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#############################################################################
##
#W record.g GAP library Thomas Breuer
#W & Frank Celler
##
#H @(#)$Id: record.g,v 4.17.2.1 2005/04/27 16:31:22 gap Exp $
##
#Y Copyright (C) 1997, Lehrstuhl D fuer Mathematik, RWTH Aachen, Germany
#Y (C) 1998 School Math and Comp. Sci., University of St. Andrews, Scotland
#Y Copyright (C) 2002 The GAP Group
##
## This file contains methods for records.
## Compared to {\GAP}~3, where records were used to represent domains and
## all kinds of external arithmetic objects, in {\GAP}~4 there is no
## important role for records.
## So the standard library provides only methods for `PrintObj', `String',
## `\=', and `\<', and the latter two are not installed to compare records
## with objects in other families.
##
## In order to achieve a special behaviour of records as in {\GAP}~3 such
## that a record can be regarded as equal to objects in other families
## or such that a record can be compared via `\<' with objects in other
## families, one can load the file `compat3c.g'.
##
Revision.record_g :=
"@(#)$Id: record.g,v 4.17.2.1 2005/04/27 16:31:22 gap Exp $";
#############################################################################
##
#C IsRecord( <obj> )
#C IsRecordCollection( <obj> )
#C IsRecordCollColl( <obj> )
##
DeclareCategoryKernel( "IsRecord", IsObject, IS_REC );
DeclareCategoryCollections( "IsRecord" );
DeclareCategoryCollections( "IsRecordCollection" );
#############################################################################
##
#V RecordsFamily . . . . . . . . . . . . . . . . . . . . . family of records
##
BIND_GLOBAL( "RecordsFamily", NewFamily( "RecordsFamily", IS_REC ) );
#############################################################################
##
#V TYPE_PREC_MUTABLE . . . . . . . . . . . type of a mutable internal record
##
BIND_GLOBAL( "TYPE_PREC_MUTABLE",
NewType( RecordsFamily, IS_MUTABLE_OBJ and IS_REC and IsInternalRep ) );
#############################################################################
##
#V TYPE_PREC_IMMUTABLE . . . . . . . . type of an immutable internal record
##
BIND_GLOBAL( "TYPE_PREC_IMMUTABLE",
NewType( RecordsFamily, IS_REC and IsInternalRep ) );
#############################################################################
##
#o \.( <rec>, <name> ) . . . . . . . . . . . . . . . . get a component value
##
DeclareOperationKernel( ".", [ IsObject, IsObject ], ELM_REC );
#############################################################################
##
#o IsBound\.( <rec>, <name> ) . . . . . . . . . . . . . . test a component
##
DeclareOperationKernel( "IsBound.", [ IsObject, IsObject ], ISB_REC );
#############################################################################
##
#o \.\:\=( <rec>, <name>, <val> ) . . . . . . . . . . . . . assign a value
##
DeclareOperationKernel( ".:=", [ IsObject, IsObject, IsObject ], ASS_REC );
#############################################################################
##
#o Unbind\.( <rec>, <name> ) . . . . . . . . . . . . . . . unbind component
##
DeclareOperationKernel( "Unbind.", [ IsObject, IsObject ], UNB_REC );
#############################################################################
##
#A RecNames( <rec> )
##
## returns a list of strings corresponding to the names of the record
## components of the record <rec>.
##
DeclareAttribute( "RecNames", IsRecord );
#############################################################################
##
#F RecFields( <record> )
##
BIND_GLOBAL( "RecFields", RecNames );
#############################################################################
##
#M RecNames( <record> ) . . . . . . . . . . . . . . . . names of components
##
InstallMethod( RecNames,
"for a record in internal representation",
[ IsRecord and IsInternalRep ],
REC_NAMES );
#############################################################################
##
#F NamesOfComponents( <obj> )
##
## For a component object <obj>, `NamesOfComponents' returns a list of
## strings, which are the names of components currently bound in <comobj>.
##
## For a record <obj>, `NamesOfComponents' returns the result of `RecNames'.
##
BIND_GLOBAL( "NamesOfComponents", function( obj )
if IsComponentObjectRep( obj ) then
return REC_NAMES_COMOBJ( obj );
elif IsRecord( obj ) then
return RecNames( obj );
else
Error( "<obj> must be a component object or a record" );
fi;
end );
#############################################################################
##
#m PrintObj( <record> )
##
## The record <record> is printed by printing all its components.
##
InstallMethod( PrintObj,
"record",
[ IsRecord ],
function( record ) PRINT_PREC_DEFAULT( record ); end );
#############################################################################
##
#m String( <record> ) . . . . . . . . . . . . . . . . . . . . for a record
##
InstallMethod( String,
"record",
[ IsRecord ],
function( record )
local str, nam, com;
str := "rec( ";
com := false;
for nam in RecNames( record ) do
if com then
Append( str, ", " );
else
com := true;
fi;
Append( str, nam );
Append( str, " := " );
if IsStringRep( record.( nam ) )
or ( IsString( record.( nam ) )
and not IsEmpty( record.( nam ) ) ) then
Append( str, "\"" );
Append( str, String( record.(nam) ) );
Append( str, "\"" );
else
Append( str, String( record.(nam) ) );
fi;
od;
Append( str, " )" );
ConvertToStringRep( str );
return str;
end );
#############################################################################
##
#m ViewObj( <record> ) . . . . . . . . . . . . . . . for a record (default)
##
##
InstallMethod( ViewObj,
"record",
[ IsRecord ],
function( record )
local nam, com, i;
Print("\>\>rec( \>\>");
com := false;
i := 1;
for nam in RecNames( record ) do
if com then
Print("\<,\< \>\>");
else
com := true;
fi;
SET_PRINT_OBJ_INDEX(i);
i := i+1;
Print(nam, " := ");
ViewObj(record.(nam));
od;
Print(" \<\<\<\<)");
end);
#############################################################################
##
#m <record> = <record>
##
InstallMethod( \=,
"record = record",
IsIdenticalObj,
[ IsRecord, IsRecord ],
EQ_PREC );
#############################################################################
##
#m <record> < <record>
##
InstallMethod( \<,
"record < record",
IsIdenticalObj,
[ IsRecord, IsRecord ],
LT_PREC );
# methods to catch error cases
#############################################################################
##
#m \.
##
InstallMethod(\.,"catch error",true,[IsObject,IsObject],0,
function(obj,nr)
local msg;
msg:=Concatenation("illegal access to record component `obj.",
NameRNam(nr),"'\n",
"of the object <obj>. (Objects by default do not have record components.\n",
"The error might be a relic from translated GAP3 code.) ");
Error(msg);
end);
#############################################################################
##
#m IsBound\.
##
InstallMethod(IsBound\.,"catch error",true,[IsObject,IsObject],0,
function(obj,nr)
local msg;
msg:=Concatenation("illegal access to record component `IsBound(obj.",
NameRNam(nr),")'\n",
"of the object <obj>. (Objects by default do not have record components.\n",
"The error might be a relic from translated GAP3 code.) ");
Error(msg);
end);
#############################################################################
##
#m Unbind\.
##
InstallMethod(Unbind\.,"catch error",true,[IsObject,IsObject],0,
function(obj,nr)
local msg;
msg:=Concatenation("illegal access to record component `Unbind(obj.",
NameRNam(nr),")'\n",
"of the object <obj>. (Objects by default do not have record components.\n",
"The error might be a relic from translated GAP3 code.) ");
Error(msg);
end);
#############################################################################
##
#m \.\:\=
##
InstallMethod(\.\:\=,"catch error",true,[IsObject,IsObject,IsObject],0,
function(obj,nr,elm)
local msg;
msg:=Concatenation("illegal assignement to record component `obj.",
NameRNam(nr),"'\n",
"of the object <obj>. (Objects by default cannot have record components.\n",
"The error might be a relic from translated GAP3 code.) ");
Error(msg);
end);
#############################################################################
##
#E
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