Rep(T) = + <c>{type,LINE,'fun',[{type,LINE,any},Rep(T_0)]}</c>.</p> + </item> + <item> + <p>If T is a fun type <c>fun(Ft)</c>, where + <c>Ft</c> is a function type, then Rep(T) = <c>Rep(Ft)</c>. + For Rep(Ft), see below.</p> + </item> + <item> + <p>If T is an integer range type <c>L .. H</c>, + where <c>L</c> and <c>H</c> are singleton integer types, then Rep(T) = + <c>{type,LINE,range,[Rep(L),Rep(H)]}</c>.</p> + </item> + <item> + <p>If T is a map type <c>map()</c>, then Rep(T) = + <c>{type,LINE,map,any}</c>.</p> + </item> + <item> + <p>If T is a map type <c>#{A_1, ..., A_k}</c>, where each + <c>A_i</c> is an association type, then Rep(T) = + <c>{type,LINE,map,[Rep(A_1), ..., Rep(A_k)]}</c>. + For Rep(A), see below.</p> + </item> + <item> + <p>If T is an operator type <c>T_1 Op T_2</c>, + where <c>Op</c> is a binary operator (this is an occurrence of + an expression that can be evaluated to an integer at compile + time), then Rep(T) = + <c>{op,LINE,Op,Rep(T_1),Rep(T_2)}</c>.</p> + </item> + <item> + <p>If T is an operator type <c>Op T_0</c>, where <c>Op</c> is a + unary operator (this is an occurrence of an expression that can + be evaluated to an integer at compile time), then Rep(T) = + <c>{op,LINE,Op,Rep(T_0)}</c>.</p> + </item> + <item> + <p>If T is <c>( T_0 )</c>, then Rep(T) = <c>Rep(T_0)</c>, that is, + parenthesized types cannot be distinguished from their bodies.</p> + </item> + <item> + <p>If T is a predefined (or built-in) type <c>N(T_1, ..., T_k)</c>, + then Rep(T) = <c>{type,LINE,N,[Rep(T_1), ..., Rep(T_k)]}</c>.</p> + </item> + <item> + <p>If T is a record type <c>#Name{F_1, ..., F_k}</c>, + where each <c>F_i</c> is a record field type, then Rep(T) = + <c>{type,LINE,record,[Rep(Name),Rep(F_1), ..., Rep(F_k)]}</c>. + For Rep(F), see below.</p> + </item> + <item> + <p>If T is a remote type <c>M:N(T_1, ..., T_k)</c>, then Rep(T) = + <c>{remote_type,LINE,[Rep(M),Rep(N),[Rep(T_1), ..., + Rep(T_k)]]}</c>.</p> + </item> + <item> + <p>If T is a tuple type <c>tuple()</c>, then Rep(T) = + <c>{type,LINE,tuple,any}</c>.</p> + </item> + <item> + <p>If T is a tuple type <c>{T_1, ..., T_k}</c>, then Rep(T) = + <c>{type,LINE,tuple,[Rep(T_1), ..., Rep(T_k)]}</c>.</p> + </item> + <item> + <p>If T is a type union <c>T_1 | ... | T_k</c>, then Rep(T) = + <c>{type,LINE,union,[Rep(T_1), ..., Rep(T_k)]}</c>.</p> + </item> + <item> + <p>If T is a type variable <c>V</c>, then Rep(T) = + <c>{var,LINE,A}</c>, where <c>A</c> is an atom with a printname + consisting of the same characters as <c>V</c>. A type variable + is any variable except underscore (<c>_</c>).</p> + </item> + <item> + <p>If T is a user-defined type <c>N(T_1, ..., T_k)</c>, then Rep(T) = + <c>{user_type,LINE,N,[Rep(T_1), ..., Rep(T_k)]}</c>.</p> + </item> + </list> + + <section> + <title>Function Types</title> + <p>A function type Ft is one of the following:</p> + + <list type="bulleted"> + <item> + <p>If Ft is a constrained function type <c>Ft_1 when Fc</c>, + where <c>Ft_1</c> is a function type and + <c>Fc</c> is a function constraint, then Rep(T) = + <c>{type,LINE,bounded_fun,[Rep(Ft_1),Rep(Fc)]}</c>. + For Rep(Fc), see below.</p> + </item> + <item> + <p>If Ft is a function type <c>(T_1, ..., T_n) -> T_0</c>, + where each <c>T_i</c> is a type, then Rep(Ft) = + <c>{type,LINE,'fun',[{type,LINE,product,[Rep(T_1), ..., + Rep(T_n)]},Rep(T_0)]}</c>.</p> + </item> + </list> + </section> + + <section> + <title>Function Constraints</title> + <p>A function constraint Fc is a non-empty sequence of constraints + <c>C_1, ..., C_k</c>, and + Rep(Fc) = <c>[Rep(C_1), ..., Rep(C_k)]</c>.</p> + + <list type="bulleted"> + <item>If C is a constraint <c>V :: T</c>, + where <c>V</c> is a type variable + and <c>T</c> is a type, then Rep(C) = + <c>{type,LINE,constraint,[{atom,LINE,is_subtype},[Rep(V),Rep(T)]]}</c>. + </item> + </list> + </section> + + <section> + <title>Association Types</title> + <list type="bulleted"> + <item> + <p>If A is an association type <c>K => V</c>, + where <c>K</c> and <c>V</c> are types, then Rep(A) = + <c>{type,LINE,map_field_assoc,[Rep(K),Rep(V)]}</c>.</p> + </item> + <item> + <p>If A is an association type <c>K := V</c>, + where <c>K</c> and <c>V</c> are types, then Rep(A) = + <c>{type,LINE,map_field_exact,[Rep(K),Rep(V)]}</c>.</p> + </item> + </list> + </section> + + <section> + <title>Record Field Types</title> + <list type="bulleted"> + <item>If F is a record field type <c>Name :: Type</c>, + where <c>Type</c> is a type, then Rep(F) = + <c>{type,LINE,field_type,[Rep(Name),Rep(Type)]}</c>. + </item> + </list> + </section> </section> <section> - <title>The abstract format after preprocessing</title> - <p>The compilation option <c><![CDATA[debug_info]]></c> can be given to the - compiler to have the abstract code stored in - the <c><![CDATA[abstract_code]]></c> chunk in the BEAM file + <title>The Abstract Format after Preprocessing</title> + <p>The compilation option <c>debug_info</c> can be specified to the + compiler to have the abstract code stored in + the <c>abstract_code</c> chunk in the Beam file (for debugging purposes).</p> - <p>In OTP R9C and later, the <c><![CDATA[abstract_code]]></c> chunk will - contain</p> - <p><c><![CDATA[{raw_abstract_v1,AbstractCode}]]></c></p> - <p>where <c><![CDATA[AbstractCode]]></c> is the abstract code as described - in this document.</p> - <p>In releases of OTP prior to R9C, the abstract code after some more - processing was stored in the BEAM file. The first element of the - tuple would be either <c><![CDATA[abstract_v1]]></c> (R7B) or <c><![CDATA[abstract_v2]]></c> - (R8B).</p> + + <p>As from Erlang/OTP R9C, the <c>abstract_code</c> chunk contains + <c>{raw_abstract_v1,AbstractCode}</c>, where <c>AbstractCode</c> is the + abstract code as described in this section.</p> + + <p>In OTP releases before R9C, the abstract code after some more + processing was stored in the Beam file. The first element of the + tuple would be either <c>abstract_v1</c> (in OTP R7B) or + <c>abstract_v2</c> (in OTP R8B).</p> </section> </chapter> |