Glossary: Glossary

Glossary

argument list: the values that are passed to a routine for processing. These values can be any SCL expressions, such as variable names, numeric or character literals, or computed values.
assignment statement: a DATA step statement that evaluates an expression and stores the result in a variable. An assignment statement has the following form: variable=expression ;
attention handler: a block of code that is executed when a user interrupts the application with the system's BREAK, INTERRUPT, or ATTENTION key. A CONTROL BREAK statement installs an attention handler by specifying a user-defined statement label. The block of code that follows the statement label is executed when a user interrupts the program.
attribute: a property of a SAS/AF component such as its color, size, or description. Unlike instance variables, which store only the name, value, and type of a component, attributes can specify many types of additional information (metadata) about components.
autoexec file: a file that contains SAS statements that are executed automatically when SAS is invoked. The autoexec file can be used to specify some of the SAS system options, as well as to assign librefs and filerefs to data sources that are used frequently. See also libref, fileref.
automatic instance variable: an instance variable whose value is automatically copied into the corresponding SCL variable when an SCL method executes. The value of the variable is also copied back into the object when the method returns. Assigning the automatic status to an instance variable makes writing new methods for a class much easier because the SCL method can access the automatic instance variable directly instead of accessing it indirectly with SCL list functions. See also instance variable.
block menu: a menu in which choices are represented as blocks, as icons, or as text on the display device. The choices that are represented by blocks are generated by the BLOCK statement in SCL or by block objects in FRAME entries.
branching: the process of continuing program execution with an executable statement that does not immediately follow the statement that is currently executing.
breaking: in the SCL debugger, the process of suspending program execution.
breakpoint: the location in an SCL program at which the SCL debugger suspends program execution.
call-by-reference: a type of parameter passing in which the parameters are variable names or array references. Call-by-reference parameter passing allows values to be returned to the calling program. See also call-by-value, parameter passing.
call-by-value: a type of parameter passing in which the parameters are numeric constants, character constants, or expressions. Call-by-value parameter passing does not allow values to be returned to the calling program. See also call-by-reference, parameter passing.
class: in object-oriented programming, the template or model for an object. A class includes data that describes the object's characteristics (attributes or instance variables) and the operations (methods) that the object can perform. See also subclassing, object.
command list: a sublist (named _CMDLIST_) of the local environment list. The command list contains the components of the DM command that was used to invoke the current SAS/AF application. See also environment list, local environment list.
control level: one of the determinants in the kind of lock that a task obtains on a SAS data set or on an observation in the data set. The control level specifies how other SAS tasks can access the SAS data set concurrently. Every SAS task has an open mode and a default control level for each SAS data set that it accesses, based on how the task operates on that data set. See also locking, open mode.
data set: See SAS data set.
data set data vector (DDV): a temporary storage area for the values of the variables from one observation of a data set that was opened by the current program. The DDV is empty until an observation is read from the associated data set.
data set identifier (DSID): a unique, positive number that is returned by the OPEN function to identify a newly opened data set each time the program runs. This number is cleared either by the CLOSE function or when the program terminates.
DATA step: a group of statements in a SAS program that begins with a DATA statement and ends with either a RUN statement, another DATA statement, a PROC statement, or the end of the job. The DATA step enables you to read raw data or other SAS data sets and to create SAS data sets.
declarative statement: a statement that provides information to the SCL compiler but which does not result in executable code unless initial values are assigned to the declared variables. For example, the DECLARE, LENGTH, and ARRAY statements are declarative statements. See also executable statement.
DO group: a sequence of statements that starts with a simple DO statement and that ends with a corresponding END statement. See also DO loop.
DO loop: a sequence of statements headed by an iterative DO, DO WHILE, or DO UNTIL statement; ended by a corresponding END statement; and executed (usually repeatedly) according to directions in the DO statement. See also DO group.
entry: See SAS catalog entry.
environment list: a special SCL list that contains local or global values. Values that are placed in local environment lists are available only in the same SCL application invocation. Values that are placed in global environment lists can be accessed in any SCL application. The lists can contain numeric, character, and sublist items, all of which can be retrieved by specifying their names. Names in environment lists do not have to be valid SAS names. See also global environment list, local environment list.
executable statement: any SCL statement that is compiled into intermediate code and that results in some action when the SCL program is executed. For example, the CURSOR, IF-THEN/ELSE, and assignment statements are executable statements. See also declarative statement.
execution phase: the stage at which an SCL program is executed, from initialization through termination. During this phase, the program typically validates field values, calculates values for computed variables based on user input, invokes secondary windows, issues queries, executes user-issued commands, and retrieves values from SAS data sets or from external files.
execution stack: a last-in, first-out stack that lists the current and inactive entries that were called during the execution of a SAS/AF, FSEDIT, or FSVIEW application.
expression: See SCL expression.
extended table: a window (in a PROGRAM entry) or a window element (in a FRAME entry) that displays values in a tabular format by repeating a set of fields (or other objects, in a FRAME entry). The number of rows that are displayed is determined by the SAS Component Language program or by an attribute of the extended table object in the FRAME entry. Extended tables are either static or dynamic. For static extended tables, the number of rows is fixed. For dynamic extended tables, the number of rows can vary.
external file: a file that is created and maintained by a host operating system or by another vendor's software application. SAS can read data from and route output to external files. External files can contain raw data, SAS programming statements, procedure output, or output that was created by the PUT statement. A SAS data set is not an external file. See also fileref.
FDB (file data buffer): a temporary storage area for one record value of an external file that has been opened by a program. The FDB is empty until a record is read from the associated file. Record values remain in the FDB until another record is read in, until the record is written back to the file, or until the file is closed.
field: a window area in which users can view, enter, or modify a value.
field validation: the process of checking user-entered values either against attributes that have been specified for a field or against conditions that have been specified in a SAS Component Language program.
file data buffer (FDB): See FDB (file data buffer).
fileref (file reference): a name that is temporarily assigned to an external file or to an aggregate storage location such as a directory or folder. The fileref identifies the file or the storage location to SAS. See also libref.
flow of control: the order in which SCL statements are executed. The flow of control can be altered by conditional statements such as IF/THEN-ELSE, LINK, and RETURN.
function: a component of the SAS programming language that can accept arguments, perform a computation or other operation, and return a value. For example, the ABS function returns the absolute value of a numeric argument. Functions can return either numeric or character results. Some functions are included with SAS. Users can also use SAS/TOOLKIT software to write their own functions.
global environment list: an environment list containing data that all SCL applications can share during a SAS session. The data remains in the global environment list until SCL execution explicitly removes the data or until the SAS session ends. See also environment list, local environment list.
index: in SAS software, a component of a SAS data set that enables SAS to access observations in the SAS data set quickly and efficiently. The purpose of SAS indexes is to optimize WHERE-clause processing and to facilitate BY-group processing.
initialization phase: in SAS Component Language, the stage at which initialization steps are performed before a window is displayed in SAS/AF software or before an observation is displayed in SAS/FSP software.
inner sublist: in a nested SCL list, the innermost list. See also nested list, outer list.
instance variable: a characteristic or data value that is associated with an object, such as its description, its color or label, or other data that the object must store so that it can perform its operations. All objects that are created from the same class automatically contain the instance variables that have been defined for that class, but the values of those variables can change from one object to another. In addition, objects can contain local instance variables?that is, variables that are local to a particular instance of a class. Beginning in Version 8, the use of attributes reduced the need for instance variables. See also automatic instance variable, attribute.
jumping: in the SCL debugger, the process of altering the flow of control by restarting program execution at a specified line, bypassing any intervening statements.
key variable: a variable that is used to index SAS data sets.
legend window: a display-only, dynamic window for presenting information to users. By default, the legend window has four lines of text and is positioned at the top of the display.
libref (library reference): a name that is temporarily associated with a SAS data library. The complete name of a SAS file consists of two words, separated by a period. The libref, which is the first word, indicates the library. The second word is the name of the specific SAS file. For example, in VLIB.NEWBDAY, the libref VLIB tells SAS which library contains the file NEWBDAY. You assign a libref with a LIBNAME statement or with an operating system command.
list box: a rectangular window element that contains a scrollable list of items.
list identifier: a unique number that is assigned to each SCL list that is created in an application.
loaded program: a program that resides in the execution stack. See also execution stack.
local environment list: an environment list that contains data that is available only to SCL entries that are invoked in the same SCL application. This list is deleted when the application ends. See also environment list, global environment list.
local host: the computer on which you use a SAS session to initiate a link with (log on to) a remote host. See also remote host.
locking: a technique for preventing conflicts among requests from different SAS tasks. A task obtains a lock on a member (for example, a SAS data set) or a record (observation) based on the open mode and control level for that SAS data set. See also control level, open mode.
logical row: a row of fields or objects that is repeated in an extended table. See also extended table.
message area: the area immediately beneath a window's command line or menu bar which displays messages from SAS or from the SAS Component Language reserved variable _MSG_.
method: in object-oriented methodology, an operation that is defined for a class and which can be executed by an object that is created from that class. Methods can be defined in SCL and can be implemented with SCL routines.
method block: in SCL entries, a labeled group of statements that begins with a METHOD statement, ends with an ENDMETHOD statement, and contains one or more SCL statements. A method block can be called by different SAS/AF entries.
named list: a list structure that contains one or more items to which names have been assigned.
nested list: a data structure in which a list contains sublists. These sublists, called nested lists, are especially useful for creating collections of records or other data structures.
nonwindow variable: a variable that is used in a program but which is not associated with an object in a window. Values for nonwindow variables are stored in the SCL data vector (SDV) until the SCL program terminates and closes the SDV. See also SCL data vector (SDV).
object: in object-oriented methodology, a specific representation of a class. An object inherits the characteristics (attributes or instance variables) of its class as well as the operations (methods) that class can execute. For example, a push button object is an instance of the Push Button class. The terms object and instance are often used interchangeably.
open mode: the way in which a SAS task accesses and operates on a member in a SAS data library. There are three open modes for SAS files: input, update, and output. See also control level, locking.
outer list: the first list in a nested-list structure. An outer list contains one or more sublists. See also nested list.
parameter: (1) in SAS/AF and SAS/FSP applications, a window characteristic that can be controlled by the user. (2) in SAS Component Language (SCL), a value that is passed from one entry in an application to another. For example, in SAS/AF applications, parameters are passed between entries by using the CALL DISPLAY and ENTRY statements. (3) a unit of command syntax other than the keyword. For example, NAME=, TYPE=, and COLOR= are typical command parameters that can be either optional or required.
parameter list: the values that a program receives from a calling program through the ENTRY statement. These values can be any SCL expression, such as variables, numeric or character literals, or computed values. See also parameter passing.
parameter passing: the process of communicating values from a calling program to a receiving program. You use the ENTRY statement in receiving programs to declare parameters. See also call-by-reference, call-by-value.
program data vector: the temporary area of computer memory in which SAS builds a SAS data set, one observation at a time. The program data vector is a logical concept and does not necessarily correspond to a single contiguous area of memory.
program variable: a variable that is used in an SCL program. See also nonwindow variable, window variable.
record: a logical unit of information that consists of fields of related data. A collection of records are stored in a file. A record is analogous to a SAS observation.
recursive list: a data structure in which a list can contain itself or other sublists that contain it either directly or indirectly.
remote host: a computer that is in a different location than your computer but which you can log on to from your computer. See also local host.
remote session: a SAS session that is running in a special mode on the remote host. No output or log messages are displayed on the remote host. Instead, the results of a remote SAS session are transmitted back to the log file and output files on the local host.
reserved label: a special label that indicates when the corresponding section of an SCL program executes. Examples include INIT, MAIN, TERM, FSEINIT, FSETERM, GETROW, and PUTROW.
return code: a value returned by an SCL function that indicates whether the function successfully accomplished the specified task.
RGB: a color-coding scheme that specifies a color in terms of percentages of red, green, and blue components.
SAS catalog entry: a separate storage unit within a SAS catalog. Each entry has an entry type that identifies its purpose to SAS. Some catalog entries contain system information such as key definitions. Other catalog entries contain application information such as window definitions, Help windows, formats, informats, macros, or graphics output.
SAS data library: a collection of one or more SAS files that are recognized by SAS and which are referenced and stored as a unit. Each file is a member of the library.
SAS data set: a file whose contents are in one of the native SAS file formats. There are two types of SAS data sets: SAS data files and SAS data views. SAS data files contain data values in addition to descriptor information that is associated with the data. SAS data views contain only the descriptor information plus other information that is required for retrieving data values from other SAS data sets or from files whose contents are in other software vendors' file formats.
SAS/ACCESS software: a group of software interfaces, each of which makes data from a particular external database management system (DBMS) directly available to SAS, as well as making SAS data directly available to the DBMS.
SASUSER library: a default, permanent SAS data library that is created at the beginning of your first SAS session. The SASUSER library contains a PROFILE catalog that stores the customized features or settings that you specify for SAS. You can also store other SAS files in this library.
SCL data vector (SDV): a temporary storage area for the values of all SCL variables for the current program. The SDV is deleted when the program terminates.
SCL expression: a sequence of operands and operators that form a set of instructions that are performed to produce a result value. Operands can be variable names or constants, and they can be numeric, character, or both. Operators can be symbols that request a comparison, a logical operation, or an arithmetic calculation. Operators can also be SAS functions and grouping parentheses. Alternatively, an SCL expression can be a single variable name, constant, or function.
SCL statement: a string of keywords, names, special characters, and operators that instructs the SCL compiler to perform an operation, gives information to the compiler, or controls the behavior of certain aspects of an application's window. There are two types of SCL statements: declarative statements, which provide information to the SCL compiler but do not result in executable code, and executable statements, which are compiled into intermediate code and result in some action when the SCL program is executed. Every SCL statement must end with a semicolon.
SCL variable: a named storage location to which values can be written and from which values can be retrieved. A value is referenced through the use of the variable's name in the SCL program. Some SCL variables are automatically linked to fields and objects in an application's window. See also window variable, nonwindow variable.
SDV (SCL data vector): See SCL data vector (SDV).
selection list: a list of items in a window, from which users can make one or more selections. Sources for selection lists are LIST entries, special SCL functions, and extended tables.
shared data environment: a feature of SCL that enables you to share data among multiple program entries within a single SCL application by placing that data in a local environment list, and to share data among multiple SCL applications that have been started in the same SAS session or process by storing that data in a global environment list. See environment list, global environment list, local environment list.
stepping over: a SAS Component Language debugging process that treats a DISPLAY, FSEDIT, or FSVIEW routine as a single statement that the debugger does not step through. Debugging continues at the next executable statement of the current SCL program. See also stepping through.
stepping through: a SAS Component Language debugging process that enables a program that is called by a DISPLAY, FSEDIT, or FSVIEW routine to be debugged as a series of single statements, suspending execution at each statement. This process is also known as stepping into.
subclassing: in object-oriented methodology, the process of deriving a new class from an existing class. A new class inherits the characteristics (attributes or instance variables) and operations (methods) of its parent. It can also possess custom attributes (or instance variables) and methods. See also class, attribute, instance variable, method.
SUBMIT block: a group of SAS statements that are submitted together to SAS for processing. A SUBMIT block consists of a SUBMIT statement, one or more SAS language statements, and an ENDSUBMIT statement.
system variable: a reserved variable that is automatically defined. For example, _MSG_ and _STATUS_ are system variables.
table lookup: a processing technique in which information is retrieved from an auxiliary source, based on the values of variables in the primary source.
termination phase: in SAS Component Language, the stage at which a program processes any steps that are required before the current observation is written to the data set and another observation is read.
tracepoint: the location in an SCL program at which the SCL debugger temporarily suspends execution, displays a notification message, and resumes program execution.
variable: in data vectors, a location in the SCL data vector or the program data vector to which values can be written and from which values can be read. Variables can be permanent or temporary. See also SCL data vector (SDV), program data vector.
watched variable: a variable that the SCL debugger monitors during program execution. If the value of a watched variable changes, the debugger suspends execution and displays the old and new values of the variable. A watched variable is monitored continuously until the watch is canceled.
WHERE clause: one or more WHERE expressions used in a WHERE statement, a WHERE function, or a WHERE= data set option.
WHERE expression: a type of SAS expression that specifies a criterion or search condition. Observations that meet that criterion are selected for processing.
widget: a component of a graphical user interface that displays information or accepts user input. For example, a text entry field is a widget that is used for displaying and entering text.
window variable: a variable that passes values back and forth between an SCL program and an application window. Each window variable is linked to a particular field in a window.
WORK data library: a SAS data library that is automatically defined by SAS at the beginning of each SAS session or SAS job. The WORK library contains SAS files that are temporary by default. When the libref USER is not defined, SAS uses WORK as the default library for SAS files that are created with one-level names.

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