M4

M4 is a macro processing language.

A list of M4 resources may be found at http://www.m4site.com

A macro-processor is a text-replacement tool. It's chief use is to re-use text templates, typically in programming applications, but also in text editing, text processing applications.

Macro-processors were prevalent when assembly language programming was the common tool of programmers. In these early days of programming, the programmers noted that much of their program was repeated text. Simple means to re-use this text were invented. Programmers soon discovered it easy to not only resuse entire blocks of text, but, on occasion, substitute different values for similar paramters. This defined the usage range of macro processors. M4 offers these facilities:

• text replacement
• parameter substitution
• file inclusion
• string manipulation
• condtional evaluation
• arithmetic expressions
• system interface
• programmer diagnostics

Different from earlier macro-processors, it is not targeted at any other computer or human language.

---

There is a gnu version of m4.

Link: (http://www.gnu.org)

---

• The M4 is a major British motorway which runs from Chiswick, west of London, into Wales.
• The M4 is also a motorway in Sydney, Australia, running from the western suburb of Emu Plains to the inner western suburb of Strathfield.