What is a macro?

Question

In computer terms.

Answer 1

macro

[techspeak] A name (possibly followed by a formal arg list) that is equated to a text or symbolic expression to which it is to be expanded (possibly with the substitution of actual arguments) by a macro expander. This definition can be found in any technical dictionary; what those won't tell you is how the hackish connotations of the term have changed over time.

The term macro originated in early assemblers, which encouraged the use of macros as a structuring and information-hiding device. During the early 1970s, macro assemblers became ubiquitous, and sometimes quite as powerful and expensive as HLLs, only to fall from favor as improving compiler technology marginalized assembler programming (see languages of choice). Nowadays the term is most often used in connection with the C preprocessor, LISP, or one of several special-purpose languages built around a macro-expansion facility (such as TeX or Unix's [nt]roff suite).

Indeed, the meaning has drifted enough that the collective macros is now sometimes used for code in any special-purpose application control language (whether or not the language is actually translated by text expansion), and for macro-like entities such as the keyboard macros supported in some text editors (and PC TSR or Macintosh INIT/CDEV keyboard enhancers).

Answer 2

Beyond the wikepedia definitions...

I always thought of a macro as a script that manipulates the software package that can understand the macro's instructions.

In Microsoft Office Suite Pro, the macros are defined in script called VBA. Script can be authored with sophisticated logic and do such things like open template documents, fill the document with text and save. The script can then be attached to a button. At that point it becomes a macro.

I've seen the same thing for Keyboard shortcuts in MacOS. Some software packages, such as Photoshop and the before mentioned MS Office, will "record" a macro and no script is necessary from the user. You hit the Record button, make the mouse and keyboard actions, hit stop record and assign the recording(macro). If we know the script we can fine tune it at that point by editing.

In short a macro is an abbreviation that expands into an action following a script.

Answer 3

A macro in computer science is an abstraction, that defines how a certain input pattern is replaced by an output pattern according to a defined set of rules. There are three broad categories of macros, and each takes a different kind of input pattern to produce a different kind of output pattern.

Programming macros take a computer program as input and output a new, expanded program. Hence, this process is called macro-expansion and the tool that does this is called a macro-expander or a preprocessor. For many programming languages, a macro expander is included in the interpreter or compiler. These macros are typically used to enable a higher level of abstraction in programming languages.

Keyboard macros and application macros take a simple command as input and then output a new expanded set of commands or instructions. These macros are typically used to automate frequently-used sequences or lists of keystrokes or mouse movements.

Answer 4

A macro in computer science is an abstraction, that defines how a certain input pattern is replaced by an output pattern according to a defined set of rules. There are three broad categories of macros, and each takes a different kind of input pattern to produce a different kind of output pattern.

Programming macros take a computer program as input and output a new, expanded program. Hence, this process is called macro-expansion and the tool that does this is called a macro-expander or a preprocessor. For many programming languages, a macro expander is included in the interpreter or compiler. These macros are typically used to enable a higher level of abstraction in programming languages.

Keyboard macros and application macros take a simple command as input and then output a new expanded set of commands or instructions. These macros are typically used to automate frequently-used sequences or lists of keystrokes or mouse movements.