+* Errors in the input grammar are not fatal; Bison keeps reading
+the grammar file, and reports all the errors found in it.
+
+* Tokens can now be specified as multiple-character strings: for
+example, you could use "<=" for a token which looks like <=, instead
+of chosing a name like LESSEQ.
+
+* The %token_table declaration says to write a table of tokens (names
+and numbers) into the parser file. The yylex function can use this
+table to recognize multiple-character string tokens, or for other
+purposes.
+
+* The %no_lines declaration says not to generate any #line preprocessor
+directives in the parser file.
+
+* The %raw declaration says to use internal Bison token numbers, not
+Yacc-compatible token numbers, when token names are defined as macros.
+
+* The --no-parser option produces the parser tables without including
+the parser engine; a project can now use its own parser engine.
+The actions go into a separate file called NAME.act, in the form of
+a switch statement body.
+\f
+Changes in version 1.23:
+
+The user can define YYPARSE_PARAM as the name of an argument to be
+passed into yyparse. The argument should have type void *. It should
+actually point to an object. Grammar actions can access the variable
+by casting it to the proper pointer type.
+
+Line numbers in output file corrected.
+\f
+Changes in version 1.22:
+
+--help option added.