Oh, in case anyone wants to follow the development of X3, here are the Github links:<\/p>\n
https:\/\/github.com\/djowel\/spirit_x3<\/a>
\nhttps:\/\/github.com\/djowel\/spirit_x3.git<\/a>
\ngit@github.com:djowel\/spirit_x3.git<\/a><\/p><\/blockquote>\nThe full attribute mechanism works + basic C++lambda support. I’ve ported one example (calc4.cpp) which parses to an AST. The AST remains the same. Only the way the grammars are written had to change.<\/p>\n
For a teaser: here’s GCC times:<\/p>\n
SpiritX3: TOTAL :\u00a0\u00a0 4.27 secs
\nSpirit2:\u00a0 TOTAL :\u00a0 10.00 secs<\/p>\nEven faster at CT than the first Spirit3 attempt. Runtime speed? I expect it to be faster than Spirit-2. The rules have changed (pun intentional). Now, there’s no longer the need for virtual functions and auto is used extensively. I expect code size to be smaller too because the compiler can generate more efficient code.<\/p>\n
Here’s the calculator grammar (based on calc3.cpp):<\/p>\n
\r\n\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\r\n\/\/ The calculator grammar\r\n\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\r\nnamespace calculator_grammar\r\n{\r\n using x3::uint_;\r\n using x3::char_;\r\n\r\n x3::rule<class expression, ast::program> const expression;\r\n x3::rule<class term, ast::program> const term;\r\n x3::rule<class factor, ast::operand> const factor;\r\n\r\n auto const expression_def =\r\n term\r\n >> *( (char_('+') >> term)\r\n | (char_('-') >> term)\r\n )\r\n ;\r\n\r\n auto const term_def =\r\n factor\r\n >> *( (char_('*') >> factor)\r\n | (char_('\/') >> factor)\r\n )\r\n ;\r\n\r\n auto const factor_def =\r\n uint_\r\n | '(' >> expression >> ')'\r\n | (char_('-') >> factor)\r\n | (char_('+') >> factor)\r\n ;\r\n\r\n auto const calculator = x3::grammar(\r\n expression = expression_def,\r\n term = term_def,\r\n factor = factor_def\r\n );\r\n}\r\n\r\nusing calculator_grammar::calculator;\r\n<\/pre>\nShare this:<\/h3>