bistromathic - all the bells and whistles

This example demonstrates best practices when using Bison.

• Its hand-written scanner tracks locations.
• Its interface is pure.
• It uses %params to pass user information to the parser and scanner.
• Its scanner uses the error token to signal lexical errors and enter error recovery.
• Its interface is “incremental”, well suited for interaction: it uses the push-parser API to feed the parser with the incoming tokens.
• It features an interactive command line with completion based on the parser state, based on yyexpected_tokens.
• It uses Bison's standard catalog for internationalization of generated messages.
• It uses a custom syntax error with location, lookahead correction and token internationalization.
• Error messages quote the source with squiggles that underline the error:

> 123 456
1.5-7: syntax error: expected end of file or + or - or * or / or ^ before number
    1 | 123 456
      |     ^~~

• It supports debug traces with semantic values.
• It uses named references instead of the traditional $1, $2, etc.

To customize the interaction with bistromathic, see the GNU Readline user manual (see info rluserman).