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diff --git a/doc/gawk.texi b/doc/gawk.texi index ad2cc6fe..40c85a81 100644 --- a/doc/gawk.texi +++ b/doc/gawk.texi @@ -868,6 +868,7 @@ particular records in a file and perform operations upon them. * TCP/IP Networking:: Using @command{gawk} for network programming. * Profiling:: Profiling your @command{awk} programs. +* Extension Philosophy:: What should be built-in and what should not. * Advanced Features Summary:: Summary of advanced features. * I18N and L10N:: Internationalization and Localization. * Explaining gettext:: How GNU @command{gettext} works. @@ -29251,6 +29252,7 @@ discusses the ability to dynamically add new built-in functions to * Two-way I/O:: Two-way communications with another process. * TCP/IP Networking:: Using @command{gawk} for network programming. * Profiling:: Profiling your @command{awk} programs. +* Extension Philosophy:: What should be built-in and what should not. * Advanced Features Summary:: Summary of advanced features. @end menu @@ -30525,6 +30527,52 @@ Profiling and pretty-printing also preserve the original format of numeric constants; if you used an octal or hexadecimal value in your source code, it will appear that way in the output. +@node Extension Philosophy +@section Builtin Features vs.@: Extensions + +As this and subsequent @value{CHAPTER}s show, @command{gawk} has a +large number of extensions over standard @command{awk} built-in to +the program. These have developed over time. More recently, the +focus has moved to using the extension mechanism (@pxref{Dynamic Extensions}) +for adding features. This @value{SECTION} discusses the ``guiding philosophy'' +behind what should be added to the interpreter as a built-in +feature vs.@: what should be done in extensions. + +There are several goals: + +@enumerate 1 +@item +Keep the language @command{awk}; it should not become unrecognizable, even +if programs in it will only run on @command{gawk}. + +@item +Keep the core from getting any larger unless absolutely necessary. + +@item +Add new functionality either in @command{awk} scripts (@option{-f}, +@code{@@include}) or in loadable extensions written in C or C++ +(@option{-l}, @code{@@load}). + +@item +Extend the core interpreter only if some feature is: + +@c sublist +@enumerate A +@item +Truly desirable. +@item +Cannot be done via (2) or (3) above. +@item +Can be implemented without too much pain in the core. +@end enumerate +@end enumerate + +Combining modules with @command{awk} files is a powerful technique. +Some of the sample extensions demonstrate this. + +Loading extensions and library files should not be done automatically, +because then there's overhead that most users don't want or need. + @node Advanced Features Summary @section Summary @@ -30567,6 +30615,9 @@ you tune them more easily. Sending the @code{USR1} signal while profiling cause @item You can also just ``pretty-print'' the program. +@item +New features should be developed using the extension mechansim if possible, and added +to the core interpreter only as a last resort. @end itemize |