This glossary provides definitions of terms used in the ARexx manual.

• Address
  • An identifying number assigned to every byte of information in a computer's memory and every sector on a disk.

• argument
  • An additional piece of information included with an instruction or function. The argument determines the action to be taken.

• assignment clause
  • A variable symbol (simple, stem or compound symbol) followed by an = operator. In an assignment clause, the tokens to the right of the = sign are evaluated and the result is assigned to the variable symbol.

• Boolean
  • Having two possible states: 0 (false) or 1 (true).

• clause
  • The smallest executable language unit.

• clip list
  • A clipboard used for intertask communication. Name and value pairs can be added to the clip list with the SETCLIP() function.

• command clause
  • An ARexx expression in which the result is issued as a command to an external application.

• command interface
  • A message port through which ARexx issues commands to compatible applications.

• comment
  • A group of characters enclosed in /*...*/ symbols. Each ARexx program starts with a comment.

• compound symbol
  • A token made up of alphanumeric or ., !, ?, $, _ characters with one or more periods within the name. Compound symbols have the structure .

• concatenation
  • The process of linking together two strings.

• debugging
  • Finding and fixing errors in a program.

• delimiter
  • A character that marks the beginning and end of a string. ARexx delimiters are a single quote (') and a double quote (").

• expression
  • A group of tokens to be evaluated. Expressions are made up of strings, symbols, operators, and parentheses.

• fixed symbol
  • A token beginning with a digit or a period.

• function
  • A group of statements that can be executed as a whole. Functions allow you to build complex programs from smaller modules.

• function hosts
  • An external application that contains an ARexx port. The name of a function host is the name of the program's public message port.

• function libraries
  • A collection of one or more functions organized as an Amiga shared library. A function library must contain a library name, a search priority, an entry point offset, and a version number.

• global environment
  • The fixed components of an ARexx program, including the program source code, static data strings and argument strings.

• host address
  • In an outside application, the host address is the name of the message port to which ARexx commands can be sent.

• instruction
  • A clause beginning with a certain keyword that tells ARexx to perform an action.

• interprocess communication
  • The exchange of information between applications.

• interrupts
  • Internal flags in ARexx that allow a program to detect errors and retain control when the program would normally abort. Interrupts are controlled by the SIGNAL: instruction.

• iterating
  • Repeating a section of a program.

• label
  • A symbol token followed by a colon (:). Labels identify a particular location in the program.

• library list
  • An internal list, maintained by ARexx, of all the currently available function libraries and function hosts. Applications can add or remove functions as needed.

• macro
  • Another name for an ARexx program.

• marker
  • A token that determines the beginning and end of a parse string.

• message port
  • An interface in an Amiga application that allows the program to communicate with an ARexx program.

• null clause
  • A blank line or a comment line.

• numeric precision
  • The number of decimal places in an arithmetic result. As the number of decimal places decreases, the result becomes less precise.

• operators
  • A character such as (+), (-), or (|) used in an arithmetic, concatenation, comparison, or logical operation.

• parsing
  • Breaking a string into smaller units.

• return code
  • The severity level of an error. This number (5, 10, or 20) is displayed when an error occurs in an ARexx program.

• RexxMast
  • The program that acts as an interpreter for ARexx programs.

• simple symbol
  • A token that does not begin with a digit or contain any periods.

• statement
  • An assignment, instruction, or command clause.

• stem symbol
  • A token that has one period at the end of its name. Stem symbols are used to initialize compound symbols.

• storage environment
  • The variable components of an ARexx program, including the symbol table, numeric options, trace options and host address strings.

• string
  • A group of characters beginning and ending with a delimiter (single or double quote). The value of a string is the string itself.

• symbol
  • Any group of the alphanumeric characters a-z, A-Z, 0-9, period (.), exclamation point (!), question mark (?), dollar sign ($), or underscore (_).

• symbol table
  • An internal table created by ARexx that stores the value strings that have been assigned to the variables in a program.

• target
  • A symbol, usually a variable symbol, that is assigned a value during a parsing operation.

• template
  • A group of tokens that specifies the variables used in a parsing operation. It also specifies the way in which the values will be determined.

• tokenization
  • The process of breaking a statement into its individual tokens.

• tokens
  • The smallest entities of the ARexx language.

• tracing
  • Displaying the lines of an ARexx program as the program is executing. This allows you to determine exactly where any errors are occurring.

• variable
  • A symbol that can be assigned a value.