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