Ayacc is an Ada parser generator in the style of yacc(1).

The first implementation was written by David Taback and Deepak Tolani at the University of California, Irvine. The last version that was released appeared to be the Ayacc 1.1 released in 1994.

Ayacc was used and improved by P2Ada, the Pascal to Ada translator. This version of Ayacc is derived from the P2Ada ayacc implementation released in August 2010.

This version brings a number of improvements:

• Ayacc now uses more standard options to configure the code generation
• The parser was improved to configure the parser stack size and support Ada child packages.
• The grammar supports the %unit directive to control the Ada child packages.
• Several options provide a better control of the generated code.
• Ayacc can generate a reentrant parser.