CookCC Yacc input allows CookCC to read traditional yacc/bison input files. However, there are some deviations since some features are not support by CookCC.


Non-terminal name restrictions

The pattern of non-terminal names recognized by CookCC is [_a-zA-Z][_a-zA-Z0-9]*.

Embedded actions are not supported

CookCC does not allow embedded action for yacc input at present. The presence of such grammar would result in parsing error.

An embedded action is like the following:

A   : B { /* embedded action */ } C
      { /* regular action */ }

It is equivalent to

A   : B T C
      { /* regular action */ }
T   :
      { /* embedded action */ }

Token declaration works somewhat differently

In CookCC, tokens declared using %token are treated as non-associative terminals (same as %nonassoc).

In contrast, in yacc / bison, tokens by default have the lowest precedence can be specified later again in %left, %right, %nonassoc directives to specify the precedence and associativity. CookCC does not allow tokens specified in %token directives to be specified in other token directives.

Code Sections

The code surrounded by %{ and %} pairs in section 1 of yacc input are treated as "fileheader" code.

The section 3 code of yacc input are treated as "default" code.