<!doctype html> <html> <head> <title>CodeMirror: EBNF Mode</title> <meta charset="utf-8"/> <link rel=stylesheet href="../../doc/docs.css"> <link rel="stylesheet" href="../../lib/codemirror.css"> <script src="../../lib/codemirror.js"></script> <script src="../javascript/javascript.js"></script> <script src="ebnf.js"></script> <style type="text/css">.CodeMirror {border-top: 1px solid black; border-bottom: 1px solid black;}</style> </head> <body> <div id=nav> <a href="http://codemirror.net"><h1>CodeMirror</h1><img id=logo src="../../doc/logo.png"></a> <ul> <li><a href="../../index.html">Home</a> <li><a href="../../doc/manual.html">Manual</a> <li><a href="https://github.com/codemirror/codemirror">Code</a> </ul> <ul> <li><a href="../index.html">Language modes</a> <li><a class=active href="#">EBNF Mode</a> </ul> </div> <article> <h2>EBNF Mode (bracesMode setting = "javascript")</h2> <form><textarea id="code" name="code"> /* description: Parses end executes mathematical expressions. */ /* lexical grammar */ %lex %% \s+ /* skip whitespace */ [0-9]+("."[0-9]+)?\b return 'NUMBER'; "*" return '*'; "/" return '/'; "-" return '-'; "+" return '+'; "^" return '^'; "(" return '('; ")" return ')'; "PI" return 'PI'; "E" return 'E'; <<EOF>> return 'EOF'; /lex /* operator associations and precedence */ %left '+' '-' %left '*' '/' %left '^' %left UMINUS %start expressions %% /* language grammar */ expressions : e EOF {print($1); return $1;} ; e : e '+' e {$$ = $1+$3;} | e '-' e {$$ = $1-$3;} | e '*' e {$$ = $1*$3;} | e '/' e {$$ = $1/$3;} | e '^' e {$$ = Math.pow($1, $3);} | '-' e %prec UMINUS {$$ = -$2;} | '(' e ')' {$$ = $2;} | NUMBER {$$ = Number(yytext);} | E {$$ = Math.E;} | PI {$$ = Math.PI;} ;</textarea></form> <script> var editor = CodeMirror.fromTextArea(document.getElementById("code"), { mode: {name: "ebnf"}, lineNumbers: true, bracesMode: 'javascript' }); </script> <h3>The EBNF Mode</h3> <p> Created by <a href="https://github.com/robertleeplummerjr">Robert Plummer</a></p> </article> </body> </html>