Lex Specifications[slide by John Werth.]

   %{  declarations  %}
   regular definitions
   %%
   translation rules
   %%
   auxiliary procedures

• declarations: include and manifest constants (identifier declared to represent a constant).

• regular definitions: definition of named syntactic constructs such as letter using regular expressions.

• translation rules: pattern / action pairs

• auxiliary procedures: arbitrary C functions copied directly into the generated lexical analyzer.