Next: , Previous: Old Extension Problems, Up: Extension Design


C.5.2 Goals For A New Mechanism

Some goals for the new API were:

Some additional important goals were:

During development, it became clear that there were other features that should be available to extensions, which were also subsequently provided:

The requirement to avoid access to gawk's symbols is, at first glance, a difficult one to meet.

One design, apparently used by Perl and Ruby and maybe others, would be to make the mainline gawk code into a library, with the gawk utility a small C main() function linked against the library.

This seemed like the tail wagging the dog, complicating build and installation and making a simple copy of the gawk executable from one system to another (or one place to another on the same system!) into a chancy operation.

Pat Rankin suggested the solution that was adopted. See Extension Mechanism Outline, for the details.


Footnotes

[1] The symbols are the variables and functions defined inside gawk. Access to these symbols by code external to gawk loaded dynamically at runtime is problematic on Windows.