Replaced and Removed Command Names
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Group Actions – Name Changes
group operations

The concept of a group action is sometimes referred to as a group operation. In &GAP; 3 as well as in older versions of &GAP; 4 the term Operation was used instead of Action. We decided to change the names to avoid confusion with the term operation as in and operations for Xyz.

Here are some examples of such name changes.

Operation
RepresentativeOperation
OperationHomomorphism
FunctionOperation

OLD
NOW USE
Operation
RepresentativeOperation
OperationHomomorphism
FunctionOperation

Package Interface – Obsolete Functions and Name Changes

With &GAP; 4.4 the package interface was changed. Thereby some functions became obsolete and the names of some others were made more consistent.

DeclarePackage
DeclareAutoPackage
DeclarePackageDocumentation
DeclarePackageAutoDocumentation
The following functions are no longer needed: DeclarePackage, DeclareAutoPackage, DeclarePackageDocumentation and DeclarePackageAutoDocumentation. They are substituted by entries in the packages' PackageInfo.g files, see .

Furthermore, the global variable PACKAGES_VERSIONS is no longer needed, since this information is now contained in the GAPInfo.PackagesInfo record (see ). The global variable Revisions is also no longer needed, since the function DisplayRevision was made obsolete in &GAP; 4.5.

The following function names were changed.

RequirePackage
ReadPkg
RereadPkg

OLD
NOW USE
RequirePackage
ReadPkg
RereadPkg

Normal Forms of Integer Matrices – Name Changes
Smith normal form
Hermite normal form

Former versions of &GAP; 4 documented several functions for computing the Smith or Hermite normal form of integer matrices. Some of them were never implemented and it was unclear which commands to use. The functionality of all of these commands is now available with and a few interface functions.

Miscellaneous Name Changes or Removed Names
QUIET
BANNER

In former releases of &GAP; 4 there were some global variable names bound to general information about the running &GAP;, such as path names or command line options. Although they were not officially documented they were used by several users and in some packages. We mention here BANNER and QUIET. This type of information is now collected in the global record .

Here are some further name changes.

MonomialTotalDegreeLess
NormedVectors
MutableIdentityMat
MutableNullMat

OLD
NOW USE
MonomialTotalDegreeLess
NormedVectors
MutableIdentityMat
MutableNullMat

is an info class to display warnings when an obsolete variable is used. By default, these warnings are switched off since the info level for this class is 0. Setting it to 1 will trigger warnings if &GAP; will detect that an obsolete variable is used at runtime (this detection is possible, however, only for obsolete variables declared using DeclareObsoleteSynonym).

To check that the &GAP; code does not use obsolete variables at the parsing time, and not at a runtime, use -O command line option, see .
The former .gaprc file

Up to &GAP; 4.4, a file .gaprc in the user's home directory (if available, and &GAP; was started without -r option) was read automatically during startup, early enough for influencing the autoloading of packages and late enough for being allowed to execute any &GAP; code. On Windows machines this file was called gap.rc.

In &GAP; 4.5 the startup mechanism has changed, see for details. These new configuration files are now contained in a directory GAPInfo.UserGapRoot.

For the sake of partial backwards compatibility, also the former file ~/.gaprc is still supported for such initializations, but this file is read only if the directory GAPInfo.UserGapRoot does not exist. In that case the ~/.gaprc is read at the same time as gaprc would be read, i. e., too late for influencing the startup of &GAP;.

As before, the command line option -r disables reading ~/.gaprc, see .

To migrate from the old setup to the new one introduced with &GAP; 4.5, first have a look at the function . Many users will find that all or most of what was set in the old ~/.gaprc file can now be done via the user preferences in a gap.ini file. If you had code for new functions or abbreviations in your old ~/.gaprc file or you were reading additional files, then move this into the file gaprc (without the leading dot, same name for all operating systems) in the directory GAPInfo.UserGapRoot.